Dissertations / Theses: 'Seedling physiology'

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Logsdon, Charles A. "Mutants of Arabidopsis thaliana exhibiting abnormal gravitropism and seedling plastid development." [Bloomington, Ind.] : Indiana University, 2005. http://wwwlib.umi.com/dissertations/fullcit/3162266.

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Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2005. Title from PDF t.p. (viewed Dec. 2, 2008). Source: Dissertation Abstracts International, Volume: 66-01, Section: B, page: 0146. Chair: Roger P. Hangarter.

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Mahwood, T. "Physiology of metal ion-induced effects on germination and seedling growth in cereals." Thesis, University of Edinburgh, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.657209.

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The effects of zinc, lead and copper ions, at concentrations up to 10 mM, on germination and seedling vigour of wheat, barley and rice were investigated. Percentage germination was unaffected by lead and zinc ions in the three species tested. The highest concentration of copper ions (10 mM) decreased the percentage germination in rice. Rice seedlings were grown in controlled environment cabinets using a nutrient culture technique. A copper ion concentration of 8 μM in the culture solution was found to inhibit the elongation of the longest root. Seedlings were grown in nutrient solutions at pH 5.5, 5.0 and 4.5, and three concentrations of copper ions. The reduction in all the growth parameters was highest at pH 4.5 in all copper ion treatments. The amount of chlorophyll in the uppermost fully-expanded leaves of the seedlings grown at pH 4.5, was considerably less than that in comparable leaves of the control seedlings. The effect of copper ions on root plasma membranes of the seedlings was estimated by measuring K+ leakage from intact roots. A larger amount of K+ leaked from roots when seedlings were incubated with high (16 μM) copper ion concentrations than when seedling roots were incubated in water. Similarly, the effect of copper ions on root lipid peroxidation as measured by TBA-rm(2-thiobarbituric acid-reactive material) accumulation, showed that more TBA-rm was accumulated in copper ion treated roots than in control roots. The effect of various copper ion concentrations on the morphology and ultrastructure of the roots was studied using light and scanning electron microscopy. The results showed that copper ions caused a reduction in the length of the root hair zone and of root hair length, a reduction in the size of the root cells, and initiation of lateral root closer to the root tip, compared to seedlings grown in control solutions.

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Mahmood, Tariq. "Physiology of metal ion-induced effects of germination and seedling growth in cereals." Thesis, University of Edinburgh, 1995. http://hdl.handle.net/1842/12550.

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Bigley, Richard Ernest. "Ecological physiology of conifer seedling and sapling suppression by, and release from, competing vegetation." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28625.

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The overall objective of this thesis was to improve our understanding of the light environment associated with two of the major deciduous competitors of commercial conifer seedlings in low elevation coastal British Columbia, and the physiological response of young conifers to specific environments and changes in the environment. Studies were conducted to investigate: 1) seasonal and herbicide-induced changes in the light regimes beneath the canopies of two brush species, 2) growth and physiology of seedlings of three conifer species in several different deciduous brush environments throughout the year, and 3) changes in the physiology and growth of suppressed conifer saplings when different methods and schedules were used to reduce shading from an overtopping red alder canopy. Seasonal changes in the light quantity and quality were documented within salmonberry (Rubus spectabilis Pursch) and below red alder (Alnus rubra Bong.) canopies. The prediction of light attenuation within salmonberry canopies using the Beer-Lambert law was good for foliated canopies using leaf area index, and defoliated canopies using stem area index. As salmonberry leaf area increased, the ratio of red to far-red light declined exponentially. Growth of grand fir (Abies qrandis (Dougl.) Forbes), western hemlock (Tsuga heterophylla (Raf.) Sarg.) and Douglas-fir (Pseudetsuga menziesii (Mirbel) Franco) seedlings decreased with increases in the canopy density of overtopping deciduous species. Physiological differences between conifer species and differences between overtopping canopy treatments declined in the autumn and winter. Based on the physiological measurements, suppression of the shade intolerant Douglas-fir seedlings was greatly reduced during the period that overtopping deciduous canopies were leafless. Animal damage reduces growth and probably increases the duration seedlings are under overtopping canopies. Suppressed Douglas-fir saplings released from overtopping by red alder canopies showed the greatest growth response when the alder canopies were removed in the spring; complete removal of the alder canopy during the summer had a predictably deleterious effect on the sapling physiology and growth. Herbicide injections resulted in a slower but predictable increase in conifer growth. Forestry, Faculty of Graduate

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Sekharan, Soja. "Aged soybean (Glycine max [L.] Merrill) seeds – their physiology and vigor assessment." The Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1135809134.

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MacAllister, Sarah Louise. "Regeneration of Scots pine (Pinus sylvestris L.) under drought." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/19560.

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Drought-induced tree mortality is a phenomenon affecting many forest ecosystems and is predicted to increase under ongoing climate change. Forest stability partly depends on regeneration: the process of renewing mature forest with subsequent generations. As seedlings are more susceptible to drought effects than mature trees, mortality of the seedling bank can represent a major bottleneck controlling forest structure and species composition. Scots Pine (Pinus sylvestris L.) is the most widely distributed of the Pinus species, covering a broad latitudinal gradient of ecological conditions. The thesis aims to deepen understanding of drought-induced mortality, while analysing intra-specific variation in the phenotypic and metabolic profile of Pinus sylvestris seedlings subjected to drought stress. I also consider the relevance of the results to the broader conceptual framework of drought-induced mortality. The experiments utilise seeds from different populations of origin (provenances) across the north-south axis of the European range of Pinus sylvestris, in order to determine the extent of regeneration capacity in this species under drought. Seeds were collected from different populations (provenances) that, along with other climatic and edaphic differences, span a gradient of water availability: from wet (Scotland) to intermediate (Austria, Poland) to dry (Spain). In Chapter 2, the effects of osmotic stress on the initial seedling establishment stage were studied by comparing phenotypic responses across provenances. Seedling germination, early growth, osmotic stress tolerance and survival were investigated using a polyethylene glycol irrigation treatment as a proxy for rapid and severe drought. Treatment, provenance and interaction effects were found for rate of germination, final proportion of seeds germinated, seedling size, and superoxide dismutase activity (an antioxidant enzyme). Root investment was affected by both provenance and time to germination. Although there was no significant effect of provenance on survival, a trend towards increased probability of survival under osmotic stress was indicated for the southernmost (driest) as compared with the northernmost (wettest) provenance. Chapter 3 investigates the responses of older seedlings (at 10 months) to a drying down of soil moisture for 40 days. Morphological and physiological data were collected to assess intra-specific and intra-population variation in the seedling stress response under drought. A metabolomics analysis using Ultra performance Liquid chromatography followed by mass spectrometry (UPLC/MS) was carried out to investigate whether metabolic markers could be identified that are suggestive of heightened oxidative stress and whether populations in different climatic and edaphic environments show variation in metabolic activity under drought. Preliminary results suggest large intra-population variability yet clear differentiation in metabolic responses to drought over the time course of the experiment. Univariate and multivariate analyses indicated that among the most significant increases in response to drought were those involved in osmoprotective and antioxidant capabilities, including the free amino acid proline and a quercetin derivative (a flavonoid). Interestingly, provenances, either under experimental drought or not, did not show significantly different metabolite profiles, even though provenance and its interaction with drought treatment did significantly affect seedling biomass and photochemical efficiency. In Chapter 4 the effects of provenance, maternal parentage and seed weight on germination rate, final germination percentage, as well as seedling drought responses in biomass allocation and the expression of selected antioxidant genes were analysed. Seed weights were measured individually and seed weight was found to have a strong positive effect on: germination rate, seedling dry weights, and number of needles. Expression of two antioxidant enzymes increased under drought. Seed weight was strongly determined by provenance and maternal parentage as well as their interaction. However, root to shoot biomass allocation depended on provenance and maternal effects that were not mediated by seed weight effects. Principal component analysis indicated that the Spanish provenances could be characterised by a higher root to shoot ratio and stem weight. Specific leaf area was also found to be lowest for the Spanish provenances.

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Sparks, Aaron, Crystal Kolden, Alan Talhelm, et al. "Spectral Indices Accurately Quantify Changes in Seedling Physiology Following Fire: Towards Mechanistic Assessments of Post-Fire Carbon Cycling." MDPI AG, 2016. http://hdl.handle.net/10150/621493.

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Fire activity, in terms of intensity, frequency, and total area burned, is expected to increase with a changing climate. A challenge for landscape-level assessment of fire effects, often termed burn severity, is that current remote sensing assessments provide very little information regarding tree/vegetation physiological performance and recovery, limiting our understanding of fire effects on ecosystem services such as carbon storage/cycling. In this paper, we evaluated whether spectral indices common in vegetation stress and burn severity assessments could accurately quantify post-fire physiological performance (indicated by net photosynthesis and crown scorch) of two seedling species, Larix occidentalis and Pinus contorta. Seedlings were subjected to increasing fire radiative energy density (FRED) doses through a series of controlled laboratory surface fires. Mortality, physiology, and spectral reflectance were assessed for a month following the fires, and then again at one year post-fire. The differenced Normalized Difference Vegetation Index (dNDVI) spectral index outperformed other spectral indices used for vegetation stress and burn severity characterization in regard to leaf net photosynthesis quantification, indicating that landscape-level quantification of tree physiology may be possible. Additionally, the survival of the majority of seedlings in the low and moderate FRED doses indicates that fire-induced mortality is more complex than the currently accepted binary scenario, where trees survive with no impacts below a certain temperature and duration threshold, and mortality occurs above the threshold.

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MacKintosh, Hamish. "Developing the silviculture of continuous cover forestry : using the data and experience collected from the Glentress Trial Area." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7943.

