Academic literature on the topic 'Seedling Shoot'
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Journal articles on the topic "Seedling Shoot"
1
Ekamawanti, Hanna Artuti, Lenawati Simanjuntak, and Abdurrani Muin. "Assessment of the Physical Quality of Eucalyptus pellita Seedlings from Shoot Cutting by Age Level." Jurnal Sylva Lestari 9, no. 2 (2021): 280. http://dx.doi.org/10.23960/jsl29280-290.
Full textAbstract:
The criteria for target seedling of Eucalyptus pellita F. Muell are at least 90days old, with consequences for the length of stay of the seedlings in the nursery. This study must assess the suitability as a target seedling first if it wants to plant the seedlings under 90days old in the field. The research aimed to evaluate and obtain the regression equation for the seedling’s age with the seedling’s morphological characters. The shoot seedlings cuttings aged 45, 60, 75, and 90 days after planting in the cocopeat growing medium were assessed. The study was used a survey method with a purposive sampling technique to obtain 60 samples by assessing the growth and appearances of the seedling. Furthermore, 15 samples were taken at random to determine the dry weight of the seedlings. Seedlings aged 75 and 90 days indicated the standard criteria as target seedlings for height, diameter, number of leaves, seedling’s health, shoot appearances, and seedling roots. The two seedlings’age levels have a sturdiness index of 8.34-9.78; shoot-root ratio 3.9-4.5; and seedling quality index (SQI) 0.22-0.23. Seedling age had a powerful positive correlation with the sturdiness index and SQI (r = 0.84 and r = 0.96). The regression equation of the sturdiness index is y = 0.048x + 5.435 (R2 = 0.996) and SQI is y = 0.004x - 0.064 (R2 = 0.926). This research implies that 75 and 90-days seedlings can be considered as one of the criteria for the age of E. pellita shoot cuttings as the target seedling in the SOP of PT. Finnantara Intiga.Keywords: cocopeat, Eucalyptus pellita, Seedling Quality index, shoot cuttings, target seedling
2
Sucoff, Edward, Cindy Buschena, and Perry Tamte. "Desiccation and water potentials in the roots, leaves, and shoots of bare-root red pine and white spruce." Canadian Journal of Forest Research 15, no. 5 (1985): 989–92. http://dx.doi.org/10.1139/x85-157.
Full textAbstract:
Bare-root seedlings of red pine (Pinusresinosa Ait.) and white spruce (Piceaglauca (Moench) Voss) were dried in various controlled situations before measurement of water potential (ψ) and moisture contents. For each situation, root ψ was directly proportional to and highly correlated with shoot ψ. The regression lines did not vary with environment for fully exposed seedlings within a seedling lot. Regressions did differ between seedling lots and between seedlings that had roots only, shoots only, or both roots and shoots exposed. Since the differences between root and shoot ψ were sometimes large and roots are more likely to be damaged by a given level of desiccation during handling, we suggest that root ψ may be the preferred predictor of postplanting seedling behavior.
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Sykes, SR. "Effects of seedling age and size on chloride accumulation by juvenile citrus seedlings treated with sodium chloride under glasshouse conditions." Australian Journal of Experimental Agriculture 25, no. 4 (1985): 943. http://dx.doi.org/10.1071/ea9850943.
Full textAbstract:
Chloride accumulation by juvenile citrus seedlings treated with sodium chloride for 56 days, using either nutrient solution culture (50 mM NaCl) or pot culture (75 mM NaCl) techniques under glasshouse conditions, was investigated in relation to seedling age. Ranking of cultivars on the basis of leaf chloride concentrations varied according to the age of seedlings examined. Leaf chloride concentrations of 6-, 5-, 4- and 3-month-old seedlings of eight cultivars examined in solution culture decreased with seedling age and were negatively correlated with seedling dry weight within some cultivars. Cultivar differences in leaf chloride concentrations, which occurred for all age groups, were negatively correlated with shoot growth and seedling dry weight for 5-month-old seedlings only. Leaf chloride concentrations of seedlings treated with NaCl in pot culture also changed with the age of seedlings (5, 17- and 29-monthsold) and varied between cultivars, with significant cultivar x age interactions. The effect of seedling size on chloride accumulation was investigated using nutrient solution culture. Six-month-old seedlings of four varieties were treated with NaCl (50 mM) for 56 days. Two size classes were obtained by growing seedlings at two densities before salt treatment. Small seedlings had greater shoot chloride concentrations than equivalent large seedlings and cultivar ranking, based on shoot chloride concentrations, changed with seedling size. Cultivar differences in leaf chloride concentrations were negatively correlated with seedling growth and dry weight for small seedlings but not for large seedlings. Seedling size had no effect on root chloride concentrations. The results suggest that screening very small seedlings for chloride exclusion is not feasible since rankings based on leaf chloride concentrations did not agree with documented data for grafted trees. There appeared to be a critical or threshold seedling age or size at or above which rankings for shoot chloride accumulation by good chloride excluders were consistent with documented field data. The results are discussed in relation to screening citrus hybrids for chloride exclusion under glasshouse conditions.
4
Svenson, Sven E. "Shading and DCPTA Interactively Influence Shoot Growth of Hypoestes." HortScience 30, no. 4 (1995): 854D—854. http://dx.doi.org/10.21273/hortsci.30.4.854d.
Full textAbstract:
The objective of this study was to determine if shading and DCPTA application interactively influence seedling emergence and shoot growth of Hypoestes phyllostachya Bak. seedlings. Hypoestes `Carmine Red' seeds were soaked for 6 h in distilled water, and then soaked 6 h in solutions containing' 10 mg DCPTA/liter (30 mM) and 0.1% Tween-80, 0.1% Tween-80, or distilled water. Date of seedling emergence was recorded after sowing (0.5 cm) in 9-cm (460 ml) pots filled with 440 ml of a 5 pine bark: 4 Florida sedge peat: 1 sand medium. Forty pots from each of the three seed-soak treatments were grown under 30%, 63%, or 84% shading, provided by saran-type shadecloth, using natural photoperiods (completely randomized design). Shoot heights and dry weights were recorded 75 days after sowing. Neither shading nor DCPTA influenced total seedling emergence or seedling emergence rate (time to 50% emergence). Under 30% shading, seedlings from DCPTA-treated seeds were taller and had more shoot dry weight than seedlings from surfactant- or water-treated-seeds; however, DCPTA did not influence seedling height or shoot weight under 63% or 84% shading.
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Frisby, James W., and Schuyler D. Seeley. "CHILLING OF PEACH SEEDS, SEEDLINGS AND CUTTINGS." HortScience 25, no. 9 (1990): 1088f—1088. http://dx.doi.org/10.21273/hortsci.25.9.1088f.
Full textAbstract:
Correlations were made between the responses of seeds, physiologically dwarfed seedlings and dormant cuttings to similar chilling treatments. Seed germination correlated highly with growth of physiologically dwarfed seedlings and shoot growth of dormant cuttings. Emergence and seedling growth correlated poorly with germination, growth of physiologically dwarfed seedlings and shoot growth of dormant cuttings. Thus, germination was a better seed predictor of the mature peach chilling response than emergence or seedling growth. Growth of dwarfed seedlings correlated highly with shoot growth of dormant cuttings. The anomalous leaf condition of peach seedlings may have confounded seedling growth after seed chilling, but was not a problem when the chilling treatment was provided to physiologically dwarfed seedlings. The dormancy release mechanisms that promoted seed germination, growth of physiologically dwarfed seedlings and growth of dormant cuttings were similar.
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Marohnic, Jennifer, and Robert L. Geneve. "Container Volume and Height Affect Shoot and Root Development in Marigold Seedlings." HortScience 30, no. 4 (1995): 868B—868. http://dx.doi.org/10.21273/hortsci.30.4.868b.
Full textAbstract:
Marigold seedlings were grown in four containers that differed in both volume and shape. Seedlings grown in 1.5-gal containers showed the greatest potential for shoot and root development 20 days after sowing. These seedlings had greater leaf area, shoot and root dry weight, and total root number and length compared to seedlings grown in 406 plug trays, 72-cell packs, or 6-inch containers. There was a positive correlation (r2 = 0.81) between cell volume and seedling growth as well as a positive correlation (r2 = 0.89) between container height with seedling growth. An attempt was made to separate the impact of container volume vs. container height on seedling growth. Containers were designed using acrylics to vary the container height while keeping the volume constant at 1500 cm3. There was a positive correlation (r2 = 0.87) between shoot and root dry weight with container height. The data suggest that both container volume and height contribute to overall seedling growth in marigold, but when container volume is not limiting, container height has a large impact on seedling development.
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Frisby, James W., and Schuyler D. Seeley. "Chilling of Endodormant Peach Propagules: III. Budbreak and Subsequent Growth of Physiologically Dwarfed to Near Normal Seedlings." Journal of the American Society for Horticultural Science 118, no. 2 (1993): 258–62. http://dx.doi.org/10.21273/jashs.118.2.258.
Full textAbstract:
We studied the response of physiologically dwarfed (PD) to near normal peach [Prunus persica (L.) Batsch] seedlings (`Johnson Elberta' seeds) to various chilling treatments. Peach seedlings were obtained by forcing seeds that had been subjected to a brief stratification treatment. Seedlings were divided into four types (groups) according to the length of the primary stem and the presence and size of lateral branches. The seedlings were used in a chilling study with treatments of five durations (20 to 60 days) at four temperatures (2 to 14C). Terminal shoot growth and lateral budbreak were recorded 17 days after forcing. Shoot and leaf dry weight were obtained after seedlings had grown for 64 days. Budbreak and growth improved with the duration of the chilling treatment. Generally, 7C was the best chilling temperature, with 2 or 10C only slightly less effective. Treatment at 14C did not promote budbreak or growth. Budbreak and growth had significant interactions between treatment duration and temperature. The seedling type and treatment duration interaction was significant for terminal shoot length, lateral budbreak, and leaf dry weight, but were probably the result of differences between the seedling types before treatment and not true interactions with the length of the treatment. There was a significant interaction between the seedling type and treatment temperature on terminal shoot growth. Subsequent shoot growth did not differ significantly between the seedling types after similar chilling treatments. Thus, shoot growth was the best indicator of the chilling process of `Johnson Elberta' peach seedlings. Indicators of dormancy removal such as lateral budbreak or terminal shoot growth after 17 days forcing were not good predictors of subsequent seedling growth.
