Academic literature on the topic 'Seedling traits'
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Journal articles on the topic "Seedling traits"
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Harrison, Susan, and Marina LaForgia. "Seedling traits predict drought-induced mortality linked to diversity loss." Proceedings of the National Academy of Sciences 116, no. 12 (2019): 5576–81. http://dx.doi.org/10.1073/pnas.1818543116.
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Trait-based approaches are increasingly used to predict ecological consequences of climate change, yet seldom have solid links been established between plant traits and observed climate-driven community changes. Most analyses have focused on aboveground adult plant traits, but in warming and drying climates, root traits may be critical, and seedlings may be the vulnerable stage. Relationships of seedling and root traits to more commonly measured traits and ecological outcomes are poorly known. In an annual grassland where winter drought-induced seedling mortality is driving a long-term decline in native diversity, using a field experiment during the exceptionally dry winter of 2017–2018, we found that seedling mortality was higher and growth of seedlings and adults were lower in unwatered than watered sites. Mortality of unwatered seedlings was higher in species with shorter seedling roots, and also in species with the correlated traits of small seeds, high seedling specific leaf area (SLA), and tall seedlings. Adult traits varied along an axis from short-stature, high SLA and foliar N, and early flowering to the opposite values, and were only weakly correlated with seedling traits and seedling mortality. No evidence was found for adaptive plasticity, such as longer roots or lower SLA in unwatered plants. Among these species, constitutive variation in seedling root length explained most of the variation in survival of a highly vulnerable life stage under winter drought. Selective loss of species with high adult SLA, observed in this community and others under drought stress, may be the byproduct of other correlated traits.
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Huanca-Nunez, Nohemi, Robin L. Chazdon, and Sabrina E. Russo. "Trait-Mediated Variation in Seedling Performance in Costa Rican Successional Forests: Comparing Above-Ground, Below-Ground, and Allocation-Based Traits." Plants 13, no. 17 (2024): 2378. http://dx.doi.org/10.3390/plants13172378.
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The interspecific relationship between functional traits and tree seedling performance can be inconsistent, potentially due to site-to-site or microsite variation in environmental conditions. Studies of seedling traits and performance often focus on above-ground traits, despite the importance of below-ground resource acquisition and biomass allocation to above versus below-ground functions. Here we investigate how varying environmental conditions across sites induce intraspecific variation in organ-level (above-ground, below-ground) and biomass allocation traits, affecting interspecific relationships between these traits and seedling performance. We analyzed trait expression for 12 organ-level and three allocation traits and their relationships with height growth (1716 seedlings) and mortality (15,862 seedlings) for 26 tree species across three sites along a forest successional gradient in Costa Rica. We found significant intraspecific differences across sites in all allocation traits, but only in three of seven above-ground and three of five below-ground organ-level traits. Allocation traits were better predictors of seedling performance than organ-level traits. Relationships between allocation traits and both growth and mortality varied among all sites, but for organ-level traits, only relationships with growth varied among sites. These results underscore that biomass allocation plays a key role in the earliest life stages of trees and that site-specific conditions can influence how functional traits mediate seedling establishment during succession.
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Wood, Katherine E. A., Richard K. Kobe, Inés Ibáñez, and Sarah McCarthy-Neumann. "Tree seedling functional traits mediate plant-soil feedback survival responses across a gradient of light availability." PLOS ONE 18, no. 11 (2023): e0293906. http://dx.doi.org/10.1371/journal.pone.0293906.
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1. Though not often examined together, both plant-soil feedbacks (PSFs) and functional traits have important influences on plant community dynamics and could interact. For example, seedling functional traits could impact seedling survivorship responses to soils cultured by conspecific versus heterospecific adults. Furthermore, levels of functional traits could vary with soil culturing source. In addition, these relationships might shift with light availability, which can affect trait values, microbe abundance, and whether mycorrhizal colonization is mutualistic or parasitic to seedlings. 2. To determine the extent to which functional traits mediate PSFs via seedling survival, we conducted a field experiment. We planted seedlings of four temperate tree species across a gradient of light availability and into soil cores collected beneath conspecific (sterilized and live) and heterospecific adults. We monitored seedling survival twice per week over one growing season, and we randomly selected subsets of seedlings to measure mycorrhizal colonization and phenolics, lignin, and NSC levels at three weeks. 3. Though evidence for PSFs was limited, Acer saccharum seedlings exhibited positive PSFs (i.e., higher survival in conspecific than heterospecific soils). In addition, soil microbes had a negative effect on A. saccharum and Prunus serotina seedling survival, with reduced survival in live versus sterilized conspecific soil. In general, we found higher trait values (measured amounts of a given trait) in conspecific than heterospecific soils and higher light availability. Additionally, A. saccharum survival increased with higher levels of phenolics, which were higher in conspecific soils and high light. Quercus alba survival decreased with higher AMF colonization. 4. We demonstrate that functional trait values in seedlings as young as three weeks vary in response to soil source and light availability. Moreover, seedling survivorship was associated with trait values for two species, despite both drought and heavy rainfall during the growing season that may have obscured survivorship-trait relationships. These results suggest that seedling traits could have an important role in mediating the effects of local soil source and light levels on seedling survivorship and thus plant traits could have an important role in PSFs.
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Pivatto, María Sosa, Guillermo Funes, Ana E. Ferreras, and Diego E. Gurvich. "Seed mass, germination and seedling traits for some central Argentinian cacti." Seed Science Research 24, no. 1 (2014): 71–77. http://dx.doi.org/10.1017/s0960258513000366.
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AbstractSeed size is one of the most important traits in the regenerative phase of a plant's life cycle; however, for cactus species the relationship of seed size and germination characteristics and seedling traits is still unclear. We studied the relationship between seed mass and germination and seedling characteristics in 17 cactus species from central Argentina, belonging to different genera and life forms. We measured seed mass, total seed germination, light requirements for germination and mean time to germination for these 17 cacti species; in addition, we recorded seedling size and shape in 15 species. To test light requirements we performed germination experiments under laboratory conditions at 25/15°C (day/night temperatures) and under light or dark conditions. We also calculated seedling volume by measuring seedling height and width. A shape index was obtained by dividing height by width (a value of 1 indicates ‘globose’ seedlings, whereas, as this value increases, seedlings become ‘columnar’). We found no significant relationship between seed mass and any of the germination characteristics considered. However, species with heavier seeds produced bigger seedlings, which were more cylindrical. Adult growth was not totally determined by seedling ‘growth form’, because some species that had globose seedlings were columnar at the adult stage.
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Yücedağ, Cengiz, Nebi Bilir, and Halil Barış Özel. "Phytohormone effect on seedling quality in Hungarian oak." Forest Systems 28, no. 2 (2019): e005. http://dx.doi.org/10.5424/fs/2019282-14604.
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Aim of study: to find out the effects of four phytohormones, including Indole Butyric Acid (IBA), Indole Acetic Acid (IAA), and Gibberellic acids (GA3, GA4) on seedling growth of Hungarian oak which has a natural distribution in the northwestern of Turkey.Area of Study: Mature acorns of Hungarian oak were collected from a natural stand in Zonguldak-Ereğli at northwestern region of Turkey.Material and Methods: Collected acorns of the species were pretreated with 300 ppm of each phytohormone for 24 hours and sown in Yenihan State Forest Nursery of Bartin, Turkey. Two years old bare-root seedlings were used for the measurements of seedling height, root collar diameter, stem, root and seedling fresh weights, and stem, root and seedling dry weights of two bare-root seedlings for each phytohormone treatment.Main results: Best performance of all studied seedling traits with the exception of root collar diameter was revealed in seedlings with IBA. In contrast, treatment of seeds with GA3 reduced all seedling traits apart from seedling height and root collar diameter. According to Dickson quality index, IBA was displayed to be the most beneficial phytohormone application for generating Hungarian oak seedlings with better mechanical resistance during transplanting.Research Highlights: IBA should be adopted in planting the seedlings of Hungarian oak for plantation activities.
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Rauf, Saeed, Hafeez Ahmad Sadaqat, and Iftikhar Ahmad Khan. "Effect of moisture regimes on combining ability variations of seedling traits in sunflower (Helianthus annuus L.)." Canadian Journal of Plant Science 88, no. 2 (2008): 323–29. http://dx.doi.org/10.4141/cjps07036.
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Seedlings traits provide a reliable and rapid technique for evaluating large numbers of genotypes for abiotic stresses. Experiments on sunflower were carried out under two moisture regimes in controlled conditions to study their modifying effect on phenotypic expression and combining ability of seedling traits such as root length (RL), shoot length (SL), root weight (RW), shoot weight (SW), root-to-shoot ratio (R:S), lateral root number (NLR), lateral root density (LRD), wilting rate index and recovery percent (R%), and their genotypic correlation with achene yield. Variation among breeding lines for relative decrease in the seedling traits under the moisture stress regime indicated their differences in moisture sensitivity. Genetic variation for all seedling traits was low over environments, but high within environments. Moisture regimes modified phenotype, ranking among parents, and combining ability of seedling traits. Relative contribution of specific combining ability to total variation decreased under the moisture stress regime for all root-based traits, with a corresponding increase in general combining ability due to either female, male or both. The moisture stress regime was favourable for the expression of additive genetic variability. All seedling traits except SL showed significant correlation with achene yield, which also signified their importance for improving achene yield under drought regimes. From the breeding point of view, R% and RW were more useful traits for evaluating genotypes for drought tolerance. Key words: Sunflower, seedling traits, genetic variability, drought tolerance
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SIMONS, R. G. "RELATIONSHIPS BETWEEN SEEDLING TRAITS AND MATURE PLANT YIELD IN ALFALFA." Canadian Journal of Plant Science 70, no. 1 (1990): 209–13. http://dx.doi.org/10.4141/cjps90-023.