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Continuous Cover Forestry (CCF) has become increasingly popular since the early 1990s. CCF utilises several silvicultural techniques in order to promote and enhance forest structural diversity and favours natural regeneration. As CCF is relatively new to the UK there are still areas of knowledge regarding management interventions that need to be improved upon. This study utilises simple models, seedling physiology and a hybrid gap model and applies them to the Glentress Trial Area which has been under transformation from even-aged forestry since 1952. These efforts have led to an improved understanding of thinning interventions and the effects they may have on future stand structure. Since the formation of the Forestry Commission in 1919, clearfell-replant forestry has been the main form of management practiced in the UK. CCF management differs in several respects and is commonly practiced using expert knowledge in Continental Europe. In the UK the knowledge-base is still growing and therefore simple models can prove useful for guiding management. This study investigated the use of the idealised reverse-J and the Equilibrium Growing Stock (EGS). This study found that the reverse-J shaped diameter distribution is maintained at the Trial, Block and sub- Block scale indicating that an irregular structure is being approached. In addition, the diminution coefficient, a parameter of the reverse-J distribution, falls within values typical of continental Europe. Comparison of the actual diameter-frequency distribution against an ideal reverse-J distribution can inform both thinning intensity and which diameter classes to target. The EGS, which is a volume–diameter distribution, examines standing volume and how that volume is distributed across three broad diameter classes. Typical distributions from the Swiss Jura indicate that percentage volume should be split 20:30:50 across diameter classes. The EGS analysis showed that standing volume in the Trial Area is much lower than European values at just 174 m3 ha-1. In addition, the classic 20:30:50 percent split was not observed. The 1990 data set showed a 49:43:8 distribution but by 2008 it was 40:41:19. As natural regeneration is favoured in CCF a better understanding of seedling physiology is essential. This study established open (15-35 m2 ha-1) and closed canopy plots (>35 m2 ha-1). Plot characteristics were recorded and then seedlings were selected for physical measurements, chlorophyll fluorescence and gas-exchange measurements. There were clear differences between the physical characteristics with a mean Apical Dominance Ratio (APR) of 1.41 for the open plots and 0.9 for the closed plots which is consistent with previous studies suggesting an APR of 1 is needed for successful regeneration. The chlorophyll fluorescence measurements showed a linear relationship with PAR. However, although the results of the gas-exchange measurements showed an increase in photosynthetic rates with PAR for open plots, there was no obvious relationship in the closed plots. As a result, the study did not find a linear relationship between photosynthetic rate and chlorophyll fluorescence. Finally a complex, hybrid gap model was used to investigate the effects of management on predicted future stand structure. The hybrid gap model, PICUS v1.41, was parameterised for Sitka spruce. The model was used to explore different management scenarios on stand structure over two time periods; 1954-2008 and 1952- 2075. The output from the group selection with underplanting scenario, which resembled the actual management, produced realistic output that was comparable to the stand characteristics measured during the 2008 assessment. The output from the 1952-2075 runs suggested that thinning to a residual basal area suitable to allow natural regeneration (<30 m2 ha-1) or a group selection with underplanting were the best management options for maintaining structural diversity.

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Roberts, Jessica Jaye Edna. "Incorporating low relative humidity and low temperatures into tree nursery growing regimes, effects on white spruce seedling growth, morphology and physiology." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ34408.pdf.

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Ertle, John Michael. "Effects of Short-term Chilling Stress on Seedling Quality and Post-transplanting Growth of Grafted and Nongrafted Watermelon." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1594742774066127.

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Hatzig, Sarah Vanessa [Verfasser]. "Breeding for climate change : genetics and physiology of seed vigor, seedling vigor and early drought resistance in winter oilseed rape (Brassica napus L.) / Sarah Vanessa Hatzig." Gießen : Universitätsbibliothek, 2015. http://d-nb.info/108012019X/34.

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Turchetto, Felipe. "POTENCIAL DO BANCO DE PLÂNTULAS COMO ESTRATÉGIA PARA RESTAURAÇÃO FLORESTAL NO EXTREMO SUL DO BIOMA MATA ATLÂNTICA." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/8766.

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Fundação de Amparo a Pesquisa no Estado do Rio Grande do Sul The seedling bank is crucial to the perpetuation of woody communities, represented in tropical regions by a large number of individuals, many of whom do not reach the upper strata. Thus, the present study aimed to evaluate the potential of seedling bank as a strategy to increase species richness in forest nurseries, aimed at ecological restoration of disturbed areas in southern Atlantic Forest biome. The work was divided into three chapters, which are organized according to the objectives: In Chapter I was analyzed the structure of a remaining stretch of seasonal Forest Subtropical and the potential of species to restore degraded areas were identified. Were installed 18 plots of 20 m x 10 m, where it was sampled the vegetation divided into four classes, according to their size: I - Bank of seedlings: 5 cm ≤ height (H) ≤ 55 cm; II - established natural regeneration: H > 55 cm and diameter at breast height (DAP) < 1 cm); III - Intermediate Stratum 1 cm ≤ DAP < 5 cm; and IV - arboreal stratum: DAP ≥ 5 cm. In Chapter II we study the resilience of a plant community after transplantation bank seedlings, conducted under different withdrawal intensities (0, 25, 50, 75 and 100% removal). In this study we used 18 plots (5 m x 5 m), which were subdivided into five subplots of 1 m x 2,5 m (totaling 90 subplots), in each subplot was randomized a removal of intensity. In Chapter III we study the survival and growth of seedlings in the nursery in different size classes. We collected data for survival and height increment, in a completely randomized design, considering five size classes (I - 05-15 cm; II 15,01-25 cm; III 25,01-35 cm; IV - 35,01-45 cm; V 45,01-55 cm), evaluated every two months for a period of ten months. Also considered physiological parameters for the most abundant species, considering two environments (understory and nursery), designed to evaluate the adaptation of transplanted seedlings. Thus, it was found that the Bank of seedlings is a useful tool to increase the number of species produced in nurseries, given that the majority of transplanted species showed good development and the plots where different intensities were applied transplantation has been able to recover the richness and abundance of species present at baseline. Considering forest structure, dynamics of natural regeneration after transplantation and the development of seedlings in the nursery, there is for the region as a species Actinostemon concolor, Nectandra megapotamica, Apuleia leiocarpa, Trichilia elegans, Maytenus aquifolia, Trichilia claussenii and Eugenia rostrifolia. O banco de plântulas é fundamental para a perpetuação das comunidades arbustivo-arbóreas, sendo representado em regiões tropicais por um elevado número de indivíduos, dos quais muitos não conseguem atingir os estratos superiores. Assim, a presente pesquisa teve como objetivo avaliar o potencial do banco de plântulas como estratégia para aumentar a riqueza de espécies em viveiros florestais, visando à restauração ecológica de áreas alteradas no extremo sul do Bioma Mata Atlântica. O trabalho foi estruturado em três capítulos, os quais estão organizados de acordo com os objetivos: No Capítulo I foi analisado a estrutura de um trecho de remanescente de Floresta Estacional Subtropical, bem como foi identificado o potencial de espécies para restauração de áreas alteradas. Foram instaladas 18 parcelas de 20 m x 10 m, onde foi amostrada a vegetação dividida em quatro classes, conforme o seu tamanho: I - Banco de plântulas: 5 cm ≤ altura (H) ≤ 55 cm; II - Regeneração natural estabelecida: H > 55 cm e diâmetro a altura do peito (DAP) < 1 cm); III Estrato intermediário: 1 cm ≤ DAP < 5 cm; e IV Estrato arbóreo: DAP ≥ 5 cm. No Capítulo II foi avaliado a resiliência de uma comunidade vegetal após o transplante do banco de plântulas, conduzido sob diferentes intensidades de retirada (0, 25, 50, 75 e 100% de retirada). Nesse estudo foram utilizadas 18 parcelas (5 m x 5 m), as quais foram subdivididas em cinco subparcelas de 1 m x 2,5 m (totalizando 90 subparcelas), em cada subparcela foi casualizado uma intensidade de retirada. No Capítulo III foi avaliado a sobrevivência e o crescimento das mudas no viveiro em diferentes classes de tamanho. Foram coletados dados de sobrevivência e incremento em altura, em delineamento inteiramente casualizado, considerando cinco classes de tamanho (I 05-15 cm; II 15,01-25 cm; III 25,01-35 cm; IV 35,01-45 cm; V 45,01-55 cm), avaliadas a cada dois meses, por um período de dez meses. Também considerou-se parâmetros fisiológicos para as espécies mais abundantes, considerando dois ambientes (sub-bosque e viveiro), com intuito de avaliar a adaptação das mudas transplantadas. Desta forma, verificou-se que o banco de plântulas é uma ferramenta útil para aumentar o número de espécies produzidas em viveiros florestais, tendo em vista que a maioria das espécies transplantadas apresentaram bom desenvolvimento, bem como as parcelas onde foram aplicadas as diferentes intensidades de transplante tem conseguido recuperar a riqueza e abundância de espécies presentes inicialmente. Assim, considerando a estrutura da floresta, dinâmica da regeneração natural após o transplante e o desenvolvimento de mudas no viveiro, destaca-se para a região espécies como a Actinostemon concolor, Nectandra megapotamica, Apuleia leiocarpa, Trichilia elegans, Maytenus aquifolia, Trichilia claussenii e Eugenia rostrifolia.

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van, Gardingen Paul R. "Environmental and stomatal physiology of Nothofagus seedlings." Thesis, University of Canterbury. Botany, 1987. http://hdl.handle.net/10092/7573.

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The Maruia Valley on the West Coast of the South Island of New Zealand is a region with Nothofagus forest dominated by mixtures of N. fusca and N. menziesii. The Station Creek area was selected for environmental and gas exchange measurements with the two species. The mean daily temperature and vapour pressure deficit (VPD) variation was found to be up to two times higher on an open logged site than under both closed canopy and a small canopy gap. The light flux under closed canopy gap was 5% of that gap measured in the open. During summer the light flux under the canopy gap was up to 25% of that in the open. Gas exchange was measured using a LI-COR LI-6000 portable photosynthesis system. An improved set of formulae were developed for this system and have been implemented in a computer programme for the IBM PC and compatibles. Gas exchange measurements at Station Creek were used to determine the maximum rates of photosynthesis (Amax) and stomatal conductance (gmax) as well as the sensitivity of these estimates to VPD. The rates of gas exchange were higher in N. menziesii than N. fusea. No significant difference was found between species for the estimates of stomatal and photosynthetic sensitivity. In addition there was no difference between foliage growing in the open, under a canopy gap, or under closed canopy. Gas exchange measurements of saplings growing in a nursery at Rangiora on the east coast of the South Island gave similar results during early summer. As the season progressed, the rates were lower at Rangiora due to moderate water stress. It is suggested that Nothofagus seedlings have a wide ecological tolerance, which is in part due to the generalized stomatal response to VPD. This can explain how Nothofagus is capable of regenerating under a wide range of environmental conditions. Under extreme environments seedling growth is reduced and regeneration will succeed only in the absence of rapidly growing competing species.

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Al-Sobhi, Owdah Ayyad. "Greening and development in wheat seedlings." Thesis, Durham University, 1989. http://etheses.dur.ac.uk/6742/.