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Ren, Yun, Jianfang Zhu, Nazim Hussain, et al. "Seedling age and quality upon transplanting affect seed yield of canola (Brassica napus L.)." Canadian Journal of Plant Science 94, no. 8 (2014): 1461–69. http://dx.doi.org/10.4141/cjps-2014-021.
Full textAbstract:
Ren, Y., Zhu, J., Hussain, N., Ma, S., Ye, G., Zhang, D. and Hua, S. 2014. Seedling age and quality upon transplanting affect seed yield of canola (Brassica napus L.). Can. J. Plant Sci. 94: 1461–1469. Seedling quality is an essential indicator for seed yield in canola, which is affected by many factors, including seedling age. Two field experiments were conducted to compare canola seedling quality and seed yield on 30-, 35-, 40-, 45-, 50-, 55-, and 60-d-old seedlings in 2011 and 2012. The relationship between seedling quality traits and seed yield of different seedling ages was also analyzed. Results revealed that the highest seed yield obtained from 40-d-old seedlings was attributed to more branches and siliques per plant. The negative effect of young seedlings (30-d-old) on seed yield was greater than that of old seedlings (60-d-old). The reduction rates in seed yield on the 30- and 60-d-old seedlings were 25.7 and 18.2%, respectively, compared with the 40-d-old seedlings. Increased root neck diameter, green leaf number, shoot, and root dry matter was the case on 40-d-old seedling transplanted plants compared with other ages. However, the increase was larger in the old seedlings than in the young seedlings. On average, the shoot and root dry weights of the 30-d-old seedlings were 1.9 and 1.7% of those in the 60-d-old seedlings. However, correlation analysis revealed that the seedlings with the highest shoot and root dry matter did not necessarily obtain the highest seed yield. Factor analysis suggested that the effects of root neck diameter and green leaf number on seed yield were more pronounced than those of shoot and root dry matter. Therefore, high seed yield in canola could be defined in terms of optimum green leaf numbers and branches per plant.
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Livingston, N. J., and T. A. Black. "The growth and water use of three species of conifer seedlings planted on a high-elevation south-facing clearcut." Canadian Journal of Forest Research 18, no. 10 (1988): 1234–42. http://dx.doi.org/10.1139/x88-190.
Full textAbstract:
Container-grown 1-0 seedlings of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), and Pacific silver fir (Abiesamabilis (Dougl.) Forbes) were spring planted on a south-facing high-elevation clearcut located on Mount Arrowsmith, Vancouver Island, British Columbia, and their growth and development was measured over three successive growing seasons. Treatments designed to modify seedling microclimate, including provision of shade cards, irrigation, and irrigation and shade cards combined, had a marked effect on the extent and type of growth in all species. Irrigated seedlings had the largest shoot dry masses and the highest shoot to root dry mass ratios. Shaded seedlings had larger shoots than untreated seedlings, which had the lowest shoot to root dry mass ratios. All seedlings showed a pronounced decline in seasonal growth 1 year after planting. Douglas-fir seedlings exhibited a high degree of drought tolerance; in the driest year there was only a 20% difference in total dry matter production between irrigated and nonirrigated seedlings. Western hemlock and Pacific silver fir seedlings, despite not being drought tolerant, expended water to achieve growth and thereby exposed themselves to desiccation. Measurements of growing-season seedling dry matter production were better related to estimates of growing-season transpiration, obtained by summing the products of seedling leaf area, hourly D/(RvT′), where D is vapour pressure deficit, Rv is the gas constant for water vapour, and T′ is the absolute air temperature, and stomatal conductance derived from a boundary-line analysis model, than to estimates of growing-season average total seedling canopy conductance, i.e., the average of the products of seedling leaf area and stomatal conductance.
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Dufault, Robert J. "Relationship among Nitrogen, Phosphorus, and Potassium Fertility Regimes on Celery Transplant Growth." HortScience 20, no. 6 (1985): 1104–6. http://dx.doi.org/10.21273/hortsci.20.6.1104.
Full textAbstract:
Abstract ‘Utah 52-70R’ celery (Apium graveolens L.) seedlings were fertilized weekly with solutions containing N, P, and Κ to determine the nutrient needs required to produce high quality transplants. As Ν rate increased from 10 to 250 ppm, shoot number, seedling diameter and height, leaf area/seedling, shoot and root dry weight/seedling, and dry weight/shoot increased in 52-day-old seedlings. As P rate increased from 5 to 125 ppm, seedling diameter, height, shoot dry weight/shoot, and leaf area increased, but root dry weight and shoot number were not affected. Nitrogen interacted with P for all growth variables measured. Increasing P rates from 5 to 125 ppm significantly increased shoot number, diameter, height, and shoot and root dry weights only in combination with Ν rates of at least 250 ppm; however, dry weight/shoot, leaf area, and root to shoot dry weight ratios increased with P rates used in conjunction with at least 50 ppm N. Potassium rates from 10 to 250 ppm affected neither the growth variables nor did they interact with P or N. Therefore, to grow high-quality celery transplants, nutrient solutions should contain at least 250N–125P–10K (ppm) if a ver-miculite-peat-perlite medium low in N, P, and Κ is used.
Dissertations / Theses on the topic "Seedling Shoot"
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Spalholz, Hans. "Development of Short Term Storage Techniques for Grafted Vegetable Seedlings." Thesis, The University of Arizona, 2013. http://hdl.handle.net/10150/293734.
Full textAbstract:
Vegetable grafting confers soil-borne disease resistance through the use of selected rootstocks. Additional costs associated with grafted vegetable seedling propagation limit grower access to this technology. The use of low temperature storage in grafted seedling production reduces labor costs and allows propagators to meet the seasonal and narrow-window demand of growers. For the first part of the experiment 22 genotypes of Solanaceae or Cucurbitaceae seedlings were evaluated in low temperature storage conditions (5 or 12°C). Seedling performance was better in 12°C storage than in 5°C storage. For the second part of the experiment watermelon, the most low-temperature sensitive species found in our first study, was grafted onto two different commercial rootstocks or on to other watermelon seedlings and stored at 12°C for two and four weeks. Both 'Strong Tosa' and 'Emphasis' rootstocks conferred chilling tolerance during storage to watermelon scions, allowing storage of grafted plants for two weeks.
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Mwitwa, Jacob Pacific. "Growth and physiological parameters related to shoot dieback in Pterocarpus angolensis DC seedlings." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/20431.
Full textAbstract:
Thesis (PhD)--Stellenbosch University, 2004.<br>ENGLISH ABSTRACT:Six experiments, five in the glasshouse and one in the field near Nelspruit, were
carried out to ascertain the effect of factors related to shoot die-back, and of water
treatments on the growth and physiological responses of Pterocarpus angolensis
seedlings. The study was undertaken to broaden the knowledge and understanding of
the phenomenon of shoot die-back in order to enhance our ability to regenerate the
species. The following experiments were carried out
(a) Assessment of biomass accumulation; anatomical characteristics of the shoot
apical meristem; foliar, stem and root concentration of micro- and macronutrients
associated with each phenophase,
(b) Effect of seedling age and seed source on the occurrence of shoot die-back
under field conditions;
(c) Water treatment effects on ChI. afluorescence traits of£'. angolensis seedlings
obtained by assessing the fluorescence yield of photosynthetic samples
subjected to dark- and light-adaptation;
(d) Genetic variation in shoot die-back and other traits of sixteen halfsib families
of £.. angolensis from Malawi, Namibia and Zambia grown over two die-back
seasons.
Experiments conducted revealed the following
1. Patterns of growth observed in phenophases are indicators of seasonal changes in
annual biomass allocation to the shoot and root. Phenophases such as leaf loss
and stem senescence, whether shoot die-back occurs completely or not, are
directly related to the decline in above-ground biomass and declined rate of
increase in root biomass respectively. Leaf flush, expansion and maturation result
in increased biomass accumulation whilst shoot die-back has a minimal downregulatory
effect on root biomass accumulation compared to the shoot. Shoot dieback
is not sudden, therefore from the first day of germination, seedlings
synchronise growth and development with the occurrence of shoot die-back.
2. Phenophasic concentration of foliar N, Ca and Mg, stem Fe and Cu and root
concentrations of P, K, Mg, Fe and B are associated with shoot die-back. Patterns
of mineral nutrient concentration obtained in foliage and roots but to a lesser
extent in the stem, may be related to nutrient remobilisation during shoot dieback.
Higher relative mineral nutrient changes during leaf yellowing and shoot
die-back may be an indication of the removal of significant volumes of mobile
nutrients from senescing tissues.
3. The volume of the shoot apex of E. angolensis remains constant during different
phenophases which points to seasonal uniformity in the size of the apical dome.
Changes in phenology associated with declined growth, or shoot die-back, is
revealed through declined cell number in the tunica which is a reflection of
declined mitotic activity.
4. Shoot die-back occurs in all seedlings from nursery stock planted under field
conditions and all seedlings of up to two years experience complete shoot dieback.
