Endogenous hormones in seed, leaf, and pod wall and their relationship to seed filling in soybeans

2010 ◽  
Vol 61 (2) ◽  
pp. 103 ◽  
Author(s):  
Bing Liu ◽  
Xiao-bing Liu ◽  
Cheng Wang ◽  
Jian Jin ◽  
S. J. Herbert

In order to investigate the possible relationship between endogenous hormones and seed filling in soybeans, concentrations of abscisic acid (ABA), gibberellins (GA3), indole-3-acetic acid (IAA), and cytokinins (ZR) in seed, leaf, and pod wall were determined during seed filling of 3 soybean cultivars differing in seed size and quality. All cultivars were grown at 3 densities. The large-seeded cultivar had a strong and greater ability to accumulate photosynthate during seed filling. The genetic trait of seed size was fully expressed at low density. The large-seeded cultivar had a much higher ABA concentration in seed than the moderate and small-seeded cultivars before physiological maturity. ABA concentration in the large-seeded cultivar seed was 40% greater than that of the small-seeded cultivar at 30 days after flowering. Higher densities increased ABA concentrations in seeds. Two peaks of seed GA3 concentration were observed during seed filling. GA3 concentrations at all densities were similar. The peaks of IAA concentration in the 3 cultivars uniformly occurred at 50 days after flowering. The large-seeded cultivar had greater peak concentrations of GA3 and IAA in seed than the other cultivars, while the peak concentration of ZR was highest in the small-seeded cultivar. The concentrations of ABA in leaf increased with time while that of GA3 decreased. The large-seeded cultivar had higher ABA and IAA concentration in leaf while the small-seeded cultivar consistently had higher GA3 concentration in leaf. ZR was present in a smaller amount in the leaf, and was not detected in the pod wall. The large-seeded cultivar maintained higher IAA concentration in pod wall. ABA concentration in seed was positively correlated with seed-filling rate (P < 0.01, r = 0.85**, 0.92**, and 0.83** for large-, moderate- and small-seeded cultivars respectively).The concentration of GA3 in seed was significantly correlated with the seed-filling rate in large- and moderate-seeded cultivars (P < 0.01, r = 0.87**; P < 0.05, r = 0.63*), and no correlation was found for the small-seeded cultivar. There was no correlation between the concentrations of seed IAA, ZR, and seed-filling rate. There was a parallel relationship between seed growth and leaf/pod wall ABA concentration. Thus, ABA might offer a driving force for photosynthate phloem unloading in the seed coat. Lower concentration of ABA and GA3 in the leaf than in seed suggests that most of the two hormones is transported to seed. The mechanism of IAA in seed growth and GA3 concentration and its dynamic in seed quality need further investigation.

2011 ◽  
Vol 52 (No. 4) ◽  
pp. 178-185 ◽  
Author(s):  
X. Liu ◽  
S.J. Herbert ◽  
K. Baath ◽  
A.M. Hashemi

Seeds are the primary sinks for photosynthates during reproductive growth. Variation in light intercepted during and after seed initiation has been found a major environmental determinant of soybean [Glycine max(L.) Merrill] seed size. We investigated the influence of light enrichment and shading on seed growth rate, effective filling, cotyledon cell number, cell volume and endogenousABA concentrations of cotyledons/testas during seed filling of soybean. Evans, an indeterminate Group 0 soybean, was subjected to light reduction and enrichment treatments from the beginning of pod formation until final harvest for two years inMassachusetts. Higher rates of seed growth, greater seed dry weight, and higher cotyledon cell number were all observed with light enrichment. There was a&nbsp;reduction in seed growth rate and cotyledon cell number, along with a significant lowering of endogenousABA levels in testa and cotyledon with shade. The level ofABAin cotyledon during seed development was significantly correlated with seed growth rates only under shade treatments. Both the growth rates and seed filling duration were influenced by variation in light interception by the soybean canopy. The effects of varying light treatment on seed size, within one genotype, were most likely due to the differences in seed growth rate and cotyledon cell number.