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The greening of etiolated first leaf blades of wheat (Triticium aestivum Mercia) seedlings (referred to in the text as leaf tissue) was studied in relation to tissue age and water stress. Use was made of whole seedlings, excised leaf blades and leaf blade segments. Responses to photoperiodic illumination were measured as changes in the levels of chlorophyll, total soluble protein and nucleic acids (both total and specific fractions). The pattern of greening in the whole seedlings, excised leaf blades and leaf blade segments was essentially the same in 6 and 10 day-old dark-grown tissues, where chlorophyll accumulation followed the age sequence along the leaf. Least chlorophyll accumulated in the tip of leaves of both ages but the older leaves contained less overall pigment than the younger leaves. Patterns of total soluble protein and total nucleic acid accumulation did not reflect the pattern shown by the chlorophyll. Protein accumulated most in the tip region, with nucleic acids being highest in the middle region. Water stress treatment reduced chlorophyll accumulation in leaf blade tissue, particularly in the intact seedlings. Protein levels, however, were more variable and appeared to reflect the ability of the younger tissue to accumulate this compound as a stress metabolite. Total nucleic acid levels were also elevated under water stress. Again, these effects were most marked on the intact seedlings, implying that an effect on the roots was also involved. The data from polyacrylamide gel electrophoresis of RNA fractions showed that the level of chloroplast RNA components was maintained up to 17 days for tissue incubated in the dark as well as in the light. Severe water stress treatments applied to the roots of whole seedlings resulted in the loss of ribosomal fraction in the leaves. However, this effect was not seen with mild water stress. Kinetin treatments during water stress did not appear to alter the pattern of cell component accumulation although in unstressed material, treatment with this compound enhanced chlorophyll accumulation slightly, especially in the young tissue. This indicates that, at the concentration used, the growth regulator was not able to alleviate the stress condition. The leaf blades of intact seedlings responded in a specific way which was much more pronounced than for excised leaf blades or leaf blade segments. It was concluded that some signalling was involved between the root and shoot tissues during water stress treatments.

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Kamaluddin, Mohammed. "The growth and physiology of tropical forest tree seedlings in relation to light." Thesis, University of Edinburgh, 1991. http://hdl.handle.net/1842/15134.

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This work reports the results of the experiment on the growth and physiology of tropical forest tree seedlings in relation to light. The experiments were carried out in a controlled environment simulating forest light conditions. The species studied were Anthocephalus chinensis (Lamk.) Rich. ex Walp., Bischofia javanica Blume, and Hopea odorata Roxb. from the moist forests of tropical Asia. The main aim of this study was to characterise the responses of seedlings in relation to (a) irradiance and nutrient supply, (b) shadelight quality, red to far-red (R:FR) ratio or low proportion of blue light, and (c) changing light availability. The species displayed differential growth responses when their seedlings were grown at different levels of irradiance and nutrient supply. Growth of gap species Bischofia was more plastic than that of the climax species Hopea. The growth of the former was substantially restricted when the nutrient supply was low at the higher irradiances. Pioneer species Anthocephalus responded to a low R:FR ratio by a large increase in stem extension growth with concomitant increase in allocation of dry matter to stem at the expense of leaf development. The effect of R:FR ratio on extension growth was independent of a low proportion of blue light. Very small amounts of blue light in the shadelight restricted leaf expansion in Anthocephalus and Bischofia, and increased specific stem length in the former. The climax species Hopea was relatively unresponsive to the R:FR ratios or the different proportions of blue light in the shadelight.

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Will, Rodney E. "The effects of rhizosphere inundation on the growth and physiology of red maple (Acer rubrum L.) seedlings derived from wet and dry sites." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-02132009-172358/.

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Cook, Paul Andrew. "Effect of the spruce root aphid, Pachypappa vesicalis on the growth and physiology of Sitka spruce seedlings." Thesis, Lancaster University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337573.

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Major, John E. "Ecophysiological assessment of western hemlock and western red cedar greenhouse stocktypes." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29534.

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Western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western red cedar (Thuja plicata Donn) seedlings from four dormancy induction treatment(s) (DIT) (i.e. long-day dry, long-day wet, short-day dry, and short-day wet) were planted on a high available soil moisture field site in British Columbia and monitored for physiological response and morphological development over the first growing season. Stomatal conductance (gwv) and net photosynthesis (Pn) were recorded over an environmental matrix of photosynthetically active radiation (PAR) (0 - 2.2 mmol m⁻² s⁻¹ ) and vapour pressure deficit (VPD) (0 - 2.5 or 4.0 kPa) on both first year grown and fully developed second year foliage. To compare stocktypes, physiological data were collected and analyzed in the following ways: (1) replicated data at stable environmental conditions once a month, (2) physiological response to one increasing environmental variable using boundary line analysis, and (3) physiological response surface to two simultaneously changing environmental variables. For western hemlock first year needles, short-day DIT had a higher gwv response to both increasing VPD and PAR. Both short-day and moisture stressed DIT improved Pn response to PAR, and the combination had the highest response. Short-day DIT seedlings initially were smaller, shorter, had a better seedling water balance ratio and lower shoot to root ratio. Short-day second year needles showed a slightly higher gwv response to both increasing VPD and PAR as compared to long-day seedlings; however, they showed no treatment differences for Pn versus PAR. All stocktypes had similar final morphological parameter values. For western red cedar first year foliage, moisture stressed DIT seedlings had greater Pn response to increasing PAR and VPD. Also, moisture stressed seedlings gwv response to increasing VPD and PAR was higher when compared to its' non moisture stressed daylength counterpart. The long-day wet seedlings initially had a larger root and shoot system as compared to the other stocktypes. Second year foliage exhibited no treatment differences for gwv and Pn response to PAR ' and VPD. All stocktypes had similar final morphological parameter values. Attempts to test stocktypes at stable environmental conditions proved, at times, difficult. Potentially large measurement variation due to atmospheric environmental changes, and not stocktype effect, could result. Boundary line analysis, when used correctly and with sufficient data, offers a good stocktype assessment method which enables the isolation of a physiological response to one environmental variable. Three dimensional surface response technique was required to provide a clear conceptual representation of two primary environmental variables' influence on seedling physiological response. Forestry, Faculty of Graduate

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Ercan, Oya. "Effect Of Drought And Salt Stresses On Antioxidant Defense System And Physiology Of Lentil (lens Culinaris M.) Seedlings." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609250/index.pdf.

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In this study, 14 days old lentil seedlings (Lens culinaris Medik cv. Sultan), which were subjected to 7 days of drought (20% PEG 6000), and salt (150 mM NaCl ) stress , were examined in a comparative manner for the effects of drought and salt stress treatments. In shoot and root tissues physiological parameters such as wet-dry weight, relative water content, root-shoot lengths, membrane electrolyte leakage, and lipid peroxidation in terms of malondialdehyde (MDA) were determined. H2O2 content, proline accumulation and chlorophyll fluorescence analysis were also performed. Changes in the activity of antioxidant enzymes such as superoxide dismutase (SOD: EC 1.15.1.1), catalase (CAT: EC 1.11.1.6) ascorbate peroxidase (APX: EC 1.11.1.11) and glutathione reductase (GR: EC 1.6.4.2) were observed upon stress treatments. In salt treated lentil seedlings, significant decreases in wet-dry weight, RWC, shoot-root length and chlorophyll fluorescence measurements indicated a sensitivity, when compared to drought treated plants. Higher MDA concentration and higher electrolyte leakage amounts are supported these results. APX, GR and proline seem to play important roles in antioxidant defense against salt stress for both tissues by removing reactive oxygen species and protecting macromolecules and membranes. GR and proline are also maintains the main protective mechanism against drought stress effects. SOD is active in drought stressed roots and salt stressed shoots, where the H2O2 contents are also observed to be increased.

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Tseng, Elizabeth Chang-Hsu. "The impact of ozone, water stress, and acid rain on the growth and physiology of fraser fir seedlings." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/77734.

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Three studies were conducted to determine the effects of ozone, water stress, and simulated acidic rain on the growth and physiology of Fraser fir seedlings. In Experiment I, seedlings were first exposed to 2 levels of moisture stress conditioning (MSC) for four weeks, and 3 levels of ozone ( < 0.02, 0.05, and 0.10 ppm) and three levels of water stress (control, moderate, and severe) for 10 wks. The 2 MSC levels were a control (well-watered at all times) and a stress treatment in which seedlings were not watered until pre-dawn needle water potential measurements ('I') fell below -1.0 MPa. The 3 levels of water stress were a control (well-watered at all times); a moderately stressed treatment (seedlings watered when 'I' levels fell between -0.8 and -1.0 MPa); and a severely stressed treatment (seedlings watered when 'I' fell below -1.2 MPa). Fraser fir seedlings were exposed to 3 levels of simulated rain (pH 3.0, 4.3, and 5.6) and 2 levels of ozone ( < 0.02 and 0.10 ppm) in Experiment II for 10 wks. Fraser fir seedlings in Experiment III were exposed to ozone levels of < 0.02, 0.05, and 0.10 ppm ozone and control, moderate, and severe water stress (as specified above) for 10 wks during the first year. Seedlings were then exposed to 2 levels of ozone ( < 0.02 and 0.10 ppm) for 10 wks in the following year. Analysis of data indicate that ozone of 0.10 ppm significantly decreased net photosynthesis (Pn) in one study but was not significant in reducing Pn in the other two studies. Ozone also failed to reduce growth significantly; however, decreasing trends were often apparent. Fraser fir biomass, transpiration (Ts), and needle conductance (Cs) were significantly decreased by water stress. Water-use efficiency was also improved as a result of prior moisture stress. Simulated acidic rain did not result in any significant changes in biomass accumulation, height, or diameter increment over the ten week period of the study. A solution of pH 3.0 did result in significantly higher root surface area and significantly reduced Ts after 5 wks of exposure; these responses are possibly due to a fertilization effect. No treatment interactions were significant. However, the combined, cumulative effect of all of these stresses may contribute to an overall decline in forest ecosystem productivity. Master of Science

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21

Jassim, Raad Ahmed. "Effect of haloxyfop and fluazifop on morphology and fatty acid synthesis of annual blue grass (Poa annua L.) seedlings." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186541.