Shoot die-back takes place irrespective of seed source or the age of nursery
stock that is planted. Survival after the first shoot die-back is normally low. Water
treatments had no significant effect on the function of PSIJ reaction centres of P.
angolensis nursery seedlings. In the case of both dark- and light-adapted leaves,
water treatment had no significant effect on the measured Chi. a fluorescence
parameters or the calculated parameters (specific activities, phenomenological
fluxes, structure-function and performance indexes and drivingforces).
5. Water treatments affect the shape of ChI. a fluorescence transients of lightadapted
compared to that of dark-adapted photosynthetic samples of E.
angolensis. No significant water treatment effect was obtained for extracted and
technical Chi. afluorescence parameters, specific fluxes, quantum efficiencies and
phenomenological fluxes. Quantum yield, relative electron transport and quantum
yield limitation, de-excitation rate constants, structure-function, performance
indexes and driving forces were also not significantly different across water
treatments.6. Genetic variation was observed to exist among 16 halfsib families from Malawi,
Namibia and Zambia. High heritabilities were obtained for shoot die-back and
other traits, indicating that shoot die-back is genetically controlled. The trait is
passed from parents to offspring and it is highly probable that it occurs,
throughout its natural range, in all seedlings. Since shoot die-back is genetically
programmed, it remains crucial to the ability of a seedling to regenerate in the
following rainy season<br>AFRIKAANSE OPSOMMING:Ses eksperimente, vyf in die glashuis en een in die veld naby Nelspruit, is uitgevoer
om die effek van faktore wat verwant is aan die terugsterwing van lote op saailinge,
sowel as om die effek van waterstres op die groei en fisiologiese responsies van
Pterocarpus angolensis saailinge, te ondersoek. Die studie is ondemeem om die
kennis en begrip aangaande die regenerasie-dinamika van die spesies te verbeter. Die
volgende eksperimente is uitgevoer:
(a) Evaluering van die effek van jisiologiese veranderings op biomassa; blaar-,
stam- en wortelkonsentrasies van spoor- en makro-voedingselemente, en
anatomiese eienskappe van die apikale meristeem van die lote.
(b) Effek van saailingouderdom en saadbron op die voorkoms van lootterugsterwing
onder veldtoestande.
(c) Waterbehandelingseffekte op Chi. ajluorisensie eienskappe van ,e. angolensis
saailinge wat verkry is deur die jluorisensie te evalueer van fotosintesemonsters
wat aan donker- en lig-adaptasies onderwerp is.
(d) Genetiese variasie in loot-terugsterwing en ander groei-eienskappe van 16
halfsib families van ,e. angolensis vanaf Malawi, Namibia en Zambia wat
gekweek is oor twee terugsterj-seisoene.
Die eksperimente het die volgende aan die lig gebring:
1. Groeipatrone waargeneem gedurende die fenofases is indikatore van seisoenale
veranderings in jaarlikse biomassa allokasies aan die loot en die wortels.
Fenofases soos blaarverlies en lootafsterwing, ongeag of loot-terugsterwing
volledig is of nie, is direk verwant aan die afname in bogrondse biomassa en
afnemende tempo van toename in wortelbiomassa respektiewelik. Bottende blare,
vergroting en rypwording van blare lei tot toenemende biomassa akkumulasie
terwyl loot-terugsterwing 'n minimale afskalende effek op akkumulasie van
wortelbiomassa het in vergelyking met die van die loot. Loot-terugsterwing is nie
skielik, met ander woorde vanaf die eerste dag van ontkieming sinchroniseer
saailinge groei en ontwikkeling met die voorkoms van loot-terugsterwing.
2. Fenofase konsentrasies van en veranderings in blaar N en Ca en loot Fe, asook
veranderings in waargenome wortel N, K, Ca, Mn, Cu, Zn en B is sterk geassosieer
met loot-terugsterwing. Patrone van minerale
voedingselementkonsentrasies wat in blare en wortels, en in minder mate in die
loot, verkry is, mag direk verwant wees aan hermobilisering van
voedingselemente gedurende loot-terugsterwing. Hoe relatiewe minerale
voedingselementveranderings gedurende die vergeling van blare en lootterugsterwing
mag 'n indikasie wees van die verwydering van betekenisvoUe
hoeveelhede mobiele nutriente vanaf sterwende weefsel.
3. Die volume van die groeipunt van r. angolensis bly konstant gedurende
verskillende fenofases wat dui op seisoenale uniformiteit in die grootte van die
apikale koepel. Veranderings in fenologie ge-assosieer met afnemende groei, of
loot-terugsterwing, word gerejlekteer deur afnemende selgetaUe in die tunika wat
dui op afnemende mitotiese aktiwiteit.
4. VoUedige loot-terugsterwing kom voor in aUe saailinge vanaf die kwekery wat in
die veld geplant word tot op die ouderdom van twee iaar. Dit kom voor angeag
van saadbron of ouderdom van saailinge ten tye van planting. Oorlewing na
aanvanklike loot-terugsterwing is normaalweg laag.
5. Water behandelings het geen beduidende effek op die funksie van PSII
reaksiesentra van r. angolensis kewekery-saailinge gehad. Vir beide donker- en
lig-aangepaste blare is geen beduidende waterbehandelingseffek verkry vir
waargenome ChI. a jluoresensie parameters of die berekende parameters
(spes ifieke aktiwiteite, jenomenologiese jlukse, struktuur-funksie-indekse,
"perjormance-indekse oj" driving forces" ).
6. Genetiese variasie tussen 16 halfsibfamilies vanaf Malawi, Namibie en Zambie is
verkry vir loot-terugsterwing en ander groei-eienskappe. Dit dui op genetiese
beheer van terugsterwing en dat die eienskap oorerjbaar is, en waarskynlik in die
hele natuurlike verspreidingsgebied van die spesies in aUe saailinge voorkom.
Aangesien loot-terugsterwing gene ties geprogrammeer is, is dit noodsaaklik vir
die vermoe van die plant om in die volgende reenseisoen te regenereer.
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Cohen, Susan Alese. "Regenerating Longleaf Pine on Hydric Soils - Short-Term Effects on Soil Properties and Seedling Establishment." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-04282008-191226/.
Full textAbstract:
Restoring longleaf pine ecosystems is essential for managing rare plant and animal species and protecting biological diversity in the southeastern Coastal Plain of the United States. Natural longleaf pine ecosystems range from xeric uplands to poorly-drained flatwoods and savannas. Most existing stands, however, occur on xeric to dry-mesic sites and approaches to restoring longleaf pine to wetter sites traditionally utilize intensive practices. There is little information available on the efficacy of these practices to establish longleaf pine seedlings on poorly-drained sites and their impacts on soil properties, seedling survival and growth, and the understory plant community. A research project was established at Marine Corps Base Camp Lejeune, NC to evaluate the effects of site preparation methods for returning longleaf pine on hydric soils with no natural seed source. Various site preparation treatments were evaluated in a field experiment, and results revealed greater growth and earlier emergence from the grass stage with more intensive site preparation. There was a marginal increase in soil nutrients, and a slight increase in foliar nutrients found with the more intensive treatments. Site preparation influenced seedling growth in the short-term and this was likely due to the cumulative effects of controlling competition and modifying the planting site. Marine Corps Base Camp Lejeune and other Department of Defense installations include both former and remnant longleaf pine ecosystems that support federally protected plants and animals such as the red-cockaded woodpecker - and thus face the challenge of restoring former, poorly-drained longleaf pine ecosystems. A land use history revealed that, largely due to its poorly-drained status and inaccessibility, the majority of disturbance on the research area occurred after the 1920âs and was largely due to forestry activities. Since purchasing the land area of the project in 1996, the Marine Corpsâ challenge has been to balance the mission of training and readiness with the need for restoration and long-term management of longleaf pine ecosystems. The results of this work provide natural resource managers with a scientific foundation for assessing choices to assist in this restoration and management effort.
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Langanke, Kristen L. "Response to Nitrogen and Salinity conditions in Rhizophora mangle Seedlings Varies by Site of Origin." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/7048.
Full textAbstract:
Many coastal plant species thrive across a range of environmental conditions, often displaying dramatic phenotypic variation in response to environmental variation. We characterized the response of the critical foundation species Rhizophora mangle L. to full factorial combinations of salt and nitrogen (N). We used seedlings collected from five populations and measured traits related to salt tolerance and N amendment. The response to increasing salt included significant plasticity in succulence, leaf mass area (LMA), and root to shoot ratio (R:S). Seedlings also showed overall reduced maximum photosynthetic rate in response to N amendment, but this response depended on the level of salt and varied by site of origin of the seedlings. Seedlings from different sites also differed in height growth, LMA, R:S, and total dry biomass. Generally, survival was lower in high salt and high N, but the impact varied among sites. Overall, this study revealed significant trait plasticity in response to salt and N level, and differentiation of responses of seedlings among different sites. Seedling survival depended on maternal family for 3 of 5 sites showing variation within and among sites. Variation in trait plasticity and seedling survival in R. mangle may be important for future adaptation to a complex mosaic of environmental conditions.
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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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Carter, Paul Quinton. "Effects of defoliation, debudding, and shoot pruning on growth, foliar carbohydrate level, and net photosynthetic rate in balsam fir, Abies balsamea, seedlings." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ35482.pdf.
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BassiriRad, Hormoz. "Influence of temperature on root water and ion transport and the subsequent effect on shoot water status and growth of barley and sorghum seedlings." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185129.