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To compare some seedling traits with the yield of alfalfa plants when grown as a crop stand, 1000 individually weighed seeds of Beaver alfalfa (Medicago sativa L.) were germinated in a growth chamber in a greenhouse mix containing soil. The dates of emergence and expansion of the first trifoliolate leaf, the weight of the first trifoliolate leaf, and the height, shoot number, leaf number and yield 10 wk after seeding were all correlated with each other. The seedlings were transplanted in late summer in to a 15 × 15-cm grid in the field, simulating a crop stand. Individual plant yields were determined in each of the two succeeding years. The number of shoots present at the first harvest was determined in the seedling year. There was no difference in the mean weight of seeds which emerged and those which did not. The mature plant traits were all strongly correlated with each other (P > 0.001). Although the seed weight and seedling traits had low correlations with mature plant traits (r < 0.25), the top 10% of seedlings on the basis of the date of first trifoliolate leaf expansion or seedling yield exceeded the population (averaged over the two years) by more than 31 and 41% respectively.Key words: Alfalfa, Medicago, seedling, selection, yield
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Lahav, Emanuel, Eli Tomer, Shmuel Gazit, and Uri Lavi. "Performance of Avocado (Persea americana Mill.) and Mango (Mangifera indica L.) Seedlings Compared with Their Grafted Trees." Journal of the American Society for Horticultural Science 120, no. 2 (1995): 265–69. http://dx.doi.org/10.21273/jashs.120.2.265.
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Most fruit-tree breeding projects are based on selection of seedlings in regard to their performance. The selected seedlings are vegetatively propagated, usually by grafting. It is highly important for the breeder to know whether the performance of the grafted tree will resemble the performance of the original seedling. In this study the performance of avocado and mango seedlings was compared with that of their grafted duplicates. Significant differences were found in only 8 out of 36 avocado traits and 2 out of 10 mango traits. Significant seedling x graft interaction was detected in 10 other avocado traits. These differences were considered of no practical significance, since their magnitude was of minor importance for the breeder. The conclusion for avocado and mango breeders is that for most traits selection could be carried out on ungrafted seedlings.
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Nourmohammadi, Kazem, Davoud Kartoolinejad, Reza Naghdi, and Carol C. Baskin. "Effects of dormancy-breaking methods on germination of the water-impermeable seeds of Gleditsia caspica (Fabaceae) and seedling growth." Folia Oecologica 46, no. 2 (2019): 115–26. http://dx.doi.org/10.2478/foecol-2019-0014.
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AbstractVarious treatments can be used to break physical dormancy (PY, i.e. water-impermeable seed coat) of legume species, but the effects of these treatments on seedling growth are of great importance in the success of afforestation projects. Our aims were to determine the effects of 20 PY-breaking treatments on (1) germination of Gleditsia caspica (Caspian locust) seeds and (2) seedling growth. Five germination and nine seedling growth and morphological traits were studied. Immersion in concentrated sulfuric acid (98%) for 60 minutes was optimal for all germination traits and for all seedling traits except root length. After seed coat removal or treatment with sulfuric acid (for 45 to 120 minutes), 99–100% of the seeds germinated, but seedling growth traits after 5 months were significantly lower in the former than in the latter treatment. Other treatments (e.g., different periods of exposure to cold water, boiling water, and KNO3) did not significantly increase germination or improve seedling growth. Thus, despite incurring adverse environmental impacts, sulfuric acid treatments have the best potential to break seed dormancy and produce high-quality seedlings (in terms of shoot length, root and shoot mass, root area, leaf number and area and collar diameter) of Caspian locust.
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Mwando, Edward, Tefera Tolera Angessa, Yong Han, Gaofeng Zhou, and Chengdao Li. "Quantitative Trait Loci Mapping for Vigour and Survival Traits of Barley Seedlings after Germinating under Salinity Stress." Agronomy 11, no. 1 (2021): 103. http://dx.doi.org/10.3390/agronomy11010103.
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Seed germination and seedling establishment are the most critical stages in the barley (Hordeum vulgare ssp. vulgare L.) life cycle that contribute substantially to grain yield. These two phases are exposed to several forms of environmental stresses such as salinity due to high level of salt accumulation in the soil rhizosphere where seed germination takes place and seedlings emerge from. Previously, we have reported genotypic variability and independent QTLs associated with salinity tolerance at seedling and germination stages. However, genotypic studies on revival of a seedling germinating under salinity stress are yet to close the lack of information between germination and seedling stages. Here, we attempt to close the genetic gap by targeting early seedling survival traits in barley after germination under salinity (NaCl) stress and the various seedling vigour indices. Seedling vigour parameters formed the basis for Quantitative trait locus (QTL) linkage mapping in 103 Doubled Haploid (DH) lines of CM72/Gairdner population, and validated the phenotypic response using a selected diverse panel of 85 barley germplasm. The results indicate that 150 mM NaCl stress significantly reduced all the recorded phenotypic traits compared to 75, 90 and 120 mM NaCl. In both DH population and diversity panel barley germplasm, the highest percentage reduction was recorded in shoot length (65.6% and 50.3%) followed by seedling vigour index length (56.5% and 41.0%), while root length (28.6% and 15.8%) and root dry weight (29.3% and 28.0%) were least reduced when control was compared to150 mM NaCl stress treatment. Six QTLs containing 13 significant markers were detected in the DH population, 3 on chromosomes 1H, 8 on 3H and 2 on 4H with LOD values ranging from 3 to 8 associated with seedling survival traits under salinity stress. Three QTLs one on 1H and two on 3H with closely linked significant markers (Bmac0032, bPb-9418 and bPb-4741), (bPb-4576 and bPb-9624) and (bPb-3623, bPb-5666 and bPb-6383) for 1H and two on 3H respectively formed the regions with high possibility of candidate genes. A QTL on 3H flanked with markers bPb-4576 and bPb-9624 that were detected in more than one salinity survival trait and were closely linked to each other will form a basis for detailed studies leading to gene functional analysis, genetic transformation and marker assisted selection (MAS).
Dissertations / Theses on the topic "Seedling traits"
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Lammerant, Roel. "Impact of experimental soil moisture manipulation on tropical tree seedling demographic fates and functional traits." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-436103.
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In tropical regions, climate change is predicted to lead to increased drought frequency and intensity. The extent to which this will shift the functional diversity of tropical tree communities is unknown due to a limited understanding about the response of seedlings to variable soil moisture. We addressed this issue using an experimental approach in the Luquillo Experimental Forest, Puerto Rico. We exposed seedlings of eight tree species, representing different successional stages, to an experimental soil moisture gradient. We evaluated (1) How species mean trait values relate to species-specific demographic responses to drought, (2) How intraspecific variation in functional traits relates to a soil moisture gradient, (3) The extent to which demographic response to short-term experimental drought mirrored long-term demographic response of seedlings to natural variation in soil moisture. Growth and survival of species with more `conservative` functional strategies tended to be more sensitive to a change in soil moisture and more tolerant to drought compared to species with more `acquisitive` strategies. In addition, traits of individual seedlings within species varied with respect to soil moisture, suggesting a potential role for phenotypic plasticity in response to drought. Specifically, this response was significant for three species (Inga laurina, Guarea guidonia, Schefflera morototoni) and was primarily associated with relative carbon investment in leaves and roots. Species demographic responses to soil moisture in experimental and long-term studies were weakly positively correlated but more variables are at play under natural conditions, which partly decouples these responses. Overall, our results suggest that tree species with `conservative` functional strategies are likely to become more common under increasing drought frequency and intensity in the Luquillo Mountains of Puerto Rico. However, understanding the broader implications of our findings will require considering the effects of other disturbances, including hurricanes, which may have contrasting effects. Furthermore, intraspecific variation in functional traits is likely to influence how the seedlings of tropical tree species cope with drought.
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Lett, Signe. "Mosses as mediators of climate change : implications for tree seedling establishment in the tundra." Doctoral thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-130942.
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Alpine and arctic tree line expansion depends on the establishment of tree seedlings above the current tree line, which is expected to occur with climate warming. However, tree lines often fail to respond to higher temperatures. Other environmental factors are therefore likely important for tree seedling establishment. Above the tree line, establishing seedlings encounter existing vegetation such as bryophytes, which often dominate in arctic and alpine tundra. Bryophytes modify their environment in various ways and may mediate climate change effects on establishing tree seedlings, and with that tree line expansion. The aim of this thesis was to understand if and how the environment, in particular bryophytes, mediates the impact of climate change on tree seedling establishment at the alpine and arctic tree line. This was explored by reviewing literature on tree seedling establishment at alpine and arctic tree lines globally. In addition, tree seedling survival and growth of Betula pubescens and Pinus sylvestris were assessed experimentally. Here, individuals were planted into mono-specific mats of different bryophytes species and exposed to warming and different precipitation regimes. The literature review revealed that besides from temperature, tree seedling establishment is affected by a wide range of abiotic and biotic factors including water, snow, nutrients, light, disturbance and surrounding vegetation. Furthermore the review revealed that for example vegetation can change tree seedling responses to climate change. The experiments showed that especially tree seedling survival was adversely affected by the presence of bryophytes and that the impacts of bryophytes were larger than those of the climate treatments. Seedling growth, on the other hand, was not hampered by the presence of bryophytes, which is in line with earlier findings that seedling survival, growth and seed germination do not respond similarly to changes in environmental conditions. Moreover, we found several indications that vegetation above the tree line, including bryophytes, mediated tree seedling responses to warming and precipitation or snow cover. This thesis shows that temperature alone should not be used to predict future tree seedling establishment above the alpine and arctic tree line and that extrapolations from climate envelope models could strongly over or under estimate tree line responses to warming. This underlines the value of multi-factorial studies for understanding the interplay between warming and other environmental factors and their effects on tree seedling establishment across current tree lines.
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Salazar-Colqui, Bertha [Verfasser]. "Digital gene expression analysis during seedling development of complex traits in winter oilseed rape (Brassica napus L.) / Bertha Salazar-Colqui." Gießen : Universitätsbibliothek, 2015. http://d-nb.info/107979249X/34.