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Haloxyfop-methyl, methyl-2-[4-[[3-chloro-5-(triflouromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid] and fluazifop-butyl, (+)-butyl-2-[4-[[5-(trifluoromethyl)-2-pyridinyl] oxy]phenoxy]propanoic acid are used for selective control of annual and perennial gramineous weeds in broadleaf crops. Annual blue grass (Poa annua L.) is controlled by haloxyfop-methyl but not by fluazifop-butyl. Research was conducted to determine the effect of each herbicide on growth, morphology, lipid synthesis and acetyl-CoA carboxylase activity, of this species, and to determine physiological mechanism of annual blue grass tolerance to fluazifop-butyl. Techniques used in this research were growth measurements, light and electron microscopy, TLC, and enzyme assay for acetyl-CoA carboxylase. Haloxyfop-methyl at 15 μM when applied preemergence caused 96% reduction of root growth of annual blue grass whereas fluazifop-butyl at 15 μM caused 42% reduction of root growth. Haloxyfop-methyl at 5 μM and 15 μM caused 35 and 96% inhibition of leaf growth, respectively. Fluazifop-butyl at same rates caused 19 and 32% inhibition of leaf growth. Haloxyfop-methyl at 5 and 20 μM when applied postemergence caused 20 and 56% reduction of leaf growth, respectively. Fluazifop-butyl at same rates caused 11 and 21% reduction of leaf growth. Haloxyfop-methyl at 20 μM caused 80% reduction of annual blue grass seedlings dry weight whereas fluazifop-butyl caused 40% reduction. Morphological studies showed that postemergence applications of 20 μM of haloxyfop-methyl caused severe tissue injury whereas same rates of fluazifop-butyl caused less injury. Ultrastructural studies showed that haloxyfop-methyl at 20 μM caused disruption, elongation, and reduction of chloroplast thylakoids whereas fluazifop-butyl caused less injury to thylakoids. Acetyl-CoA carboxylase activity from annual blue grass was inhibited by about 40% in the presence of 10 μM haloxyfop acid but fluazifop acid caused 6.5% inhibition. The lipid content was reduced by 56% in seedling treated with 20 μM haloxyfop-methyl whereas fluazifop-butyl caused 19% inhibition. Fluazifop-butyl at all rates caused no loss of lipid classes whereas haloxyfop-methyl at 10 and 15 μM caused loss of phospholipid and glycolipid which are part of the cellular membranes. Haloxyfop caused greater reduction of leaf and root growth, greater degree of tissue injury and chloroplast distortion, greater inhibition of acetyl-CoA carboxylase activity than fluazifop. All these effects lead to degradation of cellular components and eventually to the death of the plant.

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22

Phang, Ing Chia. "Response of Arabidopsis thaliana seedlings to lead exposure." Thesis, University of Canterbury. School of Biological Sciences, 2010. http://hdl.handle.net/10092/4467.

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Lead (Pb) is one of the most commonly occurring, highly persistent and widely distributed heavy metal contaminants in the environment. It has a tendency to bioaccumulate in animals and plants, and potentially, it is able to enter the human food chain where it poses a hazard to public health. Generally, conventional remediation technologies applied to decontaminate heavy metals from groundwater and soils are very costly. Hence, phytoremediation has emerged as an ecologically friendly and economically attractive technology that uses green plants to clean up heavy metal contaminated sites. However, a lack of knowledge of the biological processes associated with plant responses to Pb (e.g. Pb uptake, accumulation, translocation, and tolerance) has been a bottleneck for the application of Pb phytoremediation in the field. A model genetic system of higher plants, Arabidopsis thaliana, was selected to further examine the physiological, biochemical and molecular events occuring in plants under Pb stress. The overall aim of this project was to obtain a better understanding of plant responses to Pb contaminants in the early developmental stages of A. thaliana seedlings. This research encompassed the physiological responses of A. thaliana seedlings to Pb exposure, monitoring their antioxidative defence systems, and investigating the participation of annexin 1 in the response to Pb-mediated oxidative stress. This research also assessed the protective effect of nitric oxide on Pb-induced toxicity of A. thaliana seedlings and it isolated a putative Pb tolerant mutant from an EMS-mutagenized M2 population. A multiexperimental approach was adopted to achieve these objectives. A. thaliana seedlings were grown on modified Huang & Cunningham (1996) nutrient solution containing 0.8% (w/v) agar, with and without Pb(NO3)2, under controlled conditions. A. thaliana seedlings were insensitive to Pb during seed germination. In treatments with up to 200 μM Pb(NO₃)₂, morphological changes and inhibition of root growth were observed in the 7-d-old seedlings. A tolerance index revealed that Pb(NO₃)₂ concentration of 75 μM and higher brought about more than 50% root growth inhibition. Pb was predominantly retained in the roots. Analysis using a graphite furnace atomic absorption spectroscopy indicated that the level of Pb accumulation in A. thaliana roots was greatly dependent on the Pb(NO₃)₂ concentrations, but only a small fraction of the accumulated Pb was translocated to the shoots (18 - 43%). Transmission electron microscopy analysis showed that Pb was mainly immobilized in the cell walls and intercellular spaces. This was interpreted as a mechanism that minimizes the entry of Pb into cells and interference with cellular functions. Pb that gained entry into the cytoplasm was sequestered into the vacuoles. The toxicity of Pb in the cytosol of A. thaliana seedlings was studied by measuring the H₂O₂ and lipid hydroperoxide levels using a microplate reader. When the Pb(NO₃)₂ concentration in the growth medium was 100 μM, the 7-d-old seedlings contained 2.2-fold higher H₂O₂ and 9.6-fold higher lipid hydroperoxide than the control without Pb(NO₃)₂. This was followed by an up-regulation of the activity of antioxidative enzymes, including superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPX), and general peroxidase (POD) by 2.1-, 3.2-, 2.3-, 1.8- and 4.6-fold, respectively, compared with the control. Pb toxicity is known to trigger oxidative stress, but A. thaliana seedlings appeared to be capable of activating cell rescue, defending themselves against harmful oxidative stress and also acclimating to Pb. Data from physiological and biochemical analysis indicate that a combination of avoidance and tolerance mechanisms exists in Pb-treated A. thaliana seedlings to maintain the essential cellular metabolism for survival. Real-time reverse-transcription polymerase chain reaction was used to show the involvement of AnnAt1 in the response of 7-d-old A. thaliana seedlings to a high threshold concentration of Pb. When the seedlings were treated with 100 μM Pb(NO₃)₂, AnnAt1 message levels were up-regulated by 2.12-fold. Pb-mediated oxidative stress may be a component of AnnAt1 gene expression. AnnAt1 potentially could be invoked to reduce the toxic effects of Pb stress by acting as ROS and/or Ca²⁺ signals, as a membrane protector, in detoxification of excessive ROS, or in sequestration of Pb. Pb stress symptoms were less evident in seedlings pre-treated with 1 mM sodium nitroprusside (SNP), a nitric oxide (NO) donor. The present study found that exogenous NO did not alter Pb transport into the plants or efflux pumping of Pb at the plasma membrane. However, NO conferred protection to 7-d-old A. thaliana seedlings primarily by acting as an antioxidant or a signal for actions to scavenge excessive ROS level. The application of exogenous NO before subjecting to 100 μM Pb(NO₃)₂ decreased H₂O₂ back to its original level, and reduced 50% lipid hydroperoxide in the Pb-treated seedlings. As a result, the antioxidative enzyme activities in Pb-exposed seedlings pre-treated with SNP were 23 - 45% lower than those without SNP pre-treatment. Less antioxidative enzyme activities were probably needed to counteract the reduced amount of Pb-induced ROS in A. thaliana seedlings. A post-germination procedure involving prolonged exposure to 150 μM Pb(NO₃)₂ was developed to screen an EMS-mutagenized M2 population of A. thaliana. Potential Pb tolerant mutants were selected based on the ability to grow with their roots penetrating into the medium and maintain purple-green leaves without wilting. A minority of the survivors appeared to go into a resting stage and they seemed to have altered transporters that prevented Pb from entering the cells. Only one putative Pb mutant (M3-1) was recovered from the rescue and set seeds. The M₄ generation of this putative Pb mutant was re-screened for phenotypic confirmation and to determine the regulation of AnnAt1. The 7-d-old putative Pb mutant seemed to display enhanced root and shoot growth in the presence of 150 μM Pb(NO₃)₂ compared to the wild-type seedlings. The transcript level of AnnAt1 in this putative Pb tolerant mutant increased by 2.19-fold when exposed to 150 μM Pb(NO₃)₂.

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23

Ibrahim, Abdelaziz Ali Mohamed 1948. "Vegetative, reproductive and yield responses of tomato (Lycopersicon esculentum L.) seedlings to low temperature and exogenous sucrose treatments." Thesis, The University of Arizona, 1994. http://hdl.handle.net/10150/278454.

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The effects of subjection of 15-day-old plants of tomato (Lycopersicon esculentum L. 'Contessa') to low night temperature (LNT) of 4°C for up to 21 nights and pre-chilling application of 10% sucrose solution on vegetative, reproductive and yield responses were examined under greenhouse conditions. Chilled seedlings exhibited severe inhibition of growth, with the degree of inhibition increasing with length of chilling. While sucrose treatment (ST) reduced such inhibition and promoted subsequent recovery, it transiently inhibited growth of the unchilled controls. In the long-term, inhibition of growth was observed only for the 0%-sucrose-treated plants cooled for 21 nights. Although LNT lowered the position of the first inflorescence in a direct relation to duration of exposure, this effect was reduced by ST. LNT had no lasting effects on the reproductive and productivity responses of the first two inflorescence (FTI), earliness of flowering, or potential yield and quality. ST promoted flowering of only the 21-day-cooled plants as well as numbers of flowers, fruit set and large fruit responses of FTI. The results indicate that, although early chilling stunts seedling growth, plants may recover at a later favorable temperature without loss to their reproductive capacity or yielding potential.

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24

French, Robert John. "Leaf senescence and water stress in wheat seedlings /." Title page, contents and summary only, 1985. http://web4.library.adelaide.edu.au/theses/09PH/09phf875.pdf.

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25

Joesting, Heather M. "Physiology and Leaf Characteristics of American Chestnut ( Castanea Dentata (Marsh.)Borkh.) Seedlings, Saplings, and Mature Trees in Ohio and Wisconsin." Ohio University / OhioLINK, 2005. http://www.ohiolink.edu/etd/view.cgi?ohiou1125441507.

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26

Ahmed, Aisha Moustafa 1950, and Aisha Moustafa 1950 Ahmed. "Effects of salinity, watering regimes and soil types on growth of Cupressus sempervirens, Thuja orientalis, and Casuarina equisetifolia seedlings." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282376.