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Short term root temperature treatments between 15 to 40°C at a constant air temperature produced a differential response in shoot growth of barley and sorghum seedlings. Maximum growth rate occurred at 25°C in barley and 35°C in sorghum. The stimulation of growth in barley in the suboptimal temperature ranges (15 to 25°C) was associated with both enhanced L(p) and Jᵢ whereas growth inhibition at elevated temperatures (>25°C) was associated with no changes in L(p), but was accompanied by a severe inhibition of solute fluxes suggesting that supraoptimal temperature inhibition of growth in barley is caused by limited ion and not water supply to the leaves. In sorghum, the enhanced shoot growth in the 15 to 25°C range coincided with stimulated L(p) and Jᵢ. Between 25 to 35° temperature induced enhancement of growth was mainly caused by enhanced L(p). In both plants even when root L(p) appeared to cause temperature induced changes in growth, the bulk leaf water, osmotic and turgor potential remained unaffected. It is suggested that when reduced water supply limits growth, undetectable changes in xylem water potential may mediate temperature response in root L(p) and growth. Temperature effects on ion transport across the root were found to be regulated at the site of ion release into the xylem (Φ(cx)) rather than the site of ion entry into the root (Φ(oc)). When ABA was added to the external solution, L(p) was enhanced but qualitative responses of Jᵢ and L(p) to changes in root temperature remained unchanged in barley. However, addition of ABA to the medium with sorghum roots caused a severe inhibition of solute fluxes at temperatures above 25°C which happened only when the temperature was raised above 35°C in the absence of ABA. The ABA study suggested that temperature induced changes in root transport properties of both plants were not mediated by ABA.
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Yeh, Meei-Jyuan, and 葉美娟. "The Production and Improvment of Papaya Seedling from in vitro Shoot Cutting Propagation." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/81683388937064135596.
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Chen, Kuan-Chuan, and 陳冠全. "QTL mapping for root traits and shoot photosynthesis under salinity stress in rice seedling." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/39258625869248865994.
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碩士<br>國立臺灣大學<br>農藝學研究所<br>104<br>To increase the yield production, the crops may have to grow in the harsh environment. Salinity is one of the major abiotic stresses, and rice is very sensitive to increasing salts. In this study, we evaluated three different root types performance in South East Asia rice varieties, total sixteen loci were detected using genome-wide association mapping (GWAS), and two were found in previous study. In addition, chlorophyll fluorescence was used to measure the leaf photosynthesis rate under salt stress. The pilot experiment showed the effective PSII quantum yield (ΦPSII) on day 9 and Injury score (IS) on day 11 was moderately correlated (r = -0.588), suggesting the damage level of leaf photosynthesis rate and its repairing mechanism may be crucial for salinity tolerance in rice. Total 32 significant loci were detected by GWAS in five chlorophyll fluorescence related traits. Among these loci, two genes OsNHX3 and OsCBL4 related to salinity tolerance mechanisms were detected in the candidate regions. Finally, we analyzed root and shoot traits in diverse accessions and found that performance of shoot and root is independent under salt stress We expect these varieties could be used to improve salt tolerance through QTLs pyramiding approach in rice breeding program.
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Chen, Cheng-Hung, and 陳政宏. "Characterization of Soluble Invertase from Etiolated Seedling Shoots of Rice (Oryza Sativa)." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/80758976320224868047.
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碩士<br>國立臺灣大學<br>農業化學系<br>81<br>Two different forms of soluble invertases (IT I and IT II) were
extracted from etiolated seedling shoots of rice (Oryza
sativa), which could easily be separated by anion exchange
chromatography on DEAE-Sephacel column. Both enzymes are
glycoproteins with the abilities to hydrolyze sucrose and
raffinose but not maltose, therefore, they were .beta.-
fructofuranosidases (EC 3.2.1.26). The Km values for sucrose
and raffinose are 0.82 mM and 3.5 mM for IT I, and 10.2 mM and
10.56 mM for IT II, respectively. The optimum pH of the IT I is
slightly more acidic (4.5) than that of IT II (5.0). The
activity of two invertase isoforms was inhibited by fructose to
a different extent, but activated by bovine serum albumin. Both
enzymes were equally susceptible to incubation temperature
between 0 and 65℃. The sucrose hydrolyzing activity of both
enzymes was inhibited by iodoacetamide, pyridoxine, pyridoxal
and aniline, which may indicate that cysteine, basic and acidic
amino acid residues are important for the catalytic activity.
Books on the topic "Seedling Shoot"
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O'Reilly, Conor J. Bud and shoot development in different seedling types of western hemlock during nursery growth. Forestry Canada, 1989.
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Templeton, C. W. Effect of short-term storage of shoot tips from black spruce container seedlings on the estimation of bud initiation and needle primordia number. Ontario, Ministry of Natural Resources, 1992.
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Canada, National Research Council of. Second-Year Shoot Development in Black Spruce Picea Mariana (Mill.) B.S.P. Container Seedlings. s.n, 1986.
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Krasowski, Marek J. Growth of short-day treated spruce seedlings planted throughout British Columbia. Forestry Canada [i.e. Canadian Forest Service], 1993.
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Krasowski, Marek J. Effect of nursery short day and drought treatments on development and early farm-field performance of western redcedar. Canada/BC Economic & Regional Development Agreement, 1990.
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Parker, W. H. Seed zone delineation for jack pine in the former northwest region of Ontario using short-term testing and geographic information systems. Great Lakes Forestry Centre, 1996.
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Parker, W. H. Seed zone delineation for jack pine in the former northwest region of Ontario using short-term testing and geographic information systems. Great Lakes Forestry Centre, 1996.
Find full textBook chapters on the topic "Seedling Shoot"
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Satterlee, James W., and Michael J. Scanlon. "Protoplast Isolation from Undifferentiated Maize Seedling Shoot Tissue." In Methods in Molecular Biology. Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2164-6_9.
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Shimizu, Hiroshi, and Royal D. Heins. "Estimating Cuticle Resistance of Seedling Shoot Tips Based on the Penman-Monteith Model." In Transplant Production in the 21st Century. Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-015-9371-7_8.
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Das, Priyanka, Rajeev N. Bahuguna, Rohit Joshi, Sneh Lata Singla-Pareek, and Ashwani Pareek. "In search of mutants for gene discovery and functional genomics for multiple stress tolerance in rice." In Mutation breeding, genetic diversity and crop adaptation to climate change. CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0045.
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Abstract Mutation breeding is a commanding tool, which has been adapted to generate altered genetic material to study functional genomics, including understanding the molecular basis of stress tolerance. Hitherto, several rice lines have been generated through mutagenesis and the mutated genes responsible for the 'gain of function' in terms of plant architecture, stress tolerance, disease resistance and grain quality have been characterized. Oryza sativa L. cv. IR64 is a high-yielding rice cultivar but sensitive to abiotic stresses such as acute temperatures, salinity and drought. In this study, a population of rice IR64 mutants was generated using gamma irradiation. The population was then subjected to a preliminary phenotypic screening under abiotic stresses such as heat and salinity at the seedling stage. On the basis of root length, shoot length, fresh weight, dry weight and chlorophyll measurements, we identified eight 'gain-of-function' mutant lines and used them for further biochemical and molecular characterization. Phenotyping results demonstrated that the identified mutant plants have gained the potential to thrive under heat and salinity conditions. This information would be of wide scientific interest and helpful for developing novel cultivars able to maintain yield in saline, hot and dry areas.
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Lantican, Gaudencia A. "Field Screening of Gamma-Irradiated Cavendish Bananas." In Efficient Screening Techniques to Identify Mutants with TR4 Resistance in Banana. Springer Berlin Heidelberg, 2022. http://dx.doi.org/10.1007/978-3-662-64915-2_7.
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AbstractIn our search for Cavendish bananas to withstand Fusarium oxysporum f. sp. cubense (Foc TR4) and other diseases, field screening of tissue-cultured Grand Nain banana seedlings derived from gamma-irradiated shoot tips was explored. Six months after irradiation and multiplication in the laboratory, the plantlets (M1V6) were individually grown in seedling bags under screen house conditions for 8 weeks, side-by-side with non-irradiated plantlets of the same clone. Once acclimatized, the banana plants were grown in an area confirmed positive of Foc TR4 (based on previous farm records stating that more than 50% of the plant population succumbed to the disease). Seedlings from each treatment (dose of radiation) were divided into four replicates, regardless of the number of plants. Each plant was given a unique identification code for traceability during disease monitoring, bunch and fruit quality evaluation.Incidences of Foc TR4, Moko disease (Ralstonia solanacearum) and virus diseases were monitored weekly. Plants found positive of any disease were eradicated immediately. The plant population for the succeeding generation was managed by removing the unwanted suckers, 12 weeks from planting using a spade gouge and keeping only one sucker per plant for the next generation. Agronomic characters of each plant were taken at the flowering stage. These included age to flower, height, pseudostem circumference, number of leaves and height of the sucker. The bunch was harvested 12 weeks from flowering. The number of hands in a bunch, the number of fingers and weight of a hand were recorded. The same agronomic characters of the plant were taken for the succeeding generations.Plants left standing in the field without any disease symptoms 3 years after planting were considered as putative mutants and were selected as candidate lines for multiplication and second-generation field screening. Only healthy suckers (free from viruses) were further multiplied via tissue culture technique to reach M1V6. Clean suckers from each line free of soil debris or dirt were sent to the laboratory for multiplication. At least 1000 plantlets were produced from each line for the second-generation field screening. These were grown in two locations – with and without records of Foc TR4. Field monitoring activities including plant population management, disease incidence assessment and fruit quality evaluation were carried out following the same protocols used in the establishment of the first-generation plants. Lines with population showing ≤10% Foc TR4 after the first harvest, with good vigor, fruit quality and productivity were considered as candidates for further multiplication, farmers distribution and field planting under semi-commercial scale.
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Kasperbauer, M. J., and P. G. Hunt. "Shoot/root assimilate allocation and nodulation of Vigna unguiculata seedlings as influenced by shoot light environment." In Symbiotic Nitrogen Fixation. Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-1088-4_10.
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Ericsson, Tom. "Growth and shoot: root ratio of seedlings in relation to nutrient availability." In Nutrient Uptake and Cycling in Forest Ecosystems. Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0455-5_23.