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Kinneen, Lois. "The effects of fragmentation on foliar defensive traits and insect herbivory rates in dipterocarp seedlings." Thesis, Griffith University, 2018. http://hdl.handle.net/10072/385011.
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Human-modified landscapes are ubiquitous and often made up of remnant fragments of natural ecosystems nested within an agricultural or urban matrix. Understanding how species are affected by habitat degradation is a central issue in biodiversity research, yet investigations into the impacts on key ecological interactions have not kept pace. Gaining insight into the responses of ecological processes is vital in order to maximise biodiversity conservation and develop sustainable management practices in a changing world. Herbivory is a fundamental ecosystem process as it mediates the transfer of energy between primary production and higher trophic levels. In tropical rainforests herbivory is primarily carried out by insects.
Here, I investigate how leaf damage changes over time by carrying out repeated measures of herbivory following fragmentation. In doing so, I build upon previous ‘snapshot’ studies which have primarily quantified leaf damage at single points in time. An experiment was established within a large-scale manipulation experiment: the Stability of Altered Forest Ecosystems (SAFE) project in the Malaysian state of Sabah, within Borneo. I used seedlings of two species of endemic Dipterocarpaceae as the study system for two main reasons. Firstly, seedlings represent the most vulnerable life stage in a tree’s life cycle, and therefore insect herbivory may be a major determinant of their growth and survival. Secondly, not only do members of the family Dipterocarpaceae dominate in lowland tropical rainforests of Southeast Asia, most are economically valued for their timber and are consequently under pressure from logging which is leading to conservation concern. Five hundred and seventy-six seedlings were planted in 12 recently isolated one hectare fragments and 12 continuous forest control sites. Eight of these control sites were located in an area of continuous forest estimated to be over one million hectares north of the experimental landscape of the SAFE project. Four further control sites were established in a virgin jungle reserve which is over 2,200 hectares and located to the south-west of the experimental area. All leaves were scanned in situ on six occasions over two field seasons (May- October) in 2015 and 2016. At the end of the experiment, traits analyses were performed to quantify three common metrics of leaf defence: total phenolic content, acid detergent fibre and leaf strength.
Through this experiment I addressed the following aims; (1) to determine the initial effects of fragmentation on rates of leaf damage, (2) to investigate whether bottom-up control of herbivory was altered by fragmentation through changes in foliar defence, and (3) to assess whether responses were shared among study species or were instead individualistic.
I also use data from a key published monograph to create species interaction networks between lepidopteran caterpillars and their known host plants in tropical Asia, with the aim of exploring the importance of members of the Dipterocarpaceae for insect herbivores.
I found some evidence that herbivory is disrupted by fragmentation, with both species exhibiting lower levels of herbivory in fragments. Forest type was an important predictor of patterns of leaf area loss in this experiment, but overall differences between herbivory in fragments and control sites were not significant. Instead, herbivory was best explained by seedling traits, and predictors of leaf area loss varied between species indicating species-specific responses. Relaxation of phytochemical defensive traits was also detected in forest fragments, perhaps due to decreased levels of herbivory. A reduction in phytochemical defence may imply an increased vulnerability of seedlings in forest fragments which translates to differences in herbivore damage over time.
I highlight the importance of repeated measures experiments when investigating a complex and dynamic ecological process such as herbivory, and propose long term monitoring to fully understand the effects of forest fragmentation. The results of this thesis contribute to understanding the effects of fragmentation on insect herbivory, which remain uncertain, and provide evidence of the extent to which this key ecosystem process is disrupted due to anthropogenic habitat modification<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Environment and Sc<br>Science, Environment, Engineering and Technology<br>Full Text
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Bertoncello, Ricardo. "Restauração ecológica e processos estruturadores de comunidades vegetais." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/41/41134/tde-28092016-102207/.
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Interações interespecíficas são consideradas importantes forças estruturadoras da vegetação. Enquanto a competição aparentemente prevalece em ambientes com menor estresse abiótico, a facilitação tende a aumentar em importância em ambientes de maior estresse. Consequentemente, é esperado que a facilitação desempenhe um papel importante em áreas tropicais degradadas, nas quais as condições abióticas, envolvendo altos níveis de irradiação, temperatura e evapotranspiração, são muito distintas das condições ótimas para a maioria das espécies florestais. Além disso, face à complexidade dos processos estruturadores de comunidades florestais tropicais altamente diversas, os ecólogos têm percebido a necessidade de simplificação. Um caminho promissor para isso é por meio do uso de características funcionais, que podem ser medidas para qualquer espécie e comparadas em diferentes sistemas e locais. No entanto, em áreas degradadas ainda é incerta a relação entre as características funcionais e o desempenho das espécies. Neste contexto, planejamos um projeto de restauração na planície costeira do sudeste brasileiro para comparar o crescimento e a sobrevivência de mudas de árvores plantadas em diferentes densidades (sistema isolado ou sistema agregado) em um experimento fatorial com adição de nutrientes. No primeiro capítulo analisamos a sobrevivência, altura, diâmetro ao nível do solo e projeção da copa de 4.132 mudas de 19 espécies de diferentes classificações sucessionais, durante um período de 18 meses. Usamos modelos de efeitos mistos para analisar a relação entre o desempenho de espécies e os tratamentos e selecionamos os melhores modelos utilizando o critério de informação de Akaike (AIC). Verificamos uma maior sobrevivência nos sistemas agregados para as espécies não-pioneiras, indicando o predomínio do processo de facilitação. Em contrapartida, constatamos um menor crescimento em diâmetro nos sistema de plantio agregado, indicando o predomínio de competição. A adição de nutrientes não afetou a sobrevivência nos sistemas agregados, mas, surpreendentemente, teve um efeito negativo sobre as plantas isoladas. Além disso, a adição de nutrientes teve um efeito positivo sobre crescimento, diâmetro e projeção da copa nos sistemas de plantio agregado (indicando a redução da competição), especialmente para espécies pioneiras. Uma vez que o estabelecimento de espécies não-pioneiras em áreas degradadas pode ser bastante difícil, a facilitação para a sobrevivência dessas espécies em sistemas agregados pode ser utilizada como instrumento para melhorar os modelos de restauração. No segundo capítulo utilizamos algumas características funcionais que são facilmente mensuráveis para investigar sua relação com o crescimento e sobrevivência das mudas. Além disso, testamos o efeito das interações interespecíficas na relação das características funcionais com o desempenho das plantas. Para espécies pioneiras, uma maior área foliar específica (SLA - Specific leaf area), foi relacionada com uma maior taxa de sobrevivência. Entretanto, ao considerarmos as relações interespecíficas (sistemas agregados), maior SLA foi relacionada com uma menor taxa de sobrevivência. Em geral, as características funcionais explicaram apenas parcialmente o desempenho de mudas no contexto de restauração de áreas degradadas. Nosso trabalho contribuiu para a discussão sobre o potencial da aplicação prática da abordagem funcional na escolha das espécies para a recuperação de áreas degradadas. O caráter manipulativo da restauração ecológica baseada no plantio de mudas amplia as perspectivas para implementar experimentos que visem testar novas hipóteses em ecologia e refinar modelos de restauração<br>Interspecific interactions are considered to be important structuring forces in early successional vegetation. Whereas competition seems to prevail in less severe environments, facilitation tends to increase in importance in harsh environments. Hence, facilitation is expected to play an important role in degraded tropical areas with high irradiance, heat loads, and evapotranspiration, where conditions are far from optimum for most forest species. Moreover, in order to understand complex structuring process of high diverse tropical forests, ecologists have realized the need for simplification. A promising way to do that is through the use of functional traits, which can be measured for any species and compared in different systems and different locations around the world. However, in these conditions, little is known about the role of species interaction on the relation of functional traits and species performance. In this scenario, we planned a restoration project on the southeastern Brazilian coastal plain to compare growth and survival of tree seedlings planted at two densities (isolated or aggregated) in a factorial experiment with nutrient addition. In the first chapter we analyzed survival, height, ground level diameter, and crown projection of 4,132 saplings from 19 species that ranged along a successional gradient, over an 18-month period. We used mixed-effect models to analyze the relationship between species performance and treatments, and Akaike\'s information criterion (AIC) to select the models. The best model showed higher survival in aggregated plantations (indicating facilitation) for non-pioneer species. In contrast, we found lower diameter growth in aggregated plantation (indicating competition). Fertilizer addition did not affect survival in clusters, but, surprisingly, it had a negative effect on isolated plants of both pioneer and non-pioneer species. On the other hand, fertilizer addition had a positive effect on diameter and crown projection growth in aggregated plantations (reducing competition), especially for pioneer species. Thus, whether facilitation or competition was the predominant interaction depended on the response analyzed. We concluded that, as establishment of non-pioneer species in disturbed sites can be challenging, restoration designs could take advantage of higher survival rates in clusters and use resource addition to ameliorate growth and decrease competition for limited resources. In the second chapter we used the core simple-measurable traits to investigate whether functional traits were related to growth and survival and whether there was a difference in the effect of the functional traits on plant performance of isolated individuals or of individuals subjected to interaction with neighbors. Our main findings were that for pioneer species, the greater the specific leaf areas (SLA), the greater the survival rates, but, under aggregated conditions, the greater the SLA the lower the survival rates. However, functional traits only partially explained saplings performance in a restoration context and more research is needed to understand its role in predicting seedlings outcomes, especially considering the potential applicability of this methodological approach. The manipulative character of ecological restoration broadens perspectives to use experiments to generate and test new hypotheses in ecology and to refine restoration models
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Berry, Christopher J. J. "Post-dispersal seed predation in a conifer-broadleaf forest remnant : the importance of exotic mammals." Lincoln University, 2006. http://hdl.handle.net/10182/666.