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Digitization note: pgs. 62 & 91 missing from paper copy and not available for rescanning. Effects of three levels of irrigation frequency; five levels of increasing NaCl (max 8000 ppm) in the irrigation water; and, two different soil types on the growth and survival of Italian Cypress Cupressus sempervirens, Oriental Arborvitae Thuja orientalis, and She-Oak Casuarina equisetifolia tree seedings were studied under greenhouse conditions. There were significant differences between the species throughout the stress period with regard to the evaluated parameters. Height, diameter growth, and leaf water potential in all species were reduced by increasing water and salt stress throughout the stress period. Reductions in total, shoot and root dry weight by water and salt stress were significant. Higher reductions were associated with higher water or salinity stress level. However, the species differed in their response to the stress treatments. Thuja had the lowest reductions in all measured growth parameters, followed by Casuarina and Cupressus. Water and salt stress treatments affected foliage tissue ion concentrations in all seedlings. N, P, K, Ca, Mg, Na, and Cl decreased as water stress level increased (except for, Na and Cl in Brazito soil). However, Ca, Mg, Na and Cl ion concentrations increased as the salinity level in the irrigation water increased. N and P decreased with increasing salinity and K was selectively accumulated. The seedlings' health declined with increasing stress treatment level. NaCl treatments caused foliar injury, which increased as the concentration of NaCl in the irrigation water increased. Thuja showed the least injury followed by Casuarina. Mortality was limited to Cupressus seedlings on both soil types. More mortality was noted with the increase in irrigation frequency and salinity level of the irrigation water. Thuja and Casuarina seedlings survived to the highest salinity level (8000 ppm NaCl), but with visible injury. Soil types affected all seedlings morphological parameters, total water potential, and foliage ion concentrations, except for P and Ca. All seedlings (except for Casuarina root dry weight) planted in Pima soil maintained higher growth and better overall health condition than on Brazito soil. Also, total water potential reached lower values in all species planted in Brazito soil rather than on Pima soil. Foliage Na and Cl concentrations on Brazito soil exceeded those on Pima soil. Survival of Cupressus seedlings was less on Brazito soil than on Pima soil. Overall, Cupressus growth was reduced the most on Brazito soil as compared with Pima soil. Growth of Casuarina was the least adversely affected on Brazito soil.

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27

Viktor, Aleysia. "Physiological and metabolic factors determining nitrogen use efficiency of tomato seedlings grown with elevated dissolved inorganic carbon and different nitrogen sources." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52999.

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Thesis (MSc)--University of Stellenbosch, 2002. ENGLISH ABSTRACT: The aim of this study was to determine (l) the influence of elevated dissolved inorganic carbon (DIC) on the nitrogen use efficiencies (NUE) of tomato seedlings grown with different nitrogen sources, (2) how changes in the regulation and activities of nitrate reductase (NR), phosphoenolpyruvate carboxylase (PEPc), carbonic anhydrase (CA) and subsequent changes in metabolites would account for observed changes in NUE, and (3) to what extent elevated DIC contributed to the carbon budget of plants grown with different nitrogen sources. Lycopersicon esculentum cv. Fl44 seedlings were grown in hydroponic culture (pH 5.8) with 2 mM of either N03- or NH4 + and the solutions were aerated with either 0 ppm or 5000 ppm CO2 concentrations. The similar NUEs of NH/-fed plants grown with either root-zone CO2 concentration were largely due to their similar RGRs and N uptake rates. Elevated root-zone DIC had an initial stimulatory effect on N~ + uptake rates, but it seems as if this effect of DIC physiological processes was cancelled out by the toxic effect of unassimilated NH/. The NUE for N03--fed plants supplied with 5000 ppm root-zone CO2 was higher relative to 0 ppm root-zone CO2 and it was possibly due to the higher relative growth rates for similar N uptake rates of 5000 ppm compared to 0 ppm root-zone CO2. Nitrate-fed plants grown with 5000 ppm compared to 0 ppm root-zone CO2 had higher in vivo NR and in vitro NR and PEPc activities. These increases in enzymes activities possibly lead to increases in organic acid synthesis, which could have been used for biomass accumulation. This would account for the increased relative growth rates of N03--fed plants grown with 5000 ppm compared to 0 ppm root-zone CO2. The increasing rootzone CO2 concentrations resulted in the Ó15N values of NH/-plants becoming more positive indicating an absence of enzymatic discrimination. This may have been due to the inhibitory effect of DIC on Nll,+ uptake, causing plants to utilise both internal isotopes equally. The Ól3C studies showed that PEPc contributed equally to both N03-- and NH/-fed plants over the long term. From this it can be concluded that the lower NUE of NH/-compared to N03--fed plants grown with 5000 ppm root-zone C02 was due to increased N uptake and exudation of organic compounds into the nutrient solution. Experiments with 813C also showed that at increasing rootzone CO2 concentrations, PEPc made a bigger contribution to the carbon budget via the anaplerotic reaction. AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om (1) die invloed van verhoogde opgeloste anorganiese koolstof dioksied (DIC) op die stikstofverbruiksdoeltreffenheid (NUE) van plante wat op verkillende stikstofbronne gekweek is, te bepaal. (2) Veranderinge in die regulering van nitraat reduktase (NR), fosfo-enolpirovaatkarboksilase (PEPc) en karboonsuuranhidrase (CA) is bestudeer en gekorreleer met waargeneemde verskille in NUE. (3) 'n Beraming van die mate waartoe verhoogde DIC bydra tot die koolstofbegroting van plante, gekweek op verskillende stikstofbronne, word bespreek. Lycopersicon esculentum cv. F144 saailinge is in waterkultuur (pH 5.8) met 2 mM N03- of NH/ gekweek en die oplossings is alternatiewelik met 0 ppm of 5000 ppm CO2 belug. Die NUEs van plante gekweek met NH/ en belug met albei C02 konsentrasies was vergelykbaar grootliks as gevolg van hulooreenkomstige relatiewe groeitempo's en Nopname. DIC het aanvanklik NH/ opname gestimuleer, maar enige latere stimulerende effek van DIC op fisiologiese prosesse was klaarblyklik uitgekanselleer deur N~ + toksiteit veroorsaak deur vertraagde assimilasie. Die NUE van plante gekweek met N03- en 5000 ppm CO2 was hoër as dié van plante gekweek met N03- en 0 ppm CO2. Dit is moontlik gekoppel aan hoër relatiewe groeitempo's teenoor onveranderde N opname tempo's. Plante gekweek met N03- en 5000 ppm CO2 het hoër in vivo NR en in vitro NR en PEPc aktiwiteite getoon as plante gekweek met N03- en 0 ppm CO2. Bogenoemde toenames in ensiem aktiwiteite word verbind met biomassa toename deur verhoogde organiese suur sintese. Dit bied 'n moontlike verklaring vir die hoër relatiewe groeitempo's van plante gekweek met N03- en 5000 ppm CO2 teenoor plante gegroei met N03- en 0 ppm CO2. Die 015N waardes van plante gekweek met NH/ en 5000 ppm CO2 was meer positief as dié van plante gekweek met Nl-l,+ en 0 ppm CO2 wat gedui het op die afwesigheid van ensiematiese diskriminasie. Dit kon as gevolg gewees het van die vertragende effek van DIC op Nl-la + opname wat daartoe sou lei dat die plante beide isotope eweveel inkorporeer. Eksperimente met ol3C het getoon dat PEPc oor 'n lang tydperk eweveel begedra het tot die koolstofbegroting van plante gekweek met beide N03- and N~+. Hiervan kan afgelei word dat die laer NUE van plante gekweek met NH4 + en 5000 ppm C02 in vergelyking met dié van plante gekweek met N03- en 5000 ppm CO2 die gevolg was van verhoogde NH/ opname en uitskeiding van aminosure in die voedingsoplossing. Eksperimente met 0"c het ook getoon dat verhoogde DIe konsentrasies die bydrae van PEPc tot die plant se koolstofbegroting laat toeneem.

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Arruda, Natália. "Avaliação da estrutura e do potencial fisiológico de sementes de crotalária por meio de recursos de análise de imagens." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-14032013-131905/.

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A utilização de procedimentos rápidos e confiáveis para análise de sementes é fundamental para a tomada de decisões nas diferentes etapas do processo produtivo e definição do destino dos lotes de sementes. Neste sentido, os objetivos desta pesquisa foram: a) avaliar a estrutura de sementes de crotalária, utilizando raios X para avaliação das partes da semente, identificação de possíveis danos causados por injúrias mecânicas, por percevejo e tecidos deteriorados nas sementes e sua relação com a germinação; b) verificar a possibilidade de utilização do sistema computadorizado de análise de plântulas (SVIS®) para detectar diferenças de vigor entre lotes de sementes de Crotalaria juncea, em comparação com as informações fornecidas por testes tradicionalmente utilizados para a espécie. Foram utilizadas seis lotes de sementes de crotalária do cultivar IAC-KR1, tanto para avaliação da estrutura de sementes quanto para a análise de imagens de plântulas. As análises relativas à morfologia interna das sementes foram realizadas em apenas uma época, no início da pesquisa, ao passo que aquelas relativas ao sistema computadorizado de imagens de plântulas e demais testes de vigor foram realizados em duas épocas, espaçadas de quatro meses. Inicialmente as sementes foram submetidas ao teste de raios X e ao teste de germinação. As plântulas normais, anormais e sementes mortas foram fotografadas e analisadas paralelamente às imagens radiográficas das sementes. Na segunda etapa da pesquisa, os seis lotes foram submetidos a testes de germinação e de vigor (primeira contagem de germinação, envelhecimento acelerado, emergência de plântulas em areia e condutividade elétrica). Para determinação do vigor das sementes por meio do SVIS®, as plântulas foram avaliadas aos três e quatro dias após a semeadura do teste de germinação, sendo obtidos dados referentes ao índice de uniformidade de desenvolvimento, vigor e comprimento de plântulas. Concluiu-se que a análise de imagens de raios X permite identificar danos mecânicos, por percevejo e tecidos deteriorados em sementes de crotalária e relacioná-las com a germinação; o SVIS® é uma alternativa viável para a avaliação do vigor de sementes de crotalária. Fast and reliable procedures for analyzing seeds are fundamental for taking decisions during the different production stages and defining the destination of seed lots. Therefore, the objectives of this study were: a) to study the structure of sun hemp seeds with X-ray to evaluate the seed parts and identify possible damage caused by mechanical injuries, stink bugs and deteriorated tissues and their relation to germination; b) verify the possibility of using a computerized seedling analysis system (SVIS®) to detect differences in vigor between seed lots of Crotalaria juncea, and compare the results with those obtained from vigor tests used for the species. Six lots of the sun hemp cultivar IAC-KR1 were used to evaluate seed structure and also to analyze seedling images. The internal morphology seed was analyzed only at the beginning of the study whereas the computer analysis of seedling images and the other vigor tests were done at two different times, four months apart. The seeds were first submitted to X-ray and germination tests. Normal and abnormal seedlings and dead seeds were photographed and analyzed at the same time as the seed X-ray images. In the second stage of the study, the six lots were submitted to germination and vigor (first germination count, accelerated aging, seedling emergence in sand and electrical conductivity) tests. To determine the seed vigor using the SVIS®, the seedlings were evaluated three and four days after sowing for the germination test, when data on the uniformity development index, vigor and seedling length were obtained. It was concluded that the analysis of X-ray images is efficient for identifying mechanical damage, stink bug damage and deteriorated tissues and allowed to establish an association between their occurrence and germination; the SVIS® is a viable alternative for evaluating the vigor of sun hemp seeds.