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Bigras, Francine J., Aija Ryyppö, Anders Lindström, and Eva Stattin. "Cold Acclimation and Deacclimation of Shoots and Roots of Conifer Seedlings." In Tree Physiology. Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-015-9650-3_3.
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Cooper, H. D., D. T. Clarkson, M. G. Johnston, J. N. Whiteway, and B. C. Loughman. "Cycling of amino-nitrogen between shoots and roots in wheat seedlings." In Fundamental, Ecological and Agricultural Aspects of Nitrogen Metabolism in Higher Plants. Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4356-8_11.
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Koike, T., M. Kitao, A. M. Quoreshi, and Y. Matsuura. "Growth characteristics of root-shoot relations of three birch seedlings raised under different water regimes." In Roots: The Dynamic Interface between Plants and the Earth. Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-2923-9_29.
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Volkaert, H. "Influence of Explant Source on in Vitro Axillary Shoot Formation in Oak (Quercus robur L.) Seedlings." In Plant Aging. Springer US, 1990. http://dx.doi.org/10.1007/978-1-4684-5760-5_45.
Full textConference papers on the topic "Seedling Shoot"
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Torkaman, Javad, and Tooba Abedi. "Investigating the Amount of Carbon Sequestration of Oak Seedling (Quercus castaneifolia C. A. Mey.)." In 3rd International Congress on Engineering and Life Science. Prensip Publishing, 2023. http://dx.doi.org/10.61326/icelis.2023.4.
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One of the most important ways to reduce Atmospheric carbon is the carbon sequestration by trees. In this study, by using some morphological characteristics of the root and stem of Oak seedling the carbon sequestration evaluated. For this purpose, one hundred seedlings were sampled by method of Systematic-Random from the planting bed on March 2022 in the Pylambra nursery at Guilan province. Seedlings are divided to three grades small, medium and large according to Root Collar Diameter (RCD). The biomass and carbon sequestration of Oak seedling calculated according to the basic density of its root and stem. the Pearson's correlation coefficient used for correlation detection between variables. The one-way analysis variance test at the 95% confidence level used to recognize difference between biomass and carbon sequestration of three group of the Oak seedlings. The results of correlation analysis showed that the root collar diameter (RCD) had the strongest correlation with other morphological characteristics. the amount of the basic density for the root and shoot of the Oak seedling obtained about 0.57 gr/cm3 which is the same for both of them. the amount of the biomass and carbon sequestration of the root obtained more than shoot at the small and medium seedlings, whereas in large seedling was the same. In general, by increasing the size of seedling the biomass and carbon sequestration increased.
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Momčilović, Jovana, Dragana Jakovljević, Milica Kanjevac, and Biljana Bojović. "FIZIOLOŠKE KARAKTERISTIKE RASTENJA PŠENICE (Triticum aestivum L.) U USLOVIMA IN VITRO." In XXVII savetovanje o biotehnologiji. University of Kragujevac, Faculty of Agronomy, 2022. http://dx.doi.org/10.46793/sbt27.503m.
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This study aimed to examine the effect of different media - Murashige Skoog (MS) and Gamborg (B5) on the growth and development of in vitro seedling cultures of wheat (Triticum aestivum L.). The effects were evaluated through the measurement of root and shoot length, fresh and dry mass, as well as through the determination of the concentration of photosynthetic pigments (chlorophyll a, chlorophyll b, and carotenoids). The obtained data indicate that MS has better effects on the growth and development of wheat seedlings, since longer shoot length, and better fresh weight were observed on seedlings from this type of media. Additionally, higher chlorophyll b concentration and lower carotenoid concentration were measured in wheat leaves grown on MS medium. It can be concluded that MS is more suitable for establishing the initial in vitro culture of wheat compared to the B5 medium.
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Luković, Kristina, Nenad Đurić, Ivan Tupajić, et al. "ARTIFICIAL LIGHTING AS AN EFFECTIVE METHOD FOR INCREASING LETTUCE SEEDLING DEVELOPMENT." In 3rd International Symposium on Biotechnology. University of Kragujevac, Faculty of Agronomy in Čačak, 2025. https://doi.org/10.46793/sbt30.14kl.
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Due to the short duration of sunlight and low light intensity during the winter, the lettuce photosynthesis is limited, resulting in slow growth and reduced quality. This study aimed to investigate the effects of light- emmiting diodes (LEDs) on the growth and quality of three lettuce cultivar seedlings. Results of our research indicate that applied light treatments significantly influenced the growth and development of all three lettuce cultivar seedlings. The highest shoot and root weight was achieved in the Jukebox cultivar grown under blue LEDs, while the highest total chlorophyll and carotenoid content was achieved in the Viola cultivar grown under white and blue LEDs, respectively.
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Luković, Kristina, Aleksandra Rakonjac, Vladimir Perišić, Kristina Markeljić, and Slađan Adžić. "THE INFLUENCE OF ARTIFICIAL ILLUMINATION AND TILLAGE TREATMENTS ON ENHANCING LETTUCE GROWTH AND QUALITY." In 3rd International Symposium on Biotechnology. University of Kragujevac, Faculty of Agronomy in Čačak, 2025. https://doi.org/10.46793/sbt30.16kl.
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Lettuce (Lactuca sativa L.) indoor cultivation during the winter is mainly influenced by low light intensities. Also, its production is significantly affected by tillage techniques. Therefore, our research aimed to investigate the impact of applied light treatments during the seedling stage and applied tillage treatments after plant transplanting on the Viola lettuce genotype. Applied light and tillage treatments significantly influenced shoot weight, while the root weight and the total chlorophyll content varied depending on the light treatment. Tillage treatment did not affect shoot weight and the total chlorophyll content, but significantly influenced soluble sugar content.
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Hamid Ahmed, Maysaa, and Asmaa Obaid Ismeel. "Using Silver Nanoparticles to Increase Some Glycosidic Compounds of Stevia Rebaudiana in Vitro." In X INTERNATIONAL CONGRESS OF PURE AND APPLIED TECHNOLOGICAL SCIENCES. Rimar Academy, 2023. http://dx.doi.org/10.47832/minarcongress10-7.
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This experiment was objected to increase some Glycosides active compounds production in Stevia rebaudiana seedlings through plant seeds treatment with different concentrations of silver nanoparticles that diagnosed and characterized using AFM technique. This research was implemented at plant tissue culture laboratory of College of biotechnology - Al Nahrain University, throughout the period of 2022 and 2023. The experiment designed factorial within CRD using three expermentse and ten replicates. Sodium hypochlorite concentration (S1, S2, S3, S4) (0.0, 1, 2, 3%) represented the first experment, treatment duration time (T1, T2, T3) (5, 10, 15min) represented experiment 2, silver nanoparticles concentrations (C1, C2, C3, C4) (0, 10, 20, 30 mg.l-1) in MS media, represented experiment 3. Results showed that the contamination rate of the selected S. rebaudiana explant reduced and registered at at 10 and 15min in 3% sodium hypochlorite. The results also showed that there were a significant increase in the shoots numbers in 30 mg.l-1 AgNPs that reach the highest in terms of shoots numbers, the significant increasing of shoot length within the10 mg.l-1 enrolment 14.5cm then decreased in both concentrations 20, 30 mg.l-1 , seedlings dry weight significantly raised up to 20 mg.l-1 , while the seedlings dry weight also significantly droped in 30 mg.l-1 AgNPs., all the analyzed Glycosides compounds using HPLC device as Rubsoside , Dulcoside ,Stevioside concentrations were significantly increased in 20 and 30 mg.l-1 AgNPs, in comparsion to the control
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Gavrilova, Olga, and K. Pak. "INTENSIVE METHODS OF GROWING SEEDLINGS IN THE REPUBLIC OF KARELIA." In Biotechnologies in innovative afforestation and reforestation, monitoring of forest and forest reclamation systems. FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov, 2024. https://doi.org/10.58168/biarmffrs2024_53-58.
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The article discusses the prospects for using seedlings with a closed root system in the taiga zone, where, due to the short growing season, it is necessary to grow standard seedlings in greenhouse conditions. The seedlings were grown at different times and in cassettes of different volumes in a private nursery in Karelia with automatic sowing. Morphometric and weight indicators of seedlings were carried out, and it was noted that the timing of sowing affected them to a greater extent than the volume of the cassettes. It is noted that compliance with fertilizing technology, hardening and watering regimes ensured the production of standard pine seedlings during one-year cultivation. It is recommended to start the second rotation 1-2 weeks earlier for further growing of seedlings.
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Wang, Dongxue, Rajamohan Parthasarathy, and Xian Pan. "Advancing Image Recognition: Towards Lightweight Few-shot Learning Model for Maize Seedling Detection." In ICSCIS 2024: 2024 International Conference on Smart City and Information System. ACM, 2024. http://dx.doi.org/10.1145/3685088.3685198.
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Nozdracheva, R., and R. Kostennikov. "PECULIARITIES OF CHERRY PROPAGATION ON CLONAL ROOTSTOCKS." In FORESTRY-BIOLOGICAL FOUNDATIONS OF SUSTAINABILITY OF NATURAL AND ARTIFICIAL PHYTOCOENOSES. FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov, 2024. http://dx.doi.org/10.58168/fbfsnap2024_242-248.