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Despite extensive international acceptance of the critical role of mammalian post-dispersal seed predation in many plant communities, in New Zealand we have limited knowledge of these predators’ influence on plant recruitment in our forests. The principle objective of my thesis was to determine the importance of exotic mammals as post-dispersal seed predators in a New Zealand conifer-broadleaf forest remnant. To address this goal, I used a series of field-based experiments where the actions of different post-dispersal seed predators were separated by wire-mesh exclosures. My study was conducted at Mount Peel Forest Park Scenic Reserve, South Canterbury, New Zealand. Being a human modified conifer forest currently dominated by broadleaf species, it is typical of forest remnants in New Zealand. This presented an opportunity to study a wide range of both potential post-dispersal seed predators and broadleaf tree species. My findings indicate that exotic mammals are not only post-dispersal seed predators at Peel Forest, but are responsible for the majority of post-dispersal predation events observed. Ship rats (Rattus rattus) were the dominant post-dispersal seed predators, while brushtail possums (Trichosurus vulpecula), house mice (Mus musculus) and native invertebrates were also important post-dispersal seed predators for several tree species. Through use of time-lapse video and cafeteria experiments I found that exotic mammalian seed predators, when compared to native invertebrate seed predators, preyed upon larger-seeded plant species and were responsible for considerable seed losses of several tree species. However, exotic mammalian seed predators do share several foraging characteristics with native invertebrate seed predators, as predators foraged in similar habitats and responded in a similar way to changes in seed density. In investigating if post-dispersal seed predation by mammals had a flow-on effect to plant recruitment, I observed natural seedling densities at Peel Forest were significantly higher in the absence of mammalian seed predators, but I found no evidence that the presence of mammals significantly altered the overall species richness. At the community level, I did not find an interaction between habitat and exotic mammals, however I present evidence that for individual plant species a significant mammal : habitat interaction occurred. Consequently, even though my cafeteria experiment implied there was no significant difference in the overall amount of seed preyed upon within different habitats, the less favourable microsite conditions for germination under an intact continuous canopy allows mammals to exacerbate habitat-related patterns of seed mortality and have a noticeable effect on seedling establishment. In an effort to validate the use of manipulative experiments to predict the long-term effect of post-dispersal seed predation on plant dynamics, I attempted to link results of my cafeteria experiment with observed seedling abundance at Peel Forest. Seven tree species were used in this comparison and a strong correlation was observed. This result shows that the level of post-dispersal seed predation determined in the cafeteria experiment provided a good predictor of the effect of mammalian post-dispersal seed predation on seedling establishment. To fully gauge the impact of mammalian post-dispersal seed predators on seedling establishment, the relationship between these seed predators and the type of recruitment limitation experienced by a plant species was also investigated. By using a combination of seed addition, plot manipulations and seed predator exclusion I was able to investigate this relationship. I found evidence that seed limitation at Peel Forest is positively correlated with seed size, and that while mammalian post-dispersal seed predators can further reduce plant recruitment of plant species experiencing seed limitation, the influence of mammals in determining plant recruitment was limited for plant species experiencing microsite limitation. My study has proven that exotic mammals are now the dominant post-dispersal seed predators at Peel Forest, the amount of seed preyed upon varies among plant species, and post-dispersal seed predation by mammalian species can lead to differences in seedling richness and abundance. I proved that the influence of exotic mammals on seedling establishment is also linked to habitat structure and recruitment limitations. When combined these observations suggest that exotic mammalian post-dispersal seed predators may play an important role in determining landscape abundance and distribution of plants at Peel Forest.
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Thomas, Dana J. "Morphological Tradeoffs of American Chestnut (Castanea Dentata) and Co-Occurring Hardwoods in Varying Nutrient and Light Regimes." Miami University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=miami1134161439.
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Thomas, Dana Jeanette. "Morphological tradeoffs of American chesnut (Castanea dentata) and co-occurring hardwoods in varying nutrient and light regimes." Connect to this document online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1134161439.
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Thesis (M.S.)--Miami University, Dept. of Botany, 2005.<br>Title from first page of PDF document. Document formatted into pages; contains [1], v, 38 p. : ill. Includes bibliographical references (p. 35-38).
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Vidaller, Christel. "Quels facteurs limitent l’installation de Brachypodium retusum : une espèces clé pour la restauration écologique des steppes méditerranéennes ?" Thesis, Avignon, 2018. http://www.theses.fr/2018AVIG0349/document.
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Le brachypode rameux (Brachypodium retusum) est une espèce herbacée pérenne qui domine les pelouses sèches de Méditerranée occidentale. Dans notre zone d’étude du Sud de la France, la recolonisation spontanée est très faible après perturbation du sol. Cette observation ne correspond pas aux résultats d'études menées dans d'autres régions montrant une capacité de colonisation élevée. L'objectif principal de cette thèse était donc de tester les différentes hypothèses pouvant expliquer les différents patrons de colonisation.Dans un premier chapitre, nous avons testé si ces différents patrons de colonisation résultent d'une différenciation génétique entre les populations. Des marqueurs AFLP ont été utilisés pour analyser la structure génétique de 17 populations de Méditerranée occidentale dont la différenciation neutre entre populations. Dans un sous-échantillon de 13 populations françaises, la différenciation de traits phénotypiques sous sélection a été testée dans un jardin commun et comparée à la différenciation neutre. Dans le deuxième chapitre, nous présentons une étude sur la différenciation adaptative des traits phénotypiques et avons testé une potentielle réponse différentielle à la manipulation de facteurs environnementaux clés. Les deux derniers chapitres de la thèse ont analysé les facteurs environnementaux qui limitent la recolonisation in situ, indépendamment du génotype ou de la population. Dans le troisième chapitre, nous avons testé l’effet du pâturage et du feu sur le recouvrement végétatif ainsi que sur la reproduction sexuée de B. retusum installé. Enfin, dans le quatrième chapitre, nous avons mesuré l’effet de l’arrosage initial et du pâturage sur l’installation de plantules transplantées initialement germées en serre et de plantules issues de semis in situ. Nos résultats ont montré que les populations de B. retusum sont génétiquement différenciées pour les marqueurs neutres mais également pour les traits phénotypiques. Cette différenciation est supérieure à la dérive seule et suggère une adaptation aux conditions environnementales, en particulier aux températures estivales et à la fréquence du gel en hiver. Une réponse différentielle à la manipulation expérimentale de facteurs environnementaux (sol, pâturage, humidité du sol) a confirmé le caractère adaptatif de la différenciation génétique. Les expériences in situ ont montré que le feu a un effet positif sur la reproduction de B. retusum et sur la communauté végétale associée, alors que son recouvrement végétatif n’était pas supérieur à la moyenne de la communauté. L'exclusion du pâturage pendant deux saisons n'a eu d'incidence sur aucun des paramètres mesurés chez les populations adultes. L'arrosage initial a affecté l’installation des plantules au cours de la première saison. Au cours de la deuxième saison, l'effet seul de l’arrosage n'était pas significatif, cependant son effet est resté positif sur la survie uniquement dans les parcelles pâturées. Le pâturage, au début du cycle de vie de B. retusum, a eu un effet négatif sur le recrutement et la croissance des plantules. En conclusion, la différenciation adaptative entre les populations peut avoir contribué aux différences régionales en termes de capacité de colonisation et doit être prise en compte lors du ciblage des populations sources pour l'introduction de plantes en restauration écologique. La réponse positive de B. retusum a indiqué que le feu était une force sélective importante dans le passé qui pourrait être utilisée pour favoriser l'espèce et la communauté végétale associée dans des opérations de conservation et de restauration. L'exclusion du pâturage à court terme est tolérée par les populations adultes de B. retusum, mais l'abandon à long terme entraîne une diminution de son recouvrement par rapport aux graminées pérennes à croissance rapide<br>Ramose false brome (Brachypodium retusum) is a perennial herbaceous species that dominates dry grasslands of the Western Mediterranean. In our southern French study area, spontaneous re-colonisation is very low after soil disturbance. This observation does not correspond to the results of studies from other regions showing a high colonisation capacity. The major objective of this PhD thesis was to test different hypotheses potentially explaining the different colonisation patterns.In the first chapter, we tested whether these different colonisation patterns are the result of genetic differentiation among populations. AFLP markers were used to analyse genetic structure including neutral population differentiation in 17 Western Mediterranean populations. In a sub-sample of 13 French populations, differentiation in phenotypic traits under selection was tested in a common garden and compared to neutral differentiation. In the second chapter, we present a study on adaptive differentiation in phenotypic traits testing a potentially differential response to the manipulation of key environmental factors. The last two chapters of the PhD analysed environmental factors that limit re-colonisation in the field independent of genotype or population. In the third chapter, we tested the effect of grazing and fire on vegetative recovery as well as on sexual reproduction of established B. retusum and in the fourth chapter we measured the effect of initial watering and grazing on the establishment of transplanted seedlings pre-grown in a greenhouse and of field-sown seedlings.Our results showed that populations of B. retusum are genetically differentiated in neutral markers but also in phenotypic traits. This differentiation is superior to drift alone and suggests adaptation to environmental conditions, particularly to summer temperature and winter frost frequency. A differential response to experimental manipulation of environmental factors (soil, pasture, soil moisture) confirmed the adaptive character of genetic differentiation. The field experiments showed that fire has a positive effect on B. retusum reproduction and on the associated community whereas vegetative recovery was not higher than community average. Two seasons of grazing exclosure did not affect any of the measured parameters in adult populations. Initial watering affected seedling establishment in the first season. In the second season, the watering main effect was not significant but interestingly the effect remained positive on survival in grazed plots whereas no such effect was observed in exclosures. Grazing in early life cycle stages of B. retusum had a negative effect on seedling recruitment and growth.In conclusion, adaptive differentiation between populations may have contributed to regional differences in colonisation capacity and needs to be taken into account in targeting source populations for plant introduction in ecological restoration. The positive response of B. retusum indicated that fire was an important selective force in the past which may be used to favour the species and its associated plant community in current conservation and restoration management. Short-term grazing exclosure is tolerated by mature B. retusum populations but long-term abandonment results in a decrease of cover relative to high-growing perennial grasses. In early stages of seedling establishment grazing should be avoided to guarantee introduction success - or grazing stress needs to be compensated by watering
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Stone, Philippa Mary Rose. "Response of rainforest trees to climate warming along an elevational gradient in the Peruvian Andes." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31560.