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29

Maarri, Khalil al. "Micropropagation in vitro du pommier (M9), du poirier ("williams" et "passe crassane") et du cognassier de Provence : problèmes posés par l'état physiologique du matériel." Paris 6, 1986. http://www.theses.fr/1986PA066057.

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Au cours du travail présenté dans ce mémoire, nous sommes parvenus à obtenir, de façon systématique, la micropropagation in vitro et l'acclimatation ex vitro non seulement des poiriers juvéniles issus de pépins de "passe crassane", mais aussi du cognassier de Provence et de deux cultivars de poirier, "williams" et "passe crassane". Les conditions de culture concernant les différentes phases de la micropropagation et l'acclimatation ont été étudiées. Plusieurs problèmes d'ordre physiologique (dormance des bourgeons in vitro, anomalie des pousses formées, nécrose des apex) ont pu être surmontés ou limités.

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30

WANG, PING-YUAN, and 王品元. "Effect of Abscisic Acid on Healing Physiology of Tomato Grafted Seedling." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/fab3vu.

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碩士 國立宜蘭大學 園藝學系碩士班 106 This research aimed to study the effects of foliar application with abscisic acid (ABA) to the tomato grafted seedlings to reduce physiological stress during the healing period. In this test, tomato ‘Yu Nu’ was used as scion and eggplant ‘EG203’ was used as stocks. Grafted seedlings were applied with 0 (control), 500, 1000 and 1500 mg L-1 ABA, respectively, and then placed in the accumulation chamber. Record physiological changes of tomato grafted seedling within 14 days after grafting. The results showed that foliar application with ABA were reducing the tomato grafted seedlings withering immediately and improve the graft survival rate significantly. The structural development of the graft union formation in tomato plants is studied. Longitudinal section diagrams from graft union showing graft gap at the 1st-3rd day after grafting. Longitudinal section of the graft union showing the cell division situation is obvious at the 5th-7th day after grafting. Longitudinal section of the graft union showing that tissue of stock and scion mixed each other, parts of graft union were connected at the 9th-13th day after grafting. The results of scion and rootstock xylem bundles stained with blue flower dye value showed that the grafted seedling of 500 mg L-1 ABA treatment had significantly higher at the 13th day after grafting. The results of functional vascular connections showed that the grafted seedling of 1000 mg L-1 ABA treatment had significantly smaller gap of the sugar content between scion and rootstock at the 13th day after grafting. The content of proline in the control group was significantly higher than treatment group at initial stage after grafting. The results of superoxide dismutase, peroxidase, and ascorbate peroxidase activity showed that control, 500, 1000 mg L-1 ABA treatment reached the highest value at the 7th day after grafting. The results of chlorophyll fluorescence parameter showed that all treatment had obviously lower Fv/Fm at initial stage after grafting. At 9th day, Fv/Fm recovered gradually. The results showed that the foliar application with ABA at appropriate concentrations reduced the tomato grafted seedlings withered ratio, proline content, and improve the graft survival rate significantly. In addition, 500, 1000 mg L-1 ABA treatment had better performance of promote nutrient transport. The results of this research can be improved the quality of grafted seedlings with positive benefits.

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31

Jacobs, Douglass Frederick. "Influence of root architectural development on Douglas-fir seedling morphology and physiology /." 2001. http://hdl.handle.net/1957/13332.

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Chen, Chang-Chang, and 陳昶璋. "The Effect of Light Quality on Morphology and Photosynthetic Physiology in Rice Seedling." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/60563258906732268209.

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博士 國立臺灣大學 農藝學研究所 102 Our objective in this study was to evaluate the effect of light quality on the morphology and photosynthetic physiology of rice seedlings. We examined the growth, development, and metabolic responses of rice seedlings to varying light quality firstly. Seedlings were hydroponically cultured under red (R) light-emitting diodes (LED), green LED (G), blue LEDs (B), and red + blue LED (RB) inside growth chambers. Red light induced shoot elongation. B light inhibited shoot elongation and promoted health index values. B light also resulted in higher total protein content in tested leaves compared to RB. Blue light enhanced the effective quantum yield of PSII photochemistry (ΦPSII) and photochemical quenching (qP) while reducing non-photochemical quenching (NPQ) in seedling leaves. The responses of rice seedlings to green and red light were quite similar. The anthocyanin content of seedling leaves was observed to be highest in RB but less so in R and B, the latter two being even lower than in G. Different wavelengths mediated the chlorophyll (Chl) a/b ratio of the leaves. Light quality influenced photosynthetic potential and nitrogen metabolism, which are related to water-use efficiency (WUE) and nitrogen uptake. We further investigated the response of time-integrated WUE, 13C discrimination (Δ13C), and nitrogen uptake in hydroponic seedlings of rice grown under different light treatments with fluorescent light (FL) as the control. The WUE response was highest for seedlings grown under R light, then (in decreasing order) seedlings grown under G, RB, and B light. WUE had a significantly positive correlation with Δ13C except under FL light (P<0.01). Nitrogen content (%N) and δ15N values were used to estimate the effects of fertilizer uptake under different lighting conditions. The amount of N in seedlings derived from fertilizer (Nf) was highest under B light and lowest under R light. Therefore, we conclude that blue light may increase stomatal conductance and transpiration, decrease WUE, and promote root N uptake. The dynamics of Chl, biosynthetic intermediates (protoporphyrin IX, PPIX; magnesium protoporphyrin IX, MGPP; protochlorophyllide, Pchlide), degradation intermediates (chlorophyllide, Chlide; pheophytin, Phe; pheophorbide, Pho), and carotenoids (Car) in leaves of rice seedlings were also investigated. Lower levels of Chl and Car in leaves were observed under G lighting. Light quality did not mediate the mole percent of porphyrins in biosynthetic pathways. Lower Phe/Chlide ratios were observed under G and FL lighting conditions, indicating that green-enriched environments may up-regulate the Chlide degradation route in leaves. In order to clarify the effect of green light on the Chl degradation pathway, seedlings were grown under equal intensity (40 μmol m-2 s-1) of red and blue light with four levels of green light intensity (0, 20, 40, and 60 μmol m-2 s-1). Some morphological traits and photosynthetic physiology were also investigated at the same time. Sheaths of rice seedling leaves became elongated and leaves grew more erectly under red and blue light with increasing green light intensity. These morphological traits are known as shade avoidance symptoms (SAS). Lower Chl, decreasing &;#1060;PSII, and increasing NPQ were also observed under increasing green light intensity. Higher Chlide levels and lower Phe/Chlide ratios were observed under increases in green light intensity. These results indicated that green light induced SAS and mediated Chl degradation routes in rice seedlings.

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Omi, Steven K. "Effects of fall lifting and long-term freezer storage on ponderosa pine seedling physiology and quality /." 1990. http://hdl.handle.net/1957/11345.

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Lin, Heng-Liang, and 林恆亮. "Effects of Boron on the Physiology and Nutritional Status of Papays(Carica papaya L.) seedling." Thesis, 1988. http://ndltd.ncl.edu.tw/handle/88720068844969943001.

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碩士 國立中興大學 園藝學研究所 76 In Taiwan, an aggregate of 6300 hectares has been allocated for the cultivation of papaya. The plant, however, is devastated by ring spot virus diseases on the ond hand and plaqued occasionally by boron deficiency, which leading to the decreases in fruit quality and yields, on the other. In order to probe the effects of boron on the physiology of papaya, endeavors have been made to investigate the changes that boron deficiency could bring to metabolism, and inorganic nutritional status of the crop. 　　The results showed, when papaya was subjeted to boron deficiency for 21 days, symptoms such as yellowing of new leaves, tissues texture turning hard and brittle, growth retardation and the formation of brown, coralshaped roots were evident. Paraffin method demonstrated the primodia, in addition to being undergrown, were hollow and broken. At 8 ppm of boron, the tips and edges of the old leaves were yellow and necrosis. The development of primodia, as revealed by paraffin method, had taken place but not reached the stage of ompletion. Phloroglucin stain indicated lignin content in 0 ppm boron treated papaya was high and dense, which also showed a tendency of penetrating into the inward of the tissues. The growth of the boron-starvated plants was stunted. Their surface areas were around 520 cm2 and stopped to grow any larger. The fresh and the dry weight of their roots and the parts of plant above ground were lighter than that of their normal counter-parts. The same is true with their water content; the boron deficient plants contained less water. 　　In the course of boron deficiency, nitrogen in the form of ammonia rose sharply after 14 days of treatment whereas soluble proteins on the other hand decreased after 21 days of incubation. The amounts of free amino acids in the plant were higher as the deficiency proceeded to the 28th and 35th days. However, there was no perceptible change in nitrate level in plants which under went different treatments. The soluble carbohydrates in leaf surged drastically beginning with the 7th day of the treatment and remained high for the rest experimental period. However, the concentrations of reducing sugars did not show any sign of increase until the 14-21 day period was reached. Low boron regime inhibited glutamine synthetase and acid phosphatase activities but stimulated the activity of peroxidase. Interextingly, it had no effect whatsoever on nitrate reductase. 　　An assay of mineral elements in papaya leaf indicated that low boron uptake had led to the drop of N, P, Ca, Cu, Fe, B contents but not the levels of K, Mg, Mn and Zn. Furthermore, the conditions were harmful not only to growth but also to nitrogen and carbon metabolisms, enzyme activities and ion composition of papaya.