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Cherry is a fruit stone fruit crop, popular in many countries of the world and on the territory of the Russian Federation. Cherry fruits are valued for their dessert and delicate taste, high content of nutrients. It is consumed fresh and processed. Cherries are especially suitable for making compotes. Breeders have created many varieties of cherries for different soil and climatic conditions. Cherry varieties differ in color and ripening of fruits. The trees are tall, have a spreading and sparse crown, and require regular pruning. To create cherry varieties with small-sized crowns, it is necessary to select compact crowns and propagate cherry varieties on clonal rootstocks. Scientific studies on the propagation of cherries on vegetatively propagated rootstocks indicate a decrease in the growth activity of annual seedlings in the fruit nursery, and shortening of the central trunk of seedlings (tweezing) allows you to increase the formation of side shoots at a given height and form a crown in annual cherry seedlings. It has been established that the studied cherry varieties when grafted on clonal rootstocks VSL-1 and LC-52 provide good survival in the nursery, high yield of planting material, but the growth and development of seedlings depends on variety-rootstock combinations.
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Merkel, K. A., and E. P. Vibe. "THE PREVALENCE OF INFECTIOUS LODGING OF SEEDLINGS OF COMMON PINE IN AUTUMN SOWING AT THE NURSERY OF SFNR" ERTIS ORMANY»." In STATE AND DEVELOPMENT PROSPECTS OF AGRIBUSINESS Volume 2. DSTU-Print, 2020. http://dx.doi.org/10.23947/interagro.2020.2.38-40.
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Phytopathological studies of the state of shoots of common pine (Pinus sylvestris L.) of autumn sowing when grown in protected soil with the use of Agrotex covering material were carried out. The results of survey showed that when using fertilizers and soil activators-nitrogen, phosphorus, boric acid, EM EKO KZ Soil, EM EKO KZ soil (NPK) and humus, there is a drop in seedlings from 7.5 to 32.6%. The main reason for the death of shoots was the development and spread of infectious pathogens of seedlings. The species composition of pathogenic microflora in diseased plants is represented by a group of soil fungi belonging to the anamorphic division-Fusarium, Alternaria. Evaluation of the experience of introducing substances into the soil during autumn sowing showed that their use, as a rule, does not affect the resistance of plants to infectious pathogens, with the exception of boric acid, which has fungicidal activity.
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Alli, Smaran, and Sabur Baidya. "Data-Augmented Few-Shot Object Detection for Efficient Identification of Invasive Weed Seedlings." In 2023 IEEE International Conference on Advances in Data-Driven Analytics And Intelligent Systems (ADACIS). IEEE, 2023. http://dx.doi.org/10.1109/adacis59737.2023.10424268.
Full textReports on the topic "Seedling Shoot"
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Flaishman, Moshe, Herb Aldwinckle, Shulamit Manulis, and Mickael Malnoy. Efficient screening of antibacterial genes by juvenile phase free technology for developing resistance to fire blight in pear and apple trees. United States Department of Agriculture, 2008. http://dx.doi.org/10.32747/2008.7613881.bard.
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Objectives: The original objectives of this project were to: Produce juvenile-free pear and apple plants and examine their sensitivity to E. amylovora; Design novel vectors, for antibacterial proteins and promoters expression, combined with the antisense TFL1 gene, and transformation of Spadona pear in Israel and Galaxy apple in USA. The original objectives were revised from the development of novel vectors with antibacterial proteins combined with the TFL-1 due to the inefficiency of alternative markes initially evaluated in pear, phoshomannose-isomerase and 2-deoxyglucose-6-phosphate phosphatase and the lack of development of double selection system. The objectives of project were revised to focus primarily on the development additional juvenile free systems by the use of another pear variety and manipulation of the FT gene under the control of several promoters. Based on the results creation of fire blight resistance pear variety was developed by the use of the juvenile free transgenic plant. Background: Young tree seedlings are unable to initiate reproductive organs and require a long period of shoot maturation, known as juvenile phase. In pear, juvenile period can last 5-7 years and it causes a major delay in breeding programs. We isolated the TFL1 gene from Spadona pear (PcTFL1-1) and produced transgenic ‘Spadona’ trees silencing the PcTFL1 gene using a RNAi approach. Transgenic tissue culture ‘Spadona’ pear flowered in vitro. As expected, the expression of the endogenous PcTFL1 was suppressed in the transgenic line that showed precocious flowering. Transgenic plants were successfully rooted in the greenhouse and most of the plants flowered after only 4-8 months, whereas the non-transformed control plants have flowered only after 5-6 years of development. Major achievements: Prior to flower induction, transgenic TFL1-RNAi ‘Spadona’ plants developed a few branches and leaves. Flower production in the small trees suppressed the development of the vegetative branches, thus resulting in compact flowering trees. Flowering was initiated in terminal buds, as described for the Arabidopsis tfl1 mutant. Propagation of the transgenic TFL1-RNAi ‘Spadona’ was performed by bud grafting on 'Betulifolia' rootstock and resulted in compact flowering trees. The transgenic flowering grafted plants were grown in the greenhouse under a long photoperiod for one year, and flowered continuously. Pollination of the transgenic flowers with ‘Costia‘ pear pollen generated fruits of regular shape with fertile F1 seeds. The F1 transgenic seedling grown in the greenhouse formed shoots and produced terminal flowers only five months after germination. In addition, grafted F1 transgenic buds flower and fruit continuously, generating hybrid fruits with regular shape, color and taste. Several pear varieties were pollinated with the transgenic TFL1-RNAi ‘Spadona’ pollen including `Herald Harw` that was reported to have resistance to fire blight diseases. The F-1 hybrid seedlings currently grow in our greenhouse. We conclude that the juvenile-free transgenic ‘Spadona’ pear enables the development of a fast breeding method in pear that will enable us to generate a resistance pear to fire blight. Implications: The research supported by this grant has demonstrated the use of transgenic juvenile free technology in pear. The use of the juvenile free technology for enhancement of conventional breeding in fruit tree will serve to enhance fast breeding systems in pear and another fruit trees.
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Guy, Charles, Gozal Ben-Hayyim, Gloria Moore, Doron Holland, and Yuval Eshdat. Common Mechanisms of Response to the Stresses of High Salinity and Low Temperature and Genetic Mapping of Stress Tolerance Loci in Citrus. United States Department of Agriculture, 1995. http://dx.doi.org/10.32747/1995.7613013.bard.
Full textAbstract:
The objectives that were outlined in our original proposal have largely been achieved or will be so by the end of the project in February 1995 with one exception; that of mapping cold tolerance loci based on the segregation of tolerance in the BC1 progeny population. Briefly, our goals were to 1) construct a densely populated linkage map of the citrus genome: 2) map loci important in cold and/or salt stress tolerance; and 3) characterize the expression of genes responsive to cold land salt stress. As can be seen by the preceding listing of accomplishments, our original objectives A and B have been realized, objective C has been partially tested, objective D has been completed, and work on objectives E and F will be completed by the end of 1995. Although we have yet to map any loci that contribute to an ability of citrus to maintain growth when irrigated with saline water, our very encouraging results from the 1993 experiment provides us with considerable hope that 1994's much more comprehensive and better controlled experiment will yield the desired results once the data has been fully analyzed. Part of our optimism derives from the findings that loci for growth are closely linked with loci associated with foliar Cl- and Na+ accumulation patterns under non-salinization conditions. In the 1994 experiment, if ion exclusion or sequestration traits are segregating in the population, the experimental design will permit their resolution. Our fortunes with respect to cold tolerance is another situation. In three attempts to quantitatively characterize cold tolerance as an LT50, the results have been too variable and the incremental differences between sensitive and tolerant too small to use for mapping. To adequately determine the LT50 requires many plants, many more than we have been able to generate in the time and space available by making cuttings from small greenhouse-grown stock plants. As it has turned out, with citrus, to prepare enough plants needed to be successful in this objective would have required extensive facilities for both growing and testing hardiness which simply were not available at University of Florida. The large populations necessary to overcome the variability we encountered was unanticipated and unforeseeable at the project's outset. In spite of the setbacks, this project, when it is finally complete will be exceedingly successful. Listing of Accomplishments During the funded interval we have accomplished the following objectives: Developed a reasonably high density linkage map for citrus - mapped the loci for two cold responsive genes that were cloned from Poncirus - mapped the loci for csa, the salt responsive gene for glutathione peroxidase, and ccr a circadian rhythm gene from citrus - identified loci that confer parental derived specific DNA methylation patterns in the Citrus X Poncirus cross - mapped 5 loci that determine shoot vigor - mapped 2 loci that influence leaf Na+ accumulation patterns under non-saline conditions in the BC1 population - mapped 3 loci that influence leaf Na+ accumulation paterns during salt sress - mapped 2 loci that control leaf Cl- accumulation patterns under non-saline conditions - mapped a locus that controls leaf Cl- accumulation patterns during salt stress Screened the BC1 population for growth reduction during salinization (controls and salinized), and cold tolerance - determined population variation for shoot/root ratio of Na+ and Cl- - determined levels for 12 inorganic nutrient elements in an effort to examine the influence of salinization on ion content with emphasis on foliar responses - collected data on ion distribution to reveal patterns of exclusion/sequestration/ accumulation - analyzed relationships between ion content and growth Characterization of gene expression in response to salt or cold stress - cloned the gene for the salt responsive protein csa, identified it as glutathione peroxidase, determined the potential target substrate from enzymatic studies - cloned two other genes responsive to salt stress, one for the citrus homologue of a Lea5, and the other for an "oleosin" like gene - cold regulated (cor) genes belonging to five hybridization classes were isolated from Poncirus, two belonged to the group 2 Lea superfamily of stress proteins, the others show no significant homology to other known sequences - the expression of csa during cold acclimation was examined, and the expression of some of the cor genes were examined in response to salt stress - the influence of salinization on cold tolerance has been examined with seedling populations - conducted protein blot studies for expression of cold stress proteins during salt stress and vice versa
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Chamovitz, Daniel A., and Albrecht G. Von Arnim. eIF3 Complexes and the eIF3e Subunit in Arabidopsis Development and Translation Initiation. United States Department of Agriculture, 2009. http://dx.doi.org/10.32747/2009.7696545.bard.