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The tropical rainforests of the Peruvian Andes are some of the most biodiverse and most vulnerable to climate warming in the world. The Andes are predicted to experience substantial increases in warming of between +2 °C to +5 °C by the end of the century, in addition to an increases in the frequency of high temperature extremes, drought and flood events. The response of these forests to climate change over the next century has global relevance, due to the high levels of endemic species present and the potential role these areas will play as refugia for lowland species. Despite this, the response of tropical montane forests (TMCFs) to climate change remains under-studied. Our current understanding of how Andean species will respond to climate change is based on studies of past compositional changes. Upslope shifts in plant communities of approximately 1.2 - 2.0 m·y-1 have been observed along elevational gradients within Central and South America over the last decade. Based on these migration rates, it has been estimated that the majority of communities will lag behind increases in temperature by 5.5 °C by the end of the century. The implications of this for populations at the trailing range edge is unclear, due to a lack of mechanistic data concerning the acclimatory limits of rainforest species. When faced with rapid warming plant species will need to rapidly adapt, acclimate or migrate in order to survive. In the case of Andean species, migration rates may not be sufficient for a species to remain within its optimal thermal niche and adaptive responses will likely be too slow to be effective, hence individuals will have to acclimate in situ to prevent a decline in performance. The acclimatory ability of species can be quantified by measuring changes in performance, leaf physiology and anatomy in response to experimental manipulations of climate, however such studies are rare within the tropics. Here we carried out a seedling transplant experiment, utilising an extensive 400-3500 m asl elevational gradient in the Peruvian Andes, to simulate climate warming and upslope migration of tree seedlings under real-world conditions. To provide context for the transplant study, natural variation in leaf anatomical traits and physiological stress were explored for twelve species belonging to lowland (LF), mid-elevation (LMF) and tropical montane cloud forest communities. Adults and seedlings from the centre and furthest-most extent of each species' elevational range were studied and compared. Seedlings of each elevational forest community were transplanted downslope and upslope of their local elevational range by the equivalent of ±2 °C and ±4 °C in mean annual temperature. The experiment followed the transplanted seedlings of eleven species over a one year period, monitoring survival, growth and physiological stress (Fv/Fm) of individuals. The acclimatory ability of a subset of these species was quantified by measuring changes in photosynthetic capacity (Vcmax and Jmax), respiratory capacity (Rd) and anatomical traits (Na, Pa, LMA, LDMC) in response to transplantation. The results showed that within the natural population there was little evidence of leaf trait acclimation to elevational shifts in climate, but also little evidence of physiological stress at the trailing range edge. There were however differences in the leaf trait strategies employed by each elevational community, increasing in abiotic stress-tolerance with elevation. Physiological stress was greatest in the seedling population and, unlike the adult population, increased slightly at the trailing edge. This indicated that seedlings were more vulnerable to warming than their adult counterparts and at mid-elevations TMCF seedlings were more vulnerable than LMF seedlings. Seedling survival and growth declined in response to transplantation away from the home elevation for the majority of species, with upslope declines as a result of abiotic limitations, and downslope declines due to biotic limitations. All seedlings were found to be able to acclimate their respiratory capacity in response to transplantation, however this was not the case for photosynthetic capacity. LMF species performed significantly better than TMCF seedlings with transplantation, demonstrating a greater acclimatory capacity for photosynthesis. LMF species were able to adjust Jmax in order to maintain rates at ambient temperatures, but were not able to upregulate Vcmax upslope, whereas TMCF species were not able to respond in either transplant direction. Overall, these findings suggest that under moderate warming scenarios LMF species will have a competitive advantage over TMCF species at mid-elevations, gradually expanding their range into TMCF species' habitat over the next century. As a result of this and due to the slow pace of upslope migration, we predict that TMCF species will undergo range retractions and possible extinctions. The speed of this response will be determined by the trajectory of future warming and the frequency of extreme climatic events.
Books on the topic "Seedling traits"
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Peter, Rotach. Multivariate patterns of genetic variation in ponderosa pine (Pinus ponderosa Dougl. ex Laws.), based on allozyme scores and seedling quantitative traits. 1997.
Find full textBook chapters on the topic "Seedling traits"
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Quilloy, Fergie Ann, Benedick Labaco, Carlos Casal, and Shalabh Dixit. "Crop Establishment in Direct-Seeded Rice: Traits, Physiology, and Genetics." In Rice Improvement. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-66530-2_6.
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AbstractThe changing climate and water availability strongly affect the current state of agricultural production. While the global temperature rises, the occurrence of extreme climatic conditions becomes erratic. This current scenario has driven the development of rice varieties and cultivation practices that require less water and favor mechanization. Although puddled transplanted rice has been more widely used in the past, direct seeding has been gaining popularity in recent years, especially due to its water- and labor-saving features. This technique allows full crop establishment from seeds that were directly sown in the field, thus avoiding puddling, transplanting, and maintaining standing water. Consequently, it offers promising positive environmental effects including decreasing the release of greenhouse gases and increasing water-use efficiency. Historically, rice varieties bred for transplanting are also used in direct seeding, which limits the maximum yield potential of field trials. The success of direct seeding relies strongly on the development of rice varieties with robust crop establishment. Anaerobic germination, seed longevity, and early seedling vigor are the key traits required to achieve this. This chapter expounds on the physiology, molecular mechanisms, genetics, and relevance of the enumerated traits for direct seeding. A brief discussion of breeding for rice varieties with improved germination under direct seeding is also provided.
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Garcia, A., W. G. Morgan, M. D. Hayward, and H. Thomas. "Seedling Vigour, Agronomic Traits, and Isozyme Markers in Backcrosses Lolium Perenne X Festuca spp." In Developments in Plant Breeding. Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0966-6_47.
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Díaz Vélez, M. Celeste, Ana E. Ferreras, and Valeria Paiaro. "Seed dispersal interactions promoting plant invasions." In Plant invasions: the role of biotic interactions. CABI, 2020. http://dx.doi.org/10.1079/9781789242171.0090.
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Abstract Animal dispersers are essential for many non-native plants since they facilitate seed movement and might promote seed germination and seedling establishment, thereby increasing their chances of invasion. This chapter reviews the published literature on seed dispersal of non-native plant species by native and/or non-native animals. The following questions are addressed: (i) Are interactions between non-native plants and their animal dispersers evenly studied worldwide? (ii) Which are the distinctive traits (i.e. geographical origin, life form, dispersal strategy and propagule traits) of non-native plants that are dispersed by animals? (iii) Which are the most studied groups of dispersers of non-native plants around the world? (iv) Does the literature provide evidence for the Invasional Meltdown Hypothesis (non-native plant-non-native disperser facilitation)? (v) What is the role of animal dispersers at different stages of the non-native plant regeneration process? Our dataset of 204 articles indicates that geographical distribution of the studies was highly heterogeneous among continents, with the highest number coming from North America and the lowest from Asia and Central America. Most of the non-native plants involved in dispersal studies were woody species from Asia with fleshy fruits dispersed by endozoochory. More than the half of the animal dispersal agents noted were birds, followed by mammals, ants and reptiles. The dominance of bird-dispersal interactions over other animal groups was consistent across geographical regions. Although most of the studies involved only native dispersers, interactions among non-native species were detected, providing support for the existence of invasional meltdown processes. Of the total number of reviewed articles reporting seed removal, 74% evaluated seed dispersal, but only a few studies included seed germination (35.3%), seedling establishment (5.4%) or seed predation (23.5%). Finally, we discuss some research biases and directions for future studies in the area.
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Siahaan, Febrina Artauli. "Differences in Leaf Functional Traits of Canarium vulgare Leenh. Between Two Growth Stages: Mature vs. Seedling." In Advances in Biological Sciences Research. Atlantis Press International BV, 2023. http://dx.doi.org/10.2991/978-94-6463-166-1_48.
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Gomez-Pando, Luz, Jesus Bernardo-Rojas, Denisse Deza-Montoya, Martha Ibañez-Tremolada, and Enrique Aguilar-Castellanos. "Mutation induction to improve quinoa (Chenopodium quinoa) resistance to downy mildew (Peronospora variabilis)." In Mutation breeding, genetic diversity and crop adaptation to climate change. CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0019.
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Abstract Quinoa is an important crop due to its nutritional characteristics (better than cereals) and its tolerance to abiotic stresses. However, various factors such as high susceptibility to diseases, especially downy mildew caused by Peronospora variabilis, limit its agricultural performance. Genetic improvement of quinoa could reduce the need to use fungicides for this crop and maintain the organic quality of Peruvian production in small-scale farms. Seeds of var. 'Amarilla Marangani', irradiated with 150 and 250 Gy of gamma-rays (<sup>60</sup>Co), were evaluated in two experimental locations in Peru: coastland at La Molina and highland at Huancayo. Resistance to downy mildew and other agricultural traits in the M<sub>3</sub> and M<sub>4</sub> generations was studied. In both locations, downy mildew was observed in susceptible plants under natural infection, from the seedling stage to plant maturity. At the coastland site, six mutants with 30% leaf infection were obtained in the progeny of plants exposed to 150 Gy. Five additional mutants with 40% leaf infection were found in the progeny of plants exposed to 250 Gy. In the highland trial, only seven lines were identified with 30% severity (foliar area with symptoms) among the plants from the 150 Gy experiment. The parent materials showed 70-80% disease severity. Mutant lines with quantitative resistance and tolerance to downy mildew, high yield potential, reduced duration, shorter plant height, altered inflorescence shape and grain colour mutations were selected from both doses. This study showed that quantitative resistance and tolerance to downy mildew could be obtained in quinoa and this resulted in increased grain yields.
