scholarly journals Peach Seedling Emergence and Growth in Response to Isothermal and Cycled Stratification Treatments Reveal Two Dormancy Components

1998 ◽  
Vol 123 (5) ◽  
pp. 776-780 ◽  
Author(s):  
Schuyler D. Seeley ◽  
Hamit Ayanoglu ◽  
James W. Frisby
Keyword(s):  
Seedling Growth ◽  
Temperature Effects ◽  
Prunus Persica ◽  
Seedling Emergence ◽  
Normal Growth ◽  
Combined Effect ◽  
Chilling Requirement ◽  
Normal Seedling ◽  
Growth Promoting ◽  
Rapid Emergence

Dormant seeds of `Johnson Elberta' peach [Prunus persica (L.) Batsch] were stratified at constant 2, 6, or 14 °C or cycled between 2 and 14 °C in 12/12, 14/10, 16/8, 20/4, 22/2, or 23/1 h cycles. Emergence (measured every 3 d after planting) and normal seedling growth (measured after 49 d) increased with longer stratifiction durations. Seeds stratified at 2 °C had the most rapid emergence (only 28 d of stratification was required) but seedling growth was abnormal until 70 d of stratification. Isothermal stratification at 6 °C resulted in normal seedlings after 56 d of stratification but quality and quantity of growth improved with stratification up to 70 d. Seeds stratified at 14 °C showed limited improvement in seedling emergence with time; seedling growth was poor and cotyledonary reserves were not used. Seedling growth after cycled stratification treatments gained normalcy faster than in the constant 2 °C treatment. The 22/2 and 20/4 (2/14 °C) cycles produced normal growth after 56 d of stratification that was comparable to the growth produced by the constant 6 °C treatment. Other cycles required 70 d or more for equivalent seedling growth. Improved seedling growth under cycled treatments could be due to developmental or growth promoting temperature effects of 14 °C during stratification or a combined effect of thermal accumulation and chilling occurring together after a minimal chilling requirement has been completed.

Genetic variation for rate of establishment in caucasian clover

1998 ◽  
pp. 213-217
Author(s):  
K.H. Widdup ◽  
T.L. Knight ◽  
C.J. Waters
Keyword(s):  
Genetic Variation ◽  
Root Growth ◽  
Seedling Growth ◽  
White Clover ◽  
Seedling Emergence ◽  
Red Clover ◽  
Dry Weight ◽  
Cool Season ◽  
Trifolium Ambiguum ◽  
Root Dry Weight

Slow establishment of caucasian clover (Trifolium ambiguum L.) is hindering the use of this legume in pasture mixtures. Improved genetic material is one strategy of correcting the problem. Newly harvested seed of hexaploid caucasian clover germplasm covering a range of origins, together with white and red clover and lucerne, were sown in 1 m rows in a Wakanui soil at Lincoln in November 1995. After 21 days, the caucasian clover material as a group had similar numbers of emerged seedlings as white clover and lucerne, but was inferior to red clover. There was wide variation among caucasian clover lines (48-70% seedling emergence), with the cool-season selection from cv. Monaro ranked the highest. Recurrent selection at low temperatures could be used to select material with improved rates of seedling emergence. Red clover and lucerne seedlings produced significantly greater shoot and root dry weight than caucasian and white clover seedlings. Initially, caucasian clover seedlings partitioned 1:1 shoot to root dry weight compared with 3:1 for white clover. After 2 months, caucasian clover seedlings had similar shoot growth but 3 times the root growth of white clover. Between 2 and 5 months, caucasian clover partitioned more to root and rhizome growth, resulting in a 0.3:1 shoot:root ratio compared with 2:1 for white clover. Both clover species had similar total dry weight after 5 months. Unhindered root/ rhizome devel-opment is very important to hasten the establishment phase of caucasian clover. The caucasian clover lines KZ3 and cool-season, both selections from Monaro, developed seedlings with greater shoot and root growth than cv. Monaro. KZ3 continued to produce greater root growth after 5 months, indicating the genetic potential for improvement in seedling growth rate. Different pasture estab-lishment techniques are proposed that take account of the seedling growth characteristics of caucasian clover. Keywords: establishment, genetic variation, growth, seedling emergence, Trifolium ambiguum