2011 ◽  
Vol 62 (6) ◽  
pp. 481 ◽  
Author(s):  
X.-W. Fang ◽  
N. C. Turner ◽  
F.-M. Li ◽  
K. H. M. Siddique

Terminal drought is known to decrease flower production, increase flower and pod abortion, and decrease yield of chickpea (Cicer arietinum L.), but the effects of early-season drought have not been evaluated. The influence of an early transient water deficit on flower and pod production and abortion, and seed yield and its components was evaluated in two chickpea cultivars, Rupali, a desi type, and Almaz, a kabuli type. Thirty-six-day-old plants were subjected to: (i) a transient water deficit by withholding water for 35 days, and then rewatered (WS), and (ii) kept well watered (WW) throughout. In the WS treatment the soil water content, leaf relative water content and leaf photosynthetic rate decreased after water was withheld and, following rewatering, recovered to the WW level. Despite the WS treatment being imposed at different phenological stages in the two cultivars, WS reduced flower number per plant by ~50% in Rupali and Almaz, respectively, compared with the WW plants. In WW plants, ~15% of flowers aborted in both cultivars, and 42 and 67% of the pods aborted in Rupali and Almaz, respectively, whereas in WS plants, 18 and 23% of flowers aborted and 27 and 67% of pods aborted in Rupali and Almaz, respectively. While seed growth in WS plants of Rupali and Almaz occurred primarily after the plants were rewatered, the duration of seed growth decreased by 17 and 36 days, the maximum rate of seed filling increased by 3 times and 5 times, and seed size increased by 26 and 16%, respectively, compared with the WW plants. Seed yield per plant in WS plants decreased by 31% in Rupali and 38% in Almaz compared with the WW controls. The early transient water deficit decreased flower production, but improved flower and pod development; increased the rate of seed growth and increased final seed size; and had a smaller effect on seed yield compared with chickpea subjected to terminal drought.


2006 ◽  
Vol 18 (3) ◽  
pp. 359-365 ◽  
Author(s):  
Rogério M. Suzuki ◽  
Gilberto B. Kerbauy

This study attempted to clarify the effects of dark, light and ethylene on plant growth and endogenous levels of indole-3-acetic acid (IAA), cytokinins and abscisic acid in Catasetum fimbriatum. Dark-incubation fully inhibited root and pseudobulb formation as well as leaf growth, but favored shoot elongation. The results of continuous and active growth in dark-incubated shoots (stolons) were induced by strong apical meristem sink activity and by the significantly increased levels of cytokinins in shoots. In fact, shoot length, cytokinin and IAA levels in dark-incubated shoots were about twice as great as for those grown under light conditions. Moreover, the total cytokinin level in shoots of C. fimbriatum under light conditions without ethylene was significantly higher than that found in roots. High levels of cytokinins in dark-grown stolons may be closely related to the absence of roots in C. fimbriatum. Under light conditions, the increased IAA level in shoots is mediated by ethylene. However, ethylene caused a significant increase of cytokinins in roots of light-treated plants, which may be involved in the retardation of root growth. Since the difference of cytokinins in shoots between ethylene-treated and non-treated plants under light conditions is small, it is concluded that the marked inhibition of leaf growth in ethylene-treated plants can be attributed to ethylene. Zeatin and zeatin riboside are the major cytokinins in C. fimbriatum regardless of the light conditions, ethylene treatment or organ types.


2019 ◽  
Vol 29 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Richard H. Ellis

AbstractThe long-standing hypothesis that seed quality improves during seed filling, is greatest at the end of seed filling, and declines thereafter (because seed deterioration was assumed to begin then), provided a template for research in seed quality development. It was rejected by investigations where seed quality was shown to improve throughout both seed development and maturation until harvest maturity, before seed deterioration was first observed. Several other temporal patterns of seed quality development and decline have also been reported. These are portrayed and compared. The assessment suggests that the original hypothesis was too simple, because it combined several component hypotheses: (a) the seed improvement (only) phase ends before seed deterioration (only) commences; (b) there is only a brief single point in time during seed development and maturation when, in all circumstances, seed quality is maximal; (c) the seed quality improvement phase coincides perfectly with seed filling, with deterioration only post-seed filling. It is concluded that the search for the single point of maximum seed quality was a false quest because (a) seed improvement and deterioration may cycle (sequentially if not simultaneously) during seed development and maturation; (b) the relative sensitivity of the rates of improvement and deterioration to environment may differ; (c) the period of maximum quality may be brief or extended. Hence, when maximum quality is first attained, and for how long it is maintained, during seed development and maturation varies with genotype and environment. This is pertinent to quality seed production in current and future climates as it will be affected by climate change and a likelihood of more frequent coincidence of brief periods of extreme temperatures with highly sensitive phases of seed development and maturation. This is a possible tipping point for food security and for ecological diversity.