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Feil, B., R. Thiraporn, G. Getsler, and P. Stamp. "Root traits of maize seedlings—indicators of nitrogen efficiency?" In Genetic Aspects of Plant Mineral Nutrition. Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-2053-8_15.
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Xiang, Chunyang, Jin Du, Peipei Zhang, Gaoyi Cao, and Dan Wang. "Preliminary Study on Salt Resistance Seedling Trait in Maize by SRAP Molecular Markers." In Lecture Notes in Electrical Engineering. Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-45657-6_2.
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Álvarez-Sánchez, Javier, Irene Sánchez-Gallen, and Patricia Guadarrama. "Analyses of Ecophysiological Traits of Tropical Rain Forest Seedlings under Arbuscular Mycorrhization: Implications in Ecological Restoration." In Soil Biology. Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-95894-9_18.
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Basu, Sudipta, and Steven P. C. Groot. "Seed Vigour and Invigoration." In Seed Science and Technology. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-5888-5_4.
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AbstractSeed vigour is an important aspect of seed quality. It is a quantitative trait which is responsible for overall seed performance in terms of rate and uniformity of seed germination, seedling growth, emergence ability under unfavourable environments and post storage performance. Seed vigour is controlled by genetic factors, initial seed quality, production environments, harvesting and storage conditions. Seed vigour tests provide a more sensitive index of seed performance per se than the germination test. Efforts have been focused on developing novel or improving existing methods of vigour estimation in different crops. The vigour tests are tools routinely used for in-house seed quality control programs, especially for field and vegetable crops. Some treatments can improve seed vigour, although the treatment effects are more evident under sub-optimum than optimum growing conditions. This chapter deals with different aspects of seed vigour and its effects on plant growth and discusses physiological and biochemical parameters to understand underlying mechanisms.
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Nautiyal, P. C., K. Sivasubramaniam, and Malavika Dadlani. "Seed Dormancy and Regulation of Germination." In Seed Science and Technology. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-5888-5_3.
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AbstractSeed germination and dormancy are vital components of seed quality; hence, understanding these processes is essential for a sound seed production system. The two processes are closely interrelated and regulated, both by genetic as well as environmental factors. While dormancy provides an inherent mechanism aimed at the survival of the plant species to withstand adverse external conditions by restricting the mature seed from germinating, the ability of the dehydrated seed to remain viable and produce a vigorous seedling upon hydration under favourable conditions is the key to the survival and perpetuation of the plant species. In addition, quality seed is expected to result in timely and uniform germination under favourable field conditions after sowing to establish a healthy crop stand. Therefore, in seed technology, dormancy is not considered a desirable trait in the seed lots used for sowing. Thus, to achieve the highest germination percentage, understanding the factors controlling these two interlinked and contrasting processes is vital. In seed testing and seed trade, knowledge of seed germination and dormancy is needed for a reliable assessment of seed quality and its planting value, and to make right decisions. Though much is yet to be understood, the present status of knowledge on these aspects has made significant advances, especially in genetic control, molecular mechanism, and physiological and environmental factors influencing germination and dormancy. The information compiled in this chapter may help the seed technologists in developing new methods for breaking dormancy and testing germination,
Conference papers on the topic "Seedling traits"
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Pavlović, Nenad, Vladimir Crepuljarević, Jelena Mladenović, et al. "INFLUENCE OF DIFFERENT SUBSTRATES ON THE QUALITY OF PEPPER SEEDLINGS (Capsicum annuum L.)." In 2nd International Symposium on Biotechnology. Faculty of Agronomy in Čačak, University of Kragujevac, 2024. http://dx.doi.org/10.46793/sbt29.12np.
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The paper shows the influence of different substrates on the quality of pepper seedlings. Based on the obtained results, it can be concluded that different substrates had an impact on the biological-morphological characteristics of pepper seedlings. The best results for most of the analyzed biological-morphological characteristics of pepper seedlings, according to the results obtained by the experiment, are related to the substrates “Glistenjak“, „K-Potgrond H-Black 90%“ and “K-TS1-White 100%”, while the worst results were achieved on the examined substrates of “Coconut Cube”. The mean value for all traits was recorded on the substrate “K- Seedling substrat”.
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Marii, Liliana, Larisa Andronic, Marionela Sahanovschih, and Angela Ionascu-Urechii. "The effects of high temperature at different ontogenetic stages on some phenotypic indices in tomato plants." In Conferința științifică națională cu participare internațională "Integrare prin cercetare și inovare", dedicată Zilei Internaționale a Științei pentru Pace și Dezvoltare. Moldova State University, 2025. https://doi.org/10.59295/spd2024n.17.
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The study aims to investigate the tomato plants response to heat stress applied at the germination and seedling stages, evaluating certain phenotypic parameters in order to highlight possible particularities associated with adaptability to unfavorable environmental conditions. The research included three tomato genotypes with determined stress reactions that were designed into four variants: optimal-optimal, optimal-stress, stress-optimal, and stress-stress. The application of high temperatures at the germination stage significantly affects the subsequent development of tomato plants, resulting in a decrease in the average values of morphological traits compared to optimal conditions variants. The effects of heat stress vary depending on the genotype and the analyzed trait, with certain variants exhibiting specific vulnerabilities. Variance analysis shows that the temperature conditions and the stress application scheme significantly contribute to the variability of morphological traits, with stress at the germination stage having a dominant impact on architectural traits of plants, while genotype becomes the major influencing factor at the seedling stage. The results emphasize the importance of plant adaptability to thermal stress at different developmental stages.
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Ozolina, Sintija, Uldis Zaimis, and Andrejs Kukuskins. "Development and application of biodegradable wheat straw and carrageenan composite in agriculture." In 23rd International Scientific Conference Engineering for Rural Development. Latvia University of Life Sciences and Technologies, Faculty of Engineering and Information Technologies, 2024. http://dx.doi.org/10.22616/erdev.2024.23.tf171.
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Environmental concerns in the long run have led the public to develop alternative materials that could be used in agriculture. The development and application of carrageenan and wheat straw biodegradable composite in agriculture is the main focus of this study. This composite is crafted to tackle the environmental repercussions linked with traditional agricultural materials. The manufacturing procedure encompasses the extraction and treatment of wheat straw fibres, which are then merged with carrageenan, a naturally occurring polysaccharide sourced from red seaweed Furcellaria Lumbricalis. The resultant bio composite displays encouraging mechanical traits, rendering it suitable for a variety of agricultural applications. The employment of wheat straw not only offers an environmentally conscious substitute but also addresses the predicament of disposing of agricultural waste. Regarding its application, the biodegradable composite can serve as a material for seedling trays. Due to the composite natural propensity to break down over time, long-term environmental pollution is prevented. Additionally, the material biodegradability is improved by its contact with soil microbes, enhancing the overall sustainability of agricultural methods. The outcomes of this study underscore the potential of the biodegradable wheat straw and carrageenan composite as a sustainable substitute for diverse agricultural applications. The development and assimilation of such environmentally friendly materials contribute to the ongoing endeavours to promote sustainable practices in agriculture, addressing both ecological apprehensions and the necessity for pioneering solutions in the field.
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Beletskaia, Ekaterina Iakovlevna, Svetlana Petrovna Chibis, Liudmila Anatolevna Krotova, and Vladimir Aleksandrovich Shelontsev. "The study of chemical compounds influence on morphological and population traits of soft wheat." In All-Russian scientific conference. Publishing house Sreda, 2019. http://dx.doi.org/10.31483/r-32850.
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The paper deals with the use of chemical compounds in soft wheat breeding, the role of induced mutations in plant improvement. The paper presents the effects of fungicides influence on morpho-logical and population traits of soft wheat. Laboratory experiments revealed the effects of disinfect-ants, the concentrations of their active components and the period from treatment to the formation sprouts of soft spring wheat Pavlogradka. The effect of systemic fungicides Comfort, AltSil, Ter-rasil and Alcasar was studied whet applied at recommended dose and greater than twice the normal values. They were compared with control samples without treatment. The sowing qualities of treated seeds were unstable, morphological and population traits of wheat seedlings were not homogeneous.
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Cui, Fu-Xing, Jin-Feng Song, Dao-Guang Zhu, et al. "Effects of Oxalic Acid on Physiological-biochemical Traits of Cold Temperate Larix gmelinii Seedlings under Soil Nutrient Deficiency." In The International Conference on Biological Sciences and Technology. Atlantis Press, 2016. http://dx.doi.org/10.2991/bst-16.2016.49.
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A. Ali. AL-TAHER, Zainab. "EFFECT OF NITROGEN FERTILIZER AND ASCORBIC ACID ON SOME CHEMICAL AND ANATOMICAL CHARACTERISTICS LEAVES OF PLANT PAULOWNIA TOMENTOSA." In VIII.International ScientificCongressofPure,AppliedandTechnological Sciences. Rimar Academy, 2023. http://dx.doi.org/10.47832/minarcongress8-13.
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This study was carried out at the Agricultural Research Station of the University of Basra's College of Agriculture in a canopy covered with saran cloth on paulownia tree seedlings. All experimental plants were fertilized with compound fertilizer (20-20-20) NPK monthly throughout the study period at a rate of 1 g per pot as a constant factor. Two factors were examined in the study: the first is nitrogen fertilization with urea fertilizer (46% nitrogen) using three levels (0, 1.6, 3.2 g plant-1), and the second factor is spraying with three concentrations of ascorbic acid (0, 30, 60 mg l-1). The anatomical characteristics of paulownia leaves were studied after six months of treatment, as the anatomical sections were prepared using paraffin technology. According to the study's findings, the comparison treatment of nitrogen fertilizer compared to the other concentrations, was noticeably superior and the highest value for the thickness of the cuticle layer was 17.33 micrometers, while the treatment recorded 2.3 g. Plant-1 had the lowest value of 10.33 micrometers. The comparison treatment of nitrogen fertilizer gave the lowest values for leaves content of total chlorophyll and carbohydrates, thickness of the epidermis layer, length of columnar cells, a diameter of spongy cells, and diameter of small and large vascular bundles (83, 86.80, 8.72, 166.67, 90, 146.67, 686.67), respectively, while the treatment recorded 2.3 g Plant-1 has the highest rates for the same traits. The treatment with ascorbic acid 60 mg l-1 compared to the other concentrations, was noticeably superior were recorded for the chemical and anatomical characteristics, except for the thickness of the cuticle layer. As for the interaction between nitrogen fertilizer and ascorbic acid, the treatment of the interaction between nitrogen fertilizer 3.2 g plant-1, ascorbic acid 60 mg l-1 recorded the highest rate for all chemical and anatomical characteristics and significantly different from the other interactions, which has a good impact on the paulownia plant's growth properties.