Effects of salinity on seedling emergence and early seedling growth of Irvingia gabonensis (Irvingiaceae)

2017 ◽  
Vol 45 (2) ◽  
pp. 282-295
Author(s):  
R. Vihotogbé ◽  
C. Watson ◽  
R. Glèlè Kakaï ◽  
F. Wichern ◽  
B. Sinsin ◽  
...  
Keyword(s):  
Seedling Growth ◽  
Seedling Emergence ◽  
Early Seedling Growth ◽  
Early Seedling ◽  
Irvingia Gabonensis

EMERGENCE AND SEEDLING GROWTH OF INBRED LINES OF CORN AT SUBOPTIMAL ROOT-ZONE TEMPERATURES

1987 ◽  
Vol 67 (2) ◽  
pp. 409-415 ◽  
Author(s):  
A. MENKIR ◽  
E. N. LARTER
Keyword(s):  
Zea Mays ◽  
Seedling Growth ◽  
Root Zone ◽  
Seedling Emergence ◽  
Correlation Coefficients ◽  
Dry Weight ◽  
Inbred Lines ◽  
Root Zone Temperature ◽  
Emergence Percentage ◽  
Zone Temperature

Based on the results of an earlier paper, 12 inbred lines of corn (Zea mays L.) were evaluated for emergence and seedling growth at three controlled root-zone temperatures (10, 14, and 18 °C). Low root-zone temperatures, 10 and 14 °C, were detrimental to emergence, seedling growth, and root growth of all inbred lines. Differential responses of inbred lines were observed within each temperature regime. The differences in seedling emergence among lines became smaller with increasing root-zone temperature, while the reverse was true for seedling dry weight. Simple correlation coefficients showed a significantly (P = 0.05) negative association between emergence percentage and emergence index (rate). Neither of these two emergence traits was significantly correlated with seedling dry weights. Seedling dry weights were significantly (P = 0.01) and positively associated with root dry weights. Two inbred lines exhibited good tolerance to low root-zone temperatures, viz. CO255 and RB214. A significant and positive correlation existed between emergence percentage at a root-zone temperature of 10 °C and field emergence in test with the same genotypes reported earlier. Selection at a root-zone temperature of 10 °C for a high percentage of seedling emergence, therefore, could be effective in identifying genotypes capable of germinating in cool soils. Furthermore, the significantly (P = 0.01) positive relationship between seedling dry weights at all root-zone temperatures and those from the field test suggest that strains with vigorous seedling growth in the field could be identified using low root-zone temperature regimes.Key words: Zea mays, root-zone temperature, cold tolerance

scholarly journals Mapping quantitative trait loci associated with chilling requirement, heat requirement and bloom date in peach (Prunus persica)

2009 ◽  
Vol 185 (4) ◽  
pp. 917-930 ◽  
Author(s):  
Shenghua Fan ◽  
Douglas G. Bielenberg ◽  
Tetyana N. Zhebentyayeva ◽  
Gregory L. Reighard ◽  
William R. Okie ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Prunus Persica ◽  
Chilling Requirement ◽  
Trait Loci ◽  
Heat Requirement ◽  
Bloom Date

scholarly journals The Growth-Promoting and Stress Response Activities of the Bacillus subtilis GTP Binding Protein Obg Are Separable by Mutation

2008 ◽  
Vol 190 (20) ◽  
pp. 6625-6635 ◽  
Author(s):  
Shrin Kuo ◽  
Borries Demeler ◽  
W. G. Haldenwang
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Amino Acid ◽  
Binding Protein ◽  
Normal Growth ◽  
Gtp Binding Protein ◽  
Missense Change ◽  
Gtp Binding ◽  
Growth Promoting ◽  
Carboxy Terminal