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Liu, Cheng-Yu, and 劉政侑. "Effects of sowing rate and seedling per hill on physiology and agronomic characters of rice." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/61206834485239777329.

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碩士 國立嘉義大學 農藝學系研究所 97 This study is to determine the best sowing rate and quantities oftransplants for paddy rice (Oryza sativa) Tainan No. 11 in and to its agronomic traits. The seedling tray applying to current mechanicaltransplanting of paddy rice seedling was utilized in this test. Each seedling tray used different planting densities in 200 g, 250 g, 300 g, 350 g respectively. We planted for single, triple and mechanical transplanting seedlings for multeity, then observing the physical changes and influences of its agronomic traits in each groups after seedling transplanting. It showed that the 200 g seedling rate had better agronomic traits and higher yield than others. Resides comparison of cropping yield in three different transplanting quantities, in first-crop paddy rice, the highest yield is three,second-crop is multeity. The result suggested that the 200 g seedling rate and mechanical transplanting of rice seedling had the best agronomic traits,offering a fine example for paddy rice breeder and agriculturist.

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CHUNG, HSIN-YING, and 鍾興穎. "Effects of salinity on the growth and physiology in seedling of melon(Cucumis melo L.)." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/66590482048409797813.

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碩士 國立宜蘭大學 園藝學系碩士班 97 Studied on the different pre-treatments of ‘New Century’ and ‘Sweetie’ seedlings of melon (Cucumis melo L.) growth and ions concentration , treated with different concentrations (0.2, 9.0, 13.5 dSm-1) of deep sea water (DSW) and Sodium Chloride (NaCl). The results showed that the fresh weight, dry weight, chlorophyll contents, protein contents of melon seedlings decreased along with increasing of the salt concentration, but carbohydrate concentration, proline concentration increased. The proline concentration of ‘Sweetie’ seedling significantly increased in the high salinity treatment ; carbohydrate concentration of ‘New Century’ significantly increased in the high salinity treatment. This probably two different melons used different physiological mechanism to keep osmotic adjustment for increasing salt tolerance. The reductive rate of fresh weight less ‘New Century’ than ‘Sweetie’ in the same salinity treatment. Might ‘New Century’ is more salt tolerant than ‘Sweetie’. Low salinity of deep sea water treatments melon seedling had higher chlorophyll contents, protein contents and survival rate than Sodium Chloride treatment, conjecturing that deep sea water might be a moderate salinity solution. The melon seeds of ‘New Century’ and ‘Sweetie’ primed with salt solution, might significantly increase survival rate, root / shoot ratio and reduction of electrolyte leakage in salt environment, specially Sodium Chloride primed combine deep sea water to show the better salt tolerance. Na+ and Cl- contents significantly accumulate in the stem when exposed to salt. Melon seedling treated with salt conditioning(4.5 dSm-1) could significantly increase survival rate in low salinity, significantly increase proline contents in high salinity. The results showed melon seed use salt pre-treatment (priming+conditioning) could increasing salt tolerance.

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Dinger, Eric J. "Characterizing early-seral competitive mechanisms influencing Douglas-fir seedling growth, vegetation community development, and physiology of selected weedy plant species." Thesis, 2012. http://hdl.handle.net/1957/29479.

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Three studies were conducted to characterize and present early-seral competition between Douglas-fir seedlings and the surrounding vegetation communities during Pacific Northwest forest establishment. The first experiment served as the foundation for this dissertation and was designed to quantify tradeoffs associated with delaying forest establishment activities by introducing a fallow year in order to provide longer-term management of competing vegetation. A range of six operationally relevant treatments were applied over two growing seasons that included in the first (1) a no-action control, (2) a spring release only, (3) a fall site preparation without sulfometuron methyl followed by a spring release, as well as (4) a fall site preparation with sulfometuron methyl and a spring release. In the second year, there was (5) a fall site preparation without sulfometuron methyl followed by a spring release and also in the second year (6) a fall site preparation with sulfometuron methyl and a spring release. Treatments 5 and 6 were left fallow without planting during the first year. These treatments were applied in two replicated experiments within the Oregon Coast Range. After adjusting for initial seedling size, year-3 results indicated that plantation establishment and competition control immediately after harvest (i.e. no fallow period) enabled seedlings to be physically larger than those planted after a one year delay. At the Boot study site, limiting vegetation below 20% for the first growing season improved year-3 Douglas-fir seedling stem volume over 273 cm³. Delaying establishment activities one year and reducing competing vegetation below 11% enabled seedling volume after two years to be statistically the same as three year old seedlings in the no-action control, a volume range of between 148 to 166 cm³. Delaying forest establishment at Jackson Mast improved seedling survivorship over 88% when a spring heat event reduced survivorship of trees planted a year earlier to less than 69%. The combined effect of applying a fall site preparation and spring release was necessary to reduce competitive cover below 10% in the year following treatment and provided longer-lasting control of woody/semi-woody plants. Less intense control measures (i.e. no-action control and treatment 2) were not able to restrain woody/semi-woody plant cover which grew to nearly 40% at Boot and over 24% at Jackson Mast in three years. No treatment regime provided multi-year control of herbaceous species. Including sulfometuron methyl in the fall site preparation tank-mix did not have a negative effect on seedling growth or provide significant reductions in plant community abundance in the year following application when compared to similar regimes that did not include the chemical. Delaying establishment lengthened the amount of time associated with forest regeneration except on a site that accentuated a spring heat event. In the second study, horizontal distance and azimuth readings provided by a ground-based laser were used to stem map seedling locations and experimental unit features at Boot. These data were used to create a relative Cartesian coordinate system that defined spatially explicit polygons enabling, for the first time, the ability to collect positional data on competing forest vegetation within an entire experimental unit. Deemed "vixels" or vegetation pixels, these polygons were assessed for measures of total cover and cover of the top three most abundance species during the initial three years of establishment. An alternate validity check of research protocols was provided when total cover resulting from this vixel technique was compared to a more traditional survey of four randomly located subplots. The resulting linear regression equation had an adjusted R² of 0.90 between these two techniques of assessing total cover. When compared within a treatment and year, total cover differed by less than 12 percentage points between the two techniques. Analysis of year-3 woody/semi-woody plant cover produced by the techniques led to identical treatment differences. Two treatments resulted in woody/semi-woody cover of approximately 1500 ft² by the vixel method and nearly 40% cover by the subplot method while the remaining four treatments were grouped below 600 ft² or 20% cover, respectively. With continued refinement, these techniques could visually present forest development through all phases and provide long-term information used to bolster growth and yield models, measures of site productivity, as well as community ecology research. The third study evaluated the season-long gas exchange and biomass partitioning of four weedy plant species capable of rapidly colonizing Pacific Northwest regenerating forests. Cirsium arvense, Cirsium vulgare, Rubus ursinus and Senecio sylvaticus were studied at two sites. A greenhouse was used to introduce two levels of irrigation (well-watered and droughty). These species were also studied while growing among a larger vegetation community at a field site. Irrigation treatments had little impact on gas exchange rates. Species achieved maximum photosynthetic rates of 30, 20, 15 and 25 μmol CO₂ m⁻² s⁻¹ (respectively) prior to mid-July coinciding with an active phase of vegetative growth. As the season progressed, photosynthetic rates declined in spite of well-watered conditions while transpiration rates remained relatively consistent even when soil water decreased below 0.25 m³ H₂O/m³ soil. Water use efficiency was high until late-July for all study species, after which time it decreased below 5 μmol CO₂ · mmol H₂O⁻¹. Multi-leaf gas exchange measurements as well as biomass data provided a holistic view of plantlevel mechanisms used to shunt activity toward developing tissues. Herbaceous species had assimilation rates that differed vertically (within each species) by as much as 10 to 20 μmol CO₂ m⁻² s⁻¹ from July to September as lower leaves senesced in favor of those higher on study plants. Specific leaf area was greatest in June for all species then declined indicating species placed little effort into sacrificial early season leaves when compared to those higher on the plant that could continue to support flowering or vegetative growth. The study of seasonal gas exchange in the presence of declining water availability has helped to describe competitive mechanisms at work during forest regeneration as well as provide physiologic support for the application of vegetation management regimes. Graduation date: 2013

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"Physiological Response to Environmental Stress in Drylands Ecosystems: Examining Prosopis velutina Seedling Responses to Temporal Water Availability Gradients." Master's thesis, 2020. http://hdl.handle.net/2286/R.I.57030.

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abstract: Climate change is increasing global surface temperatures, intensifying droughts and increasing rainfall variation, particularly in drylands. Understanding how dryland plant communities respond to climate change-induced rainfall changes is crucial for implementing effective conservation strategies. Concurrent with climate change impacts on drylands is woody encroachment: an increase in abundance of woody plant species in areas formerly dominated by grasslands or savannahs. For example, the woody plant, Prosopis velutina (velvet mesquite), has encroached into grasslands regionally over the past century. From an agricultural perspective, P. velutina is an invasive weed that hinders cattle forage. Understanding how P. velutina will respond to climate change-induced rainfall changes can be useful for management and conservation efforts. Prosopis velutina was used to answer the following question: Is there a significant interactive effect of mean soil water moisture content and pulse frequency on woody seedling survival and growth in dryland ecosystems? There were 256 P. velutina seedlings sourced from the Santa Rita Experimental Range in southern Arizona grown under four watering treatments where mean and pulse frequency were manipulated over two months. Data were collected on mortality, stem height, number of leaves, instantaneous gas exchange, chlorophyll fluorescence, biomass, and the leaf carbon to nitrogen (C:N) ratio. Mortality was low across treatments. Pulse frequency had less impact across response variables than the mean amount of water received. This may indicate that P. velutina seedlings are relatively insensitive to rainfall timing and are more responsive to rainfall amount. Prosopis velutina in the low mean soil moisture treatments lost a majority of their leaves and had greater biomass allocation to roots. Prosopis velutina’s ability to survive in low soil moisture conditions and invest in root biomass can allow it to persist as drylands are further affected by climate change. Prosopis velutina could benefit ecosystems where native plants are at risk due to rainfall variation if P. velutina occupies a similar niche space. Due to conflicting viewpoints of P. velutina as an invasive species, it’s important to examine P. velutina from both agricultural and conservation perspectives. Further analysis on the benefits to P. velutina in these ecosystems is recommended. Dissertation/Thesis Masters Thesis Plant Biology and Conservation 2020

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Cheng, Deng Guo, and 程登國. "Studies on the Physiology of Stresses in Rice Seedlings." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/63080771935014387709.