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The original working hypothesis of our proposal was that The “e” subunit of eIF3 has multiple functions from both within the nucleus and in the cytoplasm. Within this model, we further hypothesized that the “e” subunit of eIF3 functions in translation as a repressor. We proposed to test these hypotheses along the following specific aims: 1) Determine the subcellular localization of the interaction between eIF3e and other eIF3 subunits, or the COP9 signalosome. 2) Elucidate the biological significance of the varied subcellular localizations of eIF3e through generating Arabidopsis eIF3e alleles with altered subcellular localization. 3.) Purify different eIF3e complexes by tandem affinity purification (TAP). 4) Study the role of eIF3e in translational repression using both in vitro and in planta assays. eIF3 is an evolutionarily ancient and essential component of the translational apparatus in both the plant and animal kingdoms. eIF3 is the largest, and in some ways the most mysterious, of the translation factors. It is a multi-subunit protein complex that has a structural/scaffolding role in translation initiation. However, despite years of study, only recently have differential roles for eIF3 in the developmental regulation of translation been experimentally grounded. Furthermore, the roles of individual eIF3 subunits are not clear, and indeed some, such as the “e” subunit may have roles independent of translation initiation. The original three goals of the proposal were technically hampered by a finding that became evident during the course of the research – Any attempt to make transgenic plants that expressed eIF3e wt or eIF3e variants resulted in seedling lethality or seed inviability. That is, it was impossible to regenerate any transgenic plants that expressed eIF3e. We did manage to generate plants that expressed an inducible form of eIF3e. This also eventually led to lethality, but was very useful in elucidating the 4th goal of the research (Yahalom et al., 2008), where we showed, for the first time in any organism, that eIF3e has a repressory role in translation. In attempt to solve the expression problems, we also tried expression from the native promoter, and as such analyzed this promoter in transgenic plants (Epel, 2008). As such, several additional avenues were pursued. 1) We investigated protein-protein interactions of eIF3e (Paz-Aviram et al., 2008). 2) The results from goal #4 led to a novel hypothesis that the interaction of eIF3e and the CSN meets at the control of protein degradation of nascent proteins. In other words, that the block in translation seen in csn and eIF3e-overexpressing plants (Yahalom et al., 2008) leads to proteasome stress. Indeed we showed that both over expression of eIF3e and the csn mutants lead to the unfolded protein response. 3) We further investigated the role of an additional eIF3 subunit, eIF3h, in transalational regulation in the apical meristem (Zhou et al., 2009). Epel, A. (2008). Characterization of eIF3e in the model plant Arabidopsis thaliana. In Plant Sciences (Tel Aviv, Tel Aviv University). Paz-Aviram, T., Yahalom, A., and Chamovitz, D.A. (2008). Arabidopsis eIF3e interacts with subunits of the ribosome, Cop9 signalosome and proteasome. Plant Signaling and Behaviour 3, 409-411. Yahalom, A., Kim, T.H., Roy, B., Singer, R., von Arnim, A.G., and Chamovitz, D.A. (2008). Arabidopsis eIF3e is regulated by the COP9 signalosome and has an impact on development and protein translation. Plant J 53, 300-311. Zhou, F., Dunlap, J.R., and von Arnim, A.G. The translation initiation factor subunit eIF3h is .1 involved in Arabidopsis shoot apical meristem maintenance and auxin response. (submitted to Development).
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Sela, Hanan, Eduard Akhunov, and Brian J. Steffenson. Population genomics, linkage disequilibrium and association mapping of stripe rust resistance genes in wild emmer wheat, Triticum turgidum ssp. dicoccoides. United States Department of Agriculture, 2014. http://dx.doi.org/10.32747/2014.7598170.bard.
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The primary goals of this project were: (1) development of a genetically characterized association panel of wild emmer for high resolution analysis of the genetic basis of complex traits; (2) characterization and mapping of genes and QTL for seedling and adult plant resistance to stripe rust in wild emmer populations; (3) characterization of LD patterns along wild emmer chromosomes; (4) elucidation of the multi-locus genetic structure of wild emmer populations and its correlation with geo-climatic variables at the collection sites. Introduction In recent years, Stripe (yellow) rust (Yr) caused by Pucciniastriiformis f. sp. tritici(PST) has become a major threat to wheat crops in many parts of the world. New races have overcome most of the known resistances. It is essential, therefore, that the search for new genes will continue, followed by their mapping by molecular markers and introgression into the elite varieties by marker-assisted selection (MAS). The reservoir of genes for disease and pest resistance in wild emmer wheat (Triticumdicoccoides) is an important resource that must be made available to wheat breeders. The majority of resistance genes that were introgressed so far in cultivated wheat are resistance (R) genes. These genes, though confering near-immunity from the seedling stage, are often overcome by the pathogen in a short period after being deployed over vast production areas. On the other hand, adult-plant resistance (APR) is usually more durable since it is, in many cases, polygenic and confers partial resistance that may put less selective pressure on the pathogen. In this project, we have screened a collection of 480 wild emmer accessions originating from Israel for APR and seedling resistance to PST. Seedling resistance was tested against one Israeli and 3 North American PST isolates. APR was tested on accessions that did not have seedling resistance. The APR screen was conducted in two fields in Israel and in one field in the USA over 3 years for a total of 11 replicates. We have found about 20 accessions that have moderate stripe rust APR with infection type (IT<5), and about 20 additional accessions that have novel seedling resistance (IT<3). We have genotyped the collection using genotyping by sequencing (GBS) and the 90K SNP chip array. GBS yielded a total 341K SNP that were filtered to 150K informative SNP. The 90K assay resulted in 11K informative SNP. We have conducted a genome-wide association scan (GWAS) and found one significant locus on 6BL ( -log p >5). Two novel loci were found for seedling resistance. Further investigation of the 6BL locus and the effect of Yr36 showed that the 6BL locus and the Yr36 have additive effect and that the presence of favorable alleles of both loci results in reduction of 2 grades in the IT score. To identify alleles conferring adaption to extreme climatic conditions, we have associated the patterns of genomic variation in wild emmer with historic climate data from the accessions’ collection sites. The analysis of population stratification revealed four genetically distinct groups of wild emmer accessions coinciding with their geographic distribution. Partitioning of genomic variance showed that geographic location and climate together explain 43% of SNPs among emmer accessions with 19% of SNPs affected by climatic factors. The top three bioclimatic factors driving SNP distribution were temperature seasonality, precipitation seasonality, and isothermality. Association mapping approaches revealed 57 SNPs associated with these bio-climatic variables. Out of 21 unique genomic regions controlling heading date variation, 10 (~50%) overlapped with SNPs showing significant association with at least one of the three bioclimatic variables. This result suggests that a substantial part of the genomic variation associated with local adaptation in wild emmer is driven by selection acting on loci regulating flowering. Conclusions: Wild emmer can serve as a good source for novel APR and seedling R genes for stripe rust resistance. APR for stripe rust is a complex trait conferred by several loci that may have an additive effect. GWAS is feasible in the wild emmer population, however, its detection power is limited. A panel of wild emmer tagged with more than 150K SNP is available for further GWAS of important traits. The insights gained by the bioclimatic-gentic associations should be taken into consideration when planning conservation strategies.
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Porat, Ron, Doron Holland, and Linda Walling. Identification of Citrus Fruit-Specific and Pathogen-Induced Promoters and Their Use in Molecular Engineering. United States Department of Agriculture, 2001. http://dx.doi.org/10.32747/2001.7585202.bard.
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This one year BARD project was funded to develop methods to monitor promoter activity a gene expression patterns in citrus fruit. To fulfill this goal, we divided the research tasks between both labs so that the Israeli side evaluated the use of microprojectile bombardment ; a tool to evaluate transient gene expression in various citrus fruit tissues, and the US side optimized technical parameters required for Agrobacterium-mediated transformation of various citrus cultivars. Microprojectile bombardment appeared to be a very efficient method for transient gene expression analysis in citrus leaf tissues but was somewhat less applicable in fruit tissues. Nevertheless, we did succeeded to achieve significant levels of 35S-GUS gene expression in young green flavedo tissue. However, only single random spots of 35S-GUS gene expression were detected mature flavedo and in juice sacs and albedo tissue. Overall, we assume that following some more technical improvements particle bombardment could provide a useful technique to rapidly analyze promoter activity at least in the flavedo tissue. For Agrobacterium-mediated transformation, we found that shoot cultures of 'Washington' navel oranges,'Fairchild' mandarins,'Eureca' lemons,'Troyer' citrange and various grapefruits provided a more reliable and consistent source of tissue for transformation than germinated seedlings. Moreover, various growth media's (McCown, Quoirin & Lepoivre, DCR) further improved shoot and root growth relative to MS mineral media, which is commonly used. Also pure white light (using bulbs which do not emit UV or blue light) improved shoot growth in various citrus varieties, and paromomycin appeared to be a more efficient antibiotic for the selection of transgenic plants than Kanamycin. Overall, these optimizations improve transformation efficacy and shoot growth and rooting capacity. In addition to the development of transformation methods, both Israeli and US labs achieved progress in the identification of citrus fruit-specific promoters. In Israel, we isolated a 3.6 kb promoter fragment of the thiamine biosynthesis c-thi gene, which is highly expressed in fruit peel tissue, whereas in the US we isolated a 1.5 kb promoter fragment of the citrus seed-specific cDNA CssH. The identification of more fruit-specific cDNAs and their corresponding promoter regions is currently in progress.
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Cherdshewasart, Wichai, Winai Dahlan, and Siriporn Chumruslertluk. The application of DNA demethylation in alteration of phenotypic, seed production, protein lipid content and fatty acid composition in soybean cultivar SJ. 5. Chulalongkorn University, 1999. https://doi.org/10.58837/chula.res.1999.33.