ABSTRACT Bacillus subtilis Obg is a ribosome-associating GTP binding protein that is needed for growth, sporulation, and induction of the bacterium's general stress regulon (GSR). It is unclear whether the roles of Obg in sporulation and stress responsiveness are direct or a secondary effect of its growth-promoting functions. The present work addresses this question by an analysis of two obg alleles whose phenotypes argue for direct roles for Obg in each process. The first allele [obg(G92D)] encodes a missense change in the protein's highly conserved “obg fold” region. This mutation impairs cell growth and the ability of Obg to associate with ribosomes but fails to block sporulation or the induction of the GSR. The second obg mutation [obg(Δ22)] replaces the 22-amino-acid carboxy-terminal sequence of Obg with an alternative 26-amino-acid sequence. This Obg variant cofractionates with ribosomes and allows normal growth but blocks sporulation and impairs the induction of the GSR. Additional experiments revealed that the block on sporulation occurs early, preventing the activation of the essential sporulation transcription factor Spo0A, while inhibition of the GSR appears to involve a failure of the protein cascade that normally activates the GSR to effectively catalyze the reactions needed to activate the GSR transcription factor (σB).

Factors influencing germination of Scolochloa festucacea caryopses

1972 ◽  
Vol 50 (11) ◽  
pp. 2085-2092 ◽  
Author(s):  
Alan L. Smith
Keyword(s):  
Ethyl Alcohol ◽  
Seedling Growth ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Anaerobic Conditions ◽  
Factors Influencing

Germination and seedling emergence increased with increasing caryopses weight in Scolochloa festucacea. Maximum seedling survival occurred when caryopses were planted 1 cm deep. Simulation of anaerobic conditions by soaking caryopses increased seedling emergence. Seedling emergence increased after imbibed caryopses were treated in a N2 atmosphere. Emergence also was increased by soaking caryopses in 95% ethyl alcohol up to 60 min. Stratification apparently improved germination but was not a requirement. Scolochloa festucacea caryopses were more tolerant of MgCl2 than NaCl in the germination media. Optimum seedling growth occurred at 20C.

scholarly journals Exogenous Antioxidants Enhance Seedling Growth and Yield of Artificially Aged Cabbage and Lettuce Seeds

Horticulturae ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 274
Author(s):  
Ademola Adetunji ◽  
Sershen ◽  
Boby Varghese ◽  
Norman Pammenter
Keyword(s):  
Leaf Area ◽  
Seedling Growth ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Growth And Yield ◽  
Seed Vigour ◽  
Beneficial Effects ◽  
Shoot Dry Weight ◽  
Antioxidant Defence System ◽  
Aged Seeds

Aged seeds exhibit compromised vigour in terms of germination, seedling emergence and growth, but this can to some extent be alleviated by invigoration treatments before sowing. This study aimed to investigate ageing rates and patterns in cabbage (Brassica oleraceae) and lettuce (Lactuca sativa) seeds and whether the beneficial effects of invigorating aged seeds with exogenous antioxidants translate to enhanced seedling performance. Seeds were artificially aged to 25% viability before soaking in 0.4 mM glycerol, 0.6 mM GSH and 0.2 mM trolox for cabbage, and 0.6 mM glycerol, GSH and trolox for lettuce; deionised water served as a control. After 14 days of sowing, seedling emergence percentage, mean emergence time, mean daily emergence, and time taken to 25% emergence were computed. Seedling vigour index, root and shoot dry weight, root:shoot ratio, leaf area, leaf area ratio, and leaf chlorophyll content were assessed 6 weeks after sowing. Furthermore, the photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E), and chlorophyll fluorescence were measured 6 weeks after sowing. Notably, ageing resulted in the loss of seed vigour and viability at higher rates in lettuce than cabbage. Seed pretreatment with glycerol promoted seedling growth in both species and shoot dry weight in lettuce, while glycerol and GSH enhanced Pn, Gs and E in lettuce. Trolox also enhanced Pn and E in lettuce. The beneficial effects of the antioxidant treatments are thought to be associated with the protection of photosystems from oxidative stress and/or stimulation of enzymes involved in photosynthesis, possibly through an enhanced antioxidant defence system during the early development stages when seedlings are particularly vulnerable to stress.

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