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碩士 國立臺灣大學 農藝學研究所 95 本論文分兩部分，第一部分是以台中在來一號（少陽 7sa 打 va L . , cv . Ta 1 chung Nat ivel , TNI ）水稻切離葉片為材料，探討 polyethylene glycol 6000 ( PEG ）處理對切離葉片生理反應之影響，同時亦探討多元膠與 PEG 逆境問之關係。第二部分則 TNI 以及台農六十七號（少陽 7sa 打 vaL . , cv . Tainung67 , TNG67 ) 水稻幼苗為材料。探討水稻幼苗葉片黃化是否與鋅和鐵含量降低有關。 PEG 處理水稻切離葉片造成相對水分含量之降低，過氣化氫與 MDA 含量增加，葉綠素以及蛋白質降解，抗氣化酵素（ SOD 、 GR 、 APX 以及 CAT ）比活性增加，脫落酸、脯膠酸以及銨離子含量之增加，同時也影響與銨離子之累積相關酵素（ GS 、 PAL 與 protease ）活性或比活性。 Putrescine 與 spermidine 不會影響 PEG 所造成之 MDA 含量增加，而 spermine ( SPM ）則會降低 PEG 所導致的 MDA 含量增加。 SPM 可抑制 PEG 所造成的過氣化氫含量增加，葉綠素與蛋白質降解，抗氣化酵素酵素比活性增加，脫落酸與銨離子增加， GS 活性降低，以及 PAL 與 protease 比活性增加。然而 SPM 不影響 PEG 所造成脯膠酸之累積。氣化鎘（ 50 酈）處理 TNI 水稻幼苗表現葉片黃化現象，葉片鎘含量增加，鋅與鐵含量降低，但以相同氣化鎘濃度處理 TNG67 水稻幼苗，則不會表現葉片黃化現象，葉片鎘、鋅與鐵含量也不改變。這些結果說明 TNI 水稻幼苗葉片黃化可能與葉片內鋅與鐵含量降低有關。

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Jimenez-Casas, Marcos. "Effects of NaCl on growth and physiology of Pinus leiophylla seedlings." Phd thesis, 2009. http://hdl.handle.net/10048/446.

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Identification of salt- resistant tree species and genotypes is needed for rehabilitation of lands affected by salinity in Mexico. This dissertation consists of four studies for analyzing the responses of Pinus leiophylla seedlings to salt. In the first study, resistance to salt stress was studied in six-month-old seedlings from eight different sources of seed collected from the areas with contrasting precipitation levels. Plants from the xeric areas were shorter and had smaller stem diameters but were less sensitive to salt stress and recovered faster from salt injury compared with the plants from mesic sites, suggesting that morphological and physiological adaptations to drought were helpful with salt stress resistance. In the second study, fascicle needle production and tissue ion accumulation were examined in NaCl-treated three-month-old seedlings from two populations of the xeric origin and two populations from the mesic areas. Seedlings from the xeric population of San Felipe developed fewer fascicles and had shorter needles compared with seedlings from the remaining three populations. NaCl treatment delayed the emergence of fascicles and reduced the fascicle needle production and needle length. However, the extent of needle injury and ion accumulation in shoots were lower in the San Felipe seedlings compared with the other studied populations. In the third study, the effects of branch pruning and seedling size on total transpiration and accumulation of Na+ and Cl- in tissues were examined. Total plant transpiration, as affected by plant size and branch pruning, was correlated with Na+ and Cl- needle concentrations and needle necrosis. Branch pruning reduced ion accumulation in the shoots and needle necrosis levels in short seedlings but not in the tall seedlings. In the fourth study, sprouting and physiological responses of 16 month-old-seedling to salt were examined. NaCl treatment concentrations of 100, 150, and 200 mM reduced gas exchange and root hydraulic conductance, caused needle injury and triggered sprouting of adventitious shoots. Sprouting from the upper parts of the main stem and lateral branches was three times greater with 100 and 150 mM NaCl compared with 200 mM NaCl treatment but, at the base of the stem, sprout numbers were similar for all NaCl treatments.

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Jiménez-Casa, Marcos. "Effects of NaCl on growth and physiology of Pinus leiophylla seedlings." 2009. http://hdl.handle.net/10048/446.

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Thesis (Ph. D.)--University of Alberta, 2009. Title from pdf file main screen (viewed on July 24, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Renewable Resources, University of Alberta." Includes bibliographical references.

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Li, An-Shiang, and 李安翔. "Accommodation of Different Light Intensities on Growth and Physiology of Three Hardwood Species Seedlings." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/05346581437875564123.

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碩士 國立中興大學 森林學系所 98 Many scholar proposed the building of multi-storued stand to obtain the purpose if stabilizing forest stand. This study discussed the physiology response of Myristica cagayanensis, Michelia formosana and Melia azedarach having different ecology habit to different light intensity by different artificial treatment of shading, to provide the reference of the tree species selecting when building multi-storied stand in different gaps. The experiment results indicated that M. cagayanensis has the higher growth and the tree percent in relative luminosity 20~40 %, when under the full sunlight growgh is limited. M. formosana have the higher growth and the tree percent above relative luminosity 20% and the M. azedarach relative luminosity above 40% have the good growth quantity, when under relative luminosity 5% growgh is limited. The characteristic of photosynthesis indicate that M. cagayanensis in relative luminosity 5~40 % and M. azedarach relative luminosity above 40% show greater maximum photosynthetic rate. M. formosana does not have the remarkable difference in the luminosity. The part of diurnalvariation oh chlorophyll fluorescence indicate that three species seedling growthing under full sunlight were all show that suffering photoinhibition obviously, and the midday value of Fv''/ Fm'' was below 0.7, the M. cagayanensis in relative luminosity above 20% show daybreak the datum value is lower than the normal value (0.832 ±0.004), demonstrated that the photosynthesis reaction center injury, does not adapt grows in high light environment. In the sun light M. formosana and M. azedarach have high NPQ in noon. Summarizing the above results, M. cagayanensis shows the characteristic of shade-tolerant tree species, when builds the multi-storued stand forest, suggested that plants it in the hole is small the relative luminosity approximately about 20%, does not surpass the relative luminosity 40%. M. formosana could adaptate much different light environment, being suitable for planting at the gap which light intensity were between 40~60% full sunlight. M. azedarach having better plasticity of physiology and morphology, under the low light grows receives limits, being suitable for planting at the gap which light intensity were relative luminosity 40% to the full sunlight between.

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Shainsky, Lauri J. "Competitive interactions between Douglas-fir and red alder seedlings : growth analysis, resource use, and physiology /." 1988. http://hdl.handle.net/1957/11064.

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Lih, Xiao-Wen, and 酈學文. "The influence of water treatment on morphology, leaf physiology and photosynthesis of Sapindus mukorossi seedlings." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/39920670667871156719.

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碩士 國立臺灣大學 森林環境暨資源學研究所 102 From field observations, we found that Sapindus mukorossi has good performance in water deficit habitat. In order to understand the adaptation mechanism of S. mukorossi, we planted three-year-old seedlings under various water treatments and measured the responses on phenology, physiology and internal adjustment of the seedlings. In this study we applied three water treatments based on soil relative water content. The results indicate that S. mukorossi had the best performance under sufficient water supply, but can survive on dry soil, which represent permanent wilting point for some other plants (RWC 4.96%). There’s no obvious difference in the biomass allocation and leaf morphological response among treatment, except the leaf angle. S. mukorossi shows strong avoidance function to avoid the loss of body water, such as low stomatal conductance, high apoplastic water content in tissue, dense cytoplasm and low elasticity coefficient of cell wall, which can help S. mukorossi to survive in drought environment. S. mukorossi grown under sufficient water supply had the best photosynthetic performance and the lowest which under drought treatment. However, the result of the analysis of leaf plasma membrane and chlorophyll fluorescence show that there’s no damage of photosystem under water deficit condition and plant can maintain photosynthetic capacity in drought environment. High level protection of the photosystem might contribute to the maintenance of photosynthetic capacity during water deficit. However, high tolerance of drought stress of S. mukorossi could inhibit photosynthetic potential, thus, under sufficient water supply condition, it would not be beneficial to compete with other similiar lifestyle plants.

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LIN, XIU-CHENG, and 林秀澄. "Effects of iron on the physiology and mineral nutrition status of papaya (carica papaya L.) seedlings." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/51347363608761149850.

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Gleason, John F. "Fertilization of 2-0 ponderosa pine seedlings in the nursery and field : morphology, physiology, and field performance /." 1988. http://hdl.handle.net/1957/13585.

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Lomas, M. Christine. "Physiology and genetics of drought hardiness in coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) seedlings /." 1999. http://hdl.handle.net/1957/10928.

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LIM, LAN-WEE, and 林蘭妃. "Studies on Stress Physiology and Ethylene Biosynthesis in Snap an (Phaseolus vulgaris L.) Seedlings Treated with Cadmium Sulfate." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/28056110680189019735.

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碩士 國立中興大學 園藝學系 83 The general symptoms of snap bean seedlings treated with 0.2-2.0 ppm cadmium sulfate were leaf chlorosis, vein browning, pulvinus shrinkage, lost of nctinasty and leaf drop. Growth rate was also reduced together with reduced leaf size, degraded chlorophyll and increased peroxidase activity. Most cadmium absorbed was accumu- lated in the roots with some translocated to the shoots. The levels of Fe, Mn, Zn, Cu in the shoots decreased with elevated cadmium concentration. Normal snap bean hypocotyls produced very little ethylene, but following a cadmium ion stress, an abrupt and temporal pattern of stress ethylene production was induced after a lag period of 3 hours. CHI and AVG effectively inhibited stress ethylene produc- tion, suggesting that cadmium induced de novo synthesis of ACC synthase which, in turn, is the rate-controlling enzyme in the pathway of ethylene biosynthesis. Cadmium also inhibited EFE activity, guaiacol-peroxidase activity and tissue browning.

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Grissom, James Edwin. "Growth and physiology of loblolly pine (Pinus taeda l.) seedlings as affected by genetics of the root system." 2003. http://www.lib.ncsu.edu/theses/available/etd-05192003-161656/unrestricted/etd.pdf.

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Khan, Shafiqur Rehman. "Effects of water stress on phenology, physiology, and morphology of containerized Douglas-fir (Psuedotsuga menziesii (mirb.) Franco) seedlings /." 1992. http://hdl.handle.net/1957/10894.

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Dissertations / Theses on the topic 'Seedling physiology'

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