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Korlateanu, L., Lolita Melian, Victoria Mihăilă, Alina Ganea, and M. Pitiul. "Study of the storage potential of tomato (Solanum lycopersicum l.) collection samples under Ex situ conservation." In Scientific International Symposium “Advanced Biotechnologies - Achievements and Prospects” (VIth Edition). Institute of Genetics, Physiology and Plant Protection, 2022. http://dx.doi.org/10.53040/abap6.2022.93.
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In long-term ex situ conservation of plant germplasm in genetic banks, the main task is to pre-serve the viability of the seeds, since as a result of aging the seeds gradually lose their germination capacity and genetic homogeneity [6]. Therefore, the study of the storage potential (SP) of seeds is a very important step for ex situ conservation of plant genetic resources, especially during long-term storage of collection accessions in a plant genetic bank. In recent years, the determination of this potential has been practiced in many plant genetic banks in different countries [2, 4]. In order to study the storage potential, which indicates the longevity of collection samples during storage, the method of accelerated aging (AA) of seeds is of great interest, the essence of which consists in the artificial acceleration of aging by exposing seeds for a short time at elevated temperature and high relative humidity [1]. There are a number of studies that compared the physiological and biochemical changes in seeds during accelerated aging and long-term storage. Accelerated seed aging allows evaluating the differences between varieties of different types of crops. With the help of the test, it is possible to monitor gene pool samples, i.e. to conduct a permanent record of seed viability and classify genotypes from working and active collections according to the parameters of AA. The test allows to: 1. Identify samples that are not suitable for long-term storage. 2. Give recommendations on the timing of seed reproduction. 3. Indicate the need to restore the viability of valuable collection samples. The aim of the research was to study the storage potential of to-mato collection samples according to various morphophysiological and biochemical parameters of seeds and seedlings after applying tests for accelerated aging of seeds and electrolyte leakage and to gradate genotypes for this complex trait before ex situ conservation.
Reports on the topic "Seedling traits"
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Sela, Hanan, Eduard Akhunov, and Brian J. Steffenson. Population genomics, linkage disequilibrium and association mapping of stripe rust resistance genes in wild emmer wheat, Triticum turgidum ssp. dicoccoides. United States Department of Agriculture, 2014. http://dx.doi.org/10.32747/2014.7598170.bard.
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The primary goals of this project were: (1) development of a genetically characterized association panel of wild emmer for high resolution analysis of the genetic basis of complex traits; (2) characterization and mapping of genes and QTL for seedling and adult plant resistance to stripe rust in wild emmer populations; (3) characterization of LD patterns along wild emmer chromosomes; (4) elucidation of the multi-locus genetic structure of wild emmer populations and its correlation with geo-climatic variables at the collection sites. Introduction In recent years, Stripe (yellow) rust (Yr) caused by Pucciniastriiformis f. sp. tritici(PST) has become a major threat to wheat crops in many parts of the world. New races have overcome most of the known resistances. It is essential, therefore, that the search for new genes will continue, followed by their mapping by molecular markers and introgression into the elite varieties by marker-assisted selection (MAS). The reservoir of genes for disease and pest resistance in wild emmer wheat (Triticumdicoccoides) is an important resource that must be made available to wheat breeders. The majority of resistance genes that were introgressed so far in cultivated wheat are resistance (R) genes. These genes, though confering near-immunity from the seedling stage, are often overcome by the pathogen in a short period after being deployed over vast production areas. On the other hand, adult-plant resistance (APR) is usually more durable since it is, in many cases, polygenic and confers partial resistance that may put less selective pressure on the pathogen. In this project, we have screened a collection of 480 wild emmer accessions originating from Israel for APR and seedling resistance to PST. Seedling resistance was tested against one Israeli and 3 North American PST isolates. APR was tested on accessions that did not have seedling resistance. The APR screen was conducted in two fields in Israel and in one field in the USA over 3 years for a total of 11 replicates. We have found about 20 accessions that have moderate stripe rust APR with infection type (IT<5), and about 20 additional accessions that have novel seedling resistance (IT<3). We have genotyped the collection using genotyping by sequencing (GBS) and the 90K SNP chip array. GBS yielded a total 341K SNP that were filtered to 150K informative SNP. The 90K assay resulted in 11K informative SNP. We have conducted a genome-wide association scan (GWAS) and found one significant locus on 6BL ( -log p >5). Two novel loci were found for seedling resistance. Further investigation of the 6BL locus and the effect of Yr36 showed that the 6BL locus and the Yr36 have additive effect and that the presence of favorable alleles of both loci results in reduction of 2 grades in the IT score. To identify alleles conferring adaption to extreme climatic conditions, we have associated the patterns of genomic variation in wild emmer with historic climate data from the accessions’ collection sites. The analysis of population stratification revealed four genetically distinct groups of wild emmer accessions coinciding with their geographic distribution. Partitioning of genomic variance showed that geographic location and climate together explain 43% of SNPs among emmer accessions with 19% of SNPs affected by climatic factors. The top three bioclimatic factors driving SNP distribution were temperature seasonality, precipitation seasonality, and isothermality. Association mapping approaches revealed 57 SNPs associated with these bio-climatic variables. Out of 21 unique genomic regions controlling heading date variation, 10 (~50%) overlapped with SNPs showing significant association with at least one of the three bioclimatic variables. This result suggests that a substantial part of the genomic variation associated with local adaptation in wild emmer is driven by selection acting on loci regulating flowering. Conclusions: Wild emmer can serve as a good source for novel APR and seedling R genes for stripe rust resistance. APR for stripe rust is a complex trait conferred by several loci that may have an additive effect. GWAS is feasible in the wild emmer population, however, its detection power is limited. A panel of wild emmer tagged with more than 150K SNP is available for further GWAS of important traits. The insights gained by the bioclimatic-gentic associations should be taken into consideration when planning conservation strategies.
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Moore, Gloria A., Gozal Ben-Hayyim, Charles L. Guy, and Doron Holland. Mapping Quantitative Trait Loci in the Woody Perennial Plant Genus Citrus. United States Department of Agriculture, 1995. http://dx.doi.org/10.32747/1995.7570565.bard.
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As is true for all crops, production of Citrus fruit is limited by traits whose characteristics are the products of many genes (i.e. cold hardiness). In order to modify these traits by marker aided selection or molecular genetic techniques, it is first necessary to map the relevant genes. Mapping of quantitative trait loci (QTLs) in perennial plants has been extremely difficult, requiring large numbers of mature plants. Production of suitable mapping populations has been inhibited by aspects of reproductive biology (e.g. incompatibility, apomixis) and delayed by juvenility. New approaches promise to overcome some of these obstacles. The overall objective of this project was to determine whether QTLs for environmental stress tolerance could be effectively mapped in the perennial crop Citrus, using an extensive linkage map consisting of various types of molecular markers. Specific objectives were to: 1) Produce a highly saturated genetic linkage map of Citrus by continuing to place molecular markers of several types on the map. 2) Exploiting recently developed technology and already characterized parental types, determine whether QTLs governing cold acclimation can be mapped using very young seedling populations. 3) Determine whether the same strategy can be transferred to a different situation by mapping QTLs influencing Na+ and C1- exclusion (likely components of salinity tolerance) in the already characterized cross and in new alternative crosses. 4) Construct a YAC library of the citrus genome for future mapping and cloning.
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Veilleux, Richard, and David Levy. Potato Germplasm Development for Warm Climates. United States Department of Agriculture, 1992. http://dx.doi.org/10.32747/1992.7561057.bard.
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Complex potato hybrids derived from crosses between cv. Atlantic and 11 clones of three genomic compositions, all with an unadapted component from previously identified heat tolerant accessions, were evaluated in the field in Israel and Virginia and in controlled environments in Israel. Heat tolerance was exhibited in the field by the ability of many of these hybrids to tuberize under severe heat stress when cv. Atlantic did not tuberize at all. The complex hybrids also exhibited fewer internal defects (heat necrosis, hollow heart) than Atlantic. Studies to determine if heat stress applied during anther culture or to pollen samples prior to pollination could affect gametic selection towards more heat tolerant progenies were also undertaken. There was some evidence of greater heat tolerance (longer survival under heat stress) in the anther-derived population that had been regenerated under heat stress. The seedlings resulting from crosses with heat-treated pollen also exhibited greater haulm growth under heat stress compared with controls. However, the poor adaption of the germplasm prevented a firm conclusion about gametic selection. The introduction of exotic germplasm into cultivated potato has considerable potential to adapt potato to nontraditional growing seasons and climates. However, such hybrids will require continued selection and evaluation to retain the traits required for commercial production.
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Guy, Charles, Gozal Ben-Hayyim, Gloria Moore, Doron Holland, and Yuval Eshdat. Common Mechanisms of Response to the Stresses of High Salinity and Low Temperature and Genetic Mapping of Stress Tolerance Loci in Citrus. United States Department of Agriculture, 1995. http://dx.doi.org/10.32747/1995.7613013.bard.