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To evaluate the demethylating effects of 5-azaC on the general phenotypes, protein content, oil content and fatty acid composition at the whole plant system, soybean plants (Glycine max (L.) Merrill) var. SJ.5 have been submitted to 5-azaC treatment. In in vitro culture, seeds were cultured in MS media containing 5-azaC at the concentration of 0, 300, 600, 900, 1200 and 1500 micromolar for 10 days. The 5-azaC-treated seedlings exhibited normal morphology in comparison with the controls except that their height and root length were significantly shorter than that of the controls, and were dose dependent. The isolated genomic DNAs showed hypomethylation as compared with that of the controls. In the field culture, seeds were treated for 16 h with 5-azaC solution at 0, 300, 600, 900, 1200 and 1500 micromolar. The treatment induced tall plant and high node number, without apparently affecting any other developmental processes. Studies on the effects of 5-azaC on the protein and oil content revealed that the alteration in the average protein and oil content of treated seeds were dose independent. The highest protein and oil content were derived from the dosage of 1500 micromolar and 1200 micromolar, respectively. Furthermore, all fatty acid profiles remained unchanged. Genomic DNAs isolated from the selected phenotypes such as tall, high protein and high oil content showed no significant difference in the m[superscript 5]C content in comparison with DNAs from the control samples. The M[subscript 0] showed tall, short, high protein and high oil content and exhibited the inheritance of such phenotypes in the M[subscript 1] plants.
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Leis, Sherry. Plant community trends at Tallgrass Prairie National Preserve: 2002–2023. National Park Service, 2025. https://doi.org/10.36967/2309785.
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The Heartland Inventory and Monitoring Network has monitored vegetation at Tallgrass Prairie National Preserve for more than 20 years. Monitoring assists the preserve in managing the nearly 10,000-acre (4,047 ha) site by providing status and trends of vegetation and disturbance metrics. The site protects critical remnant tallgrass prairie as well as the ranching legacy of the Flint Hills region. Monitoring was conducted in 30 permanent sites across the western preserve. We assessed current and future climate trends, fire and grazing rates, and vegetation metrics, including ground cover, guild, plant diversity, and species composition. We also assessed observer error using a double sampling technique. Historical climate data indicate a trend toward increasing moisture and days with heavy precipitation. Future climate scenarios include the possibility of a warm-wet future with a slight increase in excess moisture (runoff) in the spring and the possibility of a hot-dry future where water deficit spans most of the year. Disturbance intensity continued to be lower since 2006 when management shifted from more of a ranching-based paradigm towards an ecological paradigm with heterogeneity as a central theme (Leis and Morrison 2018). Stocking rates were similar or lighter than the prior monitoring period (2015–2018), and fire return intervals were longer since 2006. Of ground cover metrics, bare areas meet greater prairie chicken habitat thresholds preserve-wide but fall below expectations in two pastures. The native woody plant guild continues to increase in cover in Big and Windmill pastures, but other plant guilds are stable. There was a small increase in tree seedlings, however. Measures of species richness were within the range of variation of prior monitoring events, but Shannon Diversity had a declining trend. Combined with Sørensen index analysis we noted that species composition shifts were likely a key factor in the decline of Shannon Diversity. Pseudoturnover was less than the previous monitoring event—likely the result of having an expert botanist and improved double sampling techniques and communication. Indications of a changing flora coincide with reduced disturbance intensity and a changing climate. An increase in disturbance intensity and/or timing shifts may be needed to avoid detrimental woody plant expansion. Future management actions that take climate scenarios into consideration may also be beneficial. For example, planning fires around changing plant phenology and grazing plans that reduce animal stress and provide adequate water in the event of drought would be beneficial in the short and long term.
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Eshel, Amram, Jonathan P. Lynch, and Kathleen M. Brown. Physiological Regulation of Root System Architecture: The Role of Ethylene and Phosphorus. United States Department of Agriculture, 2001. http://dx.doi.org/10.32747/2001.7585195.bard.
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Specific Objectives and Related Results: 1) Determine the effect of phosphorus availability on ethylene production by roots. Test the hypothesis that phosphorus availability regulates ethylene production Clear differences were found between the two plants that were studied. In beans ethylene production is affected by P nutrition, tissue type, and stage of development. There are genotypic differences in the rate of ethylene production by various root types and in the differential in ethylene production when P treatments are compared. The acceleration in ethylene production with P deficiency increases with time. These findings support the hypothesis that ethylene production may be enhanced by phosphorus deficiency, and that the degree of enhancement varies with genotype. In tomatoes the low-P level did not enhance significantly ethylene production by the roots. Wildtype cultivars and ethylene insensitive mutants behaved similarly in that respect. 2) Characterize the effects of phosphorus availability and ethylene on the architecture of whole root systems. Test the hypothesis that both ethylene and low phosphorus availability modify root architecture. In common bean, the basal roots give rise to a major fraction of the whole root system. Unlike other laterals these roots respond to gravitropic stimulation. Their growth angle determines the proportion of the root length in the shallow layers of the soil. A correlation between ethylene production and basal root angle was found in shallow rooted but not deep-rooted genotypes, indicating that acceleration of ethylene synthesis may account for the change in basal root angle in genotypes demonstrating a plastic response to P availability. Short-time gravitropic response of the tap roots of young bean seedlings was not affected by P level in the nutrient solution. Low phosphorus specifically increases root hair length and root hair density in Arabidopsis. We tested 7 different mutants in ethylene perception and response and in each case, the response to low P was lower than that of the wild-type. The extent of reduction in P response varied among the mutants, but every mutant retained some responsiveness to changes in P concentration. The increase in root hair density was due to the increase in the number of trichoblast cell files under low P and was not mediated by ethylene. Low P did not increase the number of root hairs forming from atrichoblasts. This is in contrast to ethylene treatment, which increased the number of root hairs partly by causing root hairs to form on atrichoblasts. 3) Assess the adaptive value of root architectural plasticity in response to phosphorus availability. A simulation study indicated that genetic variation for root architecture in common bean may be related to adaptation to diverse competitive environments. The fractal dimension of tomato root system was directly correlated with P level.
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Barg, Rivka, Kendal D. Hirschi, Avner Silber, Gozal Ben-Hayyim, Yechiam Salts, and Marla Binzel. Combining Elevated Levels of Membrane Fatty Acid Desaturation and Vacuolar H+ -pyrophosphatase Activity for Improved Drought Tolerance. United States Department of Agriculture, 2012. http://dx.doi.org/10.32747/2012.7613877.bard.
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Background to the topic: In previous works we have shown that Arabidopsis and tomato over-expressing H+-pyrophosphatase show increased tolerance to drought imposed by withholding irrigation of young plants in pots (Park et al. 2005). In addition, young tobacco plants over-expressing fatty acid desaturase 3 (OEX-FAD3) also showed increasing tolerance to drought stress (Zhang et al 2005), and similarly OEX-FAD3 young tomato plants (unpublished data from ARO), hence raising the possibility that pyramiding the two could further improve drought tolerance in tomato. Based on these findings the specific objects originally set were: 1. To analyze the impact of pyramiding transgenes for enhanced fatty acid desaturation and for elevated H+-PPase activity on tomato yielding under water deficit stress conditions. 2. To elucidate the biochemical relationship between elevated desaturation of the membrane lipids and the activities of selected vacuolar transporters in the context of drought responses. 3. To explore the S. pennellii introgression lines as alternative genetic sources for drought tolerance related to enhanced fatty acid desaturation and/or H+-PPase activity. 4. Since OEX-FAD3 increases the levels of linolenic acid which is the precursor of various oxylipins including the stress hormone Jasmonate. (JA), study of the effect of this transgene on tolerance to herbivore pests was added as additional goal. The Major conclusions, solutions, and achievements are: (1) The facts that ectopic over-expression of vacuolarH+-PPases (in line OEX-AVP1) does not change the fatty acid profile compared to the parental MoneyMaker (MM) line and that elevated level of FA desaturation (by OEX-FAD3) does not change the activity of either H+-PPase, H+-ATPaseor Ca2+ /H+ antiport, indicate that the observed increased drought tolerance reported before for increase FA desaturation in tobacco plants and increased H+PPase in tomato plants involves different mechanisms. (2) After generating hybrid lines bringing to a common genetic background (i.e. F1 hybrids between line MP-1 and MM) each of the two transgenes separately and the two transgenes together the effect of various drought stress regimes including recovery from a short and longer duration of complete water withhold as well as performance under chronic stresses imposed by reducing water supply to 75-25% of the control irrigation regime could be studied. Under all the tested conditions in Israel, for well established plants grown in 3L pots or larger, none of the transgenic lines exhibited a reproducible significantly better drought tolerance compare to the parental lines. Still, examining the performance of these hybrids under the growth practices followed in the USA is called for. (3) Young seedlings of none of the identified introgression lines including the S. pennellii homologs of two of the H+-PPase genes and one of the FAD7 genes performed better than line M82 upon irrigation withhold. However, differences in the general canopy structures between the IL lines and M82 might mask such differences if existing. (4). Over-expression of FAD3 in the background of line MP-1 was found to confer significant tolerance to three important pest insects in tomato: Bordered Straw (Heliothis peltigera), Egyptian cotton leafworm (Spodoptera littoralis) and Western Flower Thrips (Frankliniella occidentalis). Implications: Although the original hypothesis that pyramiding these two trasgenes could improve drought tolerance was not supported, the unexpected positive impact on herbivore deterring, as well as the changes in dynamics of JA biosynthesis in response to wounding and the profound changes in expression of wound response genes calls for deciphering the exact linolenic acid derived signaling molecule mediating this response. This will further facilitate breeding for herbivore pest and mechanical stress tolerance based on this pathway.