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The objectives that were outlined in our original proposal have largely been achieved or will be so by the end of the project in February 1995 with one exception; that of mapping cold tolerance loci based on the segregation of tolerance in the BC1 progeny population. Briefly, our goals were to 1) construct a densely populated linkage map of the citrus genome: 2) map loci important in cold and/or salt stress tolerance; and 3) characterize the expression of genes responsive to cold land salt stress. As can be seen by the preceding listing of accomplishments, our original objectives A and B have been realized, objective C has been partially tested, objective D has been completed, and work on objectives E and F will be completed by the end of 1995. Although we have yet to map any loci that contribute to an ability of citrus to maintain growth when irrigated with saline water, our very encouraging results from the 1993 experiment provides us with considerable hope that 1994's much more comprehensive and better controlled experiment will yield the desired results once the data has been fully analyzed. Part of our optimism derives from the findings that loci for growth are closely linked with loci associated with foliar Cl- and Na+ accumulation patterns under non-salinization conditions. In the 1994 experiment, if ion exclusion or sequestration traits are segregating in the population, the experimental design will permit their resolution. Our fortunes with respect to cold tolerance is another situation. In three attempts to quantitatively characterize cold tolerance as an LT50, the results have been too variable and the incremental differences between sensitive and tolerant too small to use for mapping. To adequately determine the LT50 requires many plants, many more than we have been able to generate in the time and space available by making cuttings from small greenhouse-grown stock plants. As it has turned out, with citrus, to prepare enough plants needed to be successful in this objective would have required extensive facilities for both growing and testing hardiness which simply were not available at University of Florida. The large populations necessary to overcome the variability we encountered was unanticipated and unforeseeable at the project's outset. In spite of the setbacks, this project, when it is finally complete will be exceedingly successful. Listing of Accomplishments During the funded interval we have accomplished the following objectives: Developed a reasonably high density linkage map for citrus - mapped the loci for two cold responsive genes that were cloned from Poncirus - mapped the loci for csa, the salt responsive gene for glutathione peroxidase, and ccr a circadian rhythm gene from citrus - identified loci that confer parental derived specific DNA methylation patterns in the Citrus X Poncirus cross - mapped 5 loci that determine shoot vigor - mapped 2 loci that influence leaf Na+ accumulation patterns under non-saline conditions in the BC1 population - mapped 3 loci that influence leaf Na+ accumulation paterns during salt sress - mapped 2 loci that control leaf Cl- accumulation patterns under non-saline conditions - mapped a locus that controls leaf Cl- accumulation patterns during salt stress Screened the BC1 population for growth reduction during salinization (controls and salinized), and cold tolerance - determined population variation for shoot/root ratio of Na+ and Cl- - determined levels for 12 inorganic nutrient elements in an effort to examine the influence of salinization on ion content with emphasis on foliar responses - collected data on ion distribution to reveal patterns of exclusion/sequestration/ accumulation - analyzed relationships between ion content and growth Characterization of gene expression in response to salt or cold stress - cloned the gene for the salt responsive protein csa, identified it as glutathione peroxidase, determined the potential target substrate from enzymatic studies - cloned two other genes responsive to salt stress, one for the citrus homologue of a Lea5, and the other for an "oleosin" like gene - cold regulated (cor) genes belonging to five hybridization classes were isolated from Poncirus, two belonged to the group 2 Lea superfamily of stress proteins, the others show no significant homology to other known sequences - the expression of csa during cold acclimation was examined, and the expression of some of the cor genes were examined in response to salt stress - the influence of salinization on cold tolerance has been examined with seedling populations - conducted protein blot studies for expression of cold stress proteins during salt stress and vice versa
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Livensperger, Carolyn, Rebecca Weissinger, Luke Gommermann, and Alice Wondrak Biel. Riparian monitoring of wadeable streams on the Fremont River, Capitol Reef National Park, 2009?2021. National Park Service, 2023. http://dx.doi.org/10.36967/2301391.
Full textAbstract:
The goal of Northern Colorado Plateau Network (NCPN) riparian monitoring is to deter-mine long-term trends in hydrologic, geomorphic, and vegetative properties of wadeable streams in the context of changes in other ecological drivers, stressors, and processes. This information is intended to provide early warning of resource degradation and determine natural variability of wadeable streams. This report summarizes NCPN monitoring of the Fremont River in Capitol Reef National Park (NP) from water years 2009 to 2021. The focus of this report is to (1) examine patterns in water availability at one monitoring reach from 2010 to 2021, and (2) present geomorphology and vegetation data from four reaches monitored from 2009 to 2021. Vegetation sampling and geomorphology surveys were completed at varying intervals throughout the time period; this report looks at changes within single reaches and establishes a baseline for future comparisons. There are four monitoring reaches established on the Fremont River: (1) F-01, approximately 2.5 kilometers upstream of a knickpoint (sharp change in channel slope) and associated waterfall that emerged following construction of State Highway 24 in 1964, (2) F-07, in a large oxbow that was cut off due to the highway construction, (3) F-04, approximately 1.5 kilometers downstream of the knickpoint, and (4) F-14, approximately 4.8 kilometers downstream of the knickpoint. Geomorphic and vegetation surveys took place at all reaches. Hydrologic monitoring occurred only at F-01. From 2001 to 2021, the entire range of flows recorded at a gaging station on the Fremont River upstream of the park near Bicknell, Utah, decreased, with the steepest decreases occurring in the highest flow percentiles. Continuous hydrologic monitoring at reach F-01 in the park from 2010 to 2021 showed perennial flows in the Fremont River, with lower flows during the irrigation season (April 1?October 31). The irrigation season was also characterized by greater evapotranspiration, which may be exacerbated in the future due to higher air temperatures. Lower observed inputs and greater evapotranspiration suggest the Fremont River is at risk for progressively lower flows over time. While overbank flows occurred infrequently in the monitoring reach, inhibiting cottonwood recruitment, groundwater levels remained shallow enough to support mature cottonwood trees. Protecting spring snowmelt flows of 94 cfs (the average annual maximum 14-day rolling mean at reach F-01), or greater should maintain the current wetland vegetated zone. Maintaining the hydrologic record was challenging due to high-magnitude flood events and turbid flows; the park should consider a gaging station for an accurate discharge record. Geomorphic surveys showed net sediment deposition at reaches F-01 and F-14 in the channels, banks, and floodplains from 2009 to 2021, with more deposition occurring earlier in the study period. A large flood event in 2013 resulted in high flows and deposition of close to one meter at F-01. Only localized erosion occurred, and thalweg surveys showed that stream channels were either stable or increasing in elevation. Reach F-07, the abandoned oxbow, exhibited little geomorphic change over the study period. Riparian vegetation was characteristic of a Fremont cottonwood woodland, with canopy closure up to 30% and a mixed understory of shrubs and herbaceous species. Obligate wetland vegetation cover of 5%?10% was present at reaches F-01, F-04, and F-14. Reach F-07, in the oxbow, has transitioned to an upland system, with little to no canopy cover and no obligate wetland species. While mature cottonwoods were present in reaches F-01, F-04, and F-14, there was limited evidence of seedlings or saplings graduating into larger size classes. Cottonwood seedlings are primarily resprouts from beaver-browsed trees, although one seedling recruitment event was observed in 2014, following high flows in late 2013. Protecting some cottonwoods with chicken wire may help protect the larger size classes and maintain a mixed-age woodland. Exotic plant species cover was less than 10% in reaches F-01, F-04, and F-14. Efforts to control Russian olive (Eleagnus angustifolia) along the Fremont River appear to have been successful in these reaches. In reach F-07, exotic plant cover ranged from 9% to 25%, with notable spikes in Russian thistle (Salsola tragus) and cheatgrass (Bromus tectorum) in 2010 and 2011, respectively.
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Perkins, Dustin. Invasive exotic plant monitoring at Colorado National Monument: 2019 field season. Edited by Alice Wondrak Biel. National Park Service, 2021. http://dx.doi.org/10.36967/nrr-2286650.
Full textAbstract:
Invasive exotic plant (IEP) species are a significant threat to natural ecosystem integrity and biodiversity, and controlling them is a high priority for the National Park Service. The North-ern Colorado Plateau Network (NCPN) selected the early detection of IEPs as one of 11 monitoring protocols to be implemented as part of its long-term monitoring program. This report represents work completed at Colorado National Monument during 2019. During monitoring conducted June 12–19, a total of 20 IEP species were detected on monitoring routes and transects. Of these, 12 were priority species that accounted for 791 separate IEP patches. IEPs were most prevalent along riparian areas. Yellow sweetclover (Melilotis officinale) and yellow salsify (Tragopogon dubius) were the most commonly detected priority IEPs along monitoring routes, representing 73% of all priority patches. Patches of less than 40 m2 were typical of nearly all priority IEP species except yellow sweetclover. A patch management index (PMI) was created by combining patch size class and percent cover for each patch. In 2019, a large majority of priority IEP patches were assigned a PMI score of low (46%) or very low (50%), indicating small and/or sparse patches where control is generally still feasible. This is similar to the numbers for 2017, when 99% of patches scored low or very low in PMI. Seventy-eight percent of tree patches were classified as seedlings or saplings, which require less effort to control than mature trees. Cheatgrass (Anisantha tectorum) was the most common IEP recorded in transects, found in 30–77% of transects across the different routes. It was the only species found in transects on all monitoring routes. When treated and untreated extra areas near the West Entrance were compared, the treated area had comparable or higher lev-els of IEPs than the untreated area. When segments of monitoring routes conducted between 2003 and 2019 were compared, results were mixed, due to the different species monitored in different time periods. But in general, the number of IEPs per 100 meters is increasing or remaining constant over time. There were notable increases in IEP patches per 100 meters on several routes in 2019: field bindweed (Convolvulus arvensis) along East Glade Park Road; Siberian elm (Ulmus pumila) in Red Canyon; yellow salsify along East Glade Park Road, No Thoroughfare Canyon, No Thoroughfare Trail, and Red Canyon; and yellow sweetclover in No Thoroughfare Canyon and Red Canyon. Network staff will return to re-sample monitoring routes in 2021.