1999 ◽  
Vol 133 (2) ◽  
pp. 141-150 ◽  
Author(s):  
G. F. J. MILFORD ◽  
I. F. SHIELD ◽  
H. J. STEVENSON ◽  
T. SCOTT ◽  
J. E. LEACH

Pod and seed growth were studied in two experiments in which the plant's source-sink relationships were modified by (a) manually pruning an autumn-sown, indeterminate white lupin variety, Lunoble, to a determinate form, and (b) by growing a determinate variety, Lucyane, at densities ranging from 7 to 35 plants/m2. The pruning experiments indicated that the faster pod growth rate of determinate genotypes was not an inherent genetic trait but an indirect physiological consequence of the plant's changed architecture. In the density experiment, crop dry matter (DM) and nitrogen (N) were maximum at the end of pod extension in late July and similar across the plant density range at c. 12 t DM and 320 kg N/ha. Therefore, the amount of dry matter per plant decreased proportionately with the increase in plant number. The DM and N contents of the pod walls were also maximum at the end of pod extension, but seeds contained only a third of their final DM and a quarter of their final N. Protein accumulation during the final stages of seed growth, therefore, depended on the remobilization of nitrogen from other plant organs, primarily the leaves and pod walls. Nitrogen withdrawn from the leaves accounted for 44% of the gain in the pods, and N withdrawn from pod walls for 50–60% of the gain in the seed.Seed number/m2 was the major yield component. Seeds and pods mainly aborted during early development, but seed number per pod was also decreased by some seed abortion after full pod extension, especially in first-order pods of plants grown at high density. The number of late-aborted seeds was negatively correlated with the amount of N remobilized from the pod wall. In determinate lupins, which have highly synchronous flowering and pod development, the large and sudden remobilization of nitrogen from leaves and pod walls for seed growth and protein accumulation triggered crop senescence.


Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 157
Author(s):  
Saveetha Kandasamy ◽  
Nimalka Weerasuriya ◽  
Daniella Gritsiouk ◽  
Greg Patterson ◽  
Soledad Saldias ◽  
...  

Soils with highly uniform textural, physical, and chemical characteristics still give rise to crop stand variability. Seed quality is one of the factors adding to yield variability and has become a concern for corn growers. Hybrid seed producers claim that their seeds provide a uniformity in crop emergence and productivity, but they do not always provide detailed studies to support this claim. Based on growers’ concerns, we examined fields planted with three different hybrid varieties and found that 25% to 50% of the stand had relatively weak vigor, where seed variety A showed 15% of seedlings with lower vigor, and varieties B and C had 30% of seedlings with low vigor. These apparent differences in plant vigor prompted us to initiate a cursory investigation to identify how seed size influenced seedling vigor and if the seedling’s microbial profile played a role in the early growth stages of three commonly grown corn hybrids in Ontario. Seeds were separated based on size, prior to conducting a growth room study. Different sizes of seeds from the same seed lot showed significant differences in vigor capacity and related biometric components. Significant differences were also found in their nutritional composition and microbial profiles within the different seed sizes and the roots and shoots of seedlings derived from such seeds. The results clearly indicate that seed size greatly impacts the plant growth and its microbiome, resulting in seedlings with different plant vigor, microbiomes, and performance.


1998 ◽  
Vol 49 (1) ◽  
pp. 63 ◽  
Author(s):  
J. A. Palta ◽  
C. Ludwig

The effect of pod number on the seed yield and components of seed yield was examined for narrow-leafed lupin (Lupinus angustifolius L.) grown at a plant density of 36 plants/m2 in both the glasshouse and the field. Diflerent numbers of pods per plant in the glasshouse-grown lupin were generated by the application of N6-benzylaminopurine (BAP) to a specific number of flowers to ensure artificially that they set pods, and the subsequent removal of the remaining untreated flowers. Pod number ranged from 6 to 65 pods/plant in the glasshouse and was naturally distributed from 2 to 22 pods/plant in the field. Increases in seed yield per plant occurred as pod number per plant increased from 2 to 30 pods. No further increases in seed yield resulted when pod number per plant increased from 30 to 55 pods. Seed yield per plant was depressed as pod number increased from 55 to 65 pods. Seed size fell as pod number per plant increased over 20 pods and was less affected once the number of seeds per pod was reduced. The reduction in seed number per pod resulted from an increase in the number of seeds that aborted during seed filling. The data suggest that at a plant density of 36 plants/m2 there is potential for improving seed yield per plant by increasing the number of pods that reach maturity, provided it does not exceed 30 pods/plant. However, if consideration is given to producing large seeds, often preferred by buyers, the number of pods per plant should not exceed 20 pods.


2016 ◽  
Vol 113 (44) ◽  
pp. 12414-12419 ◽  
Author(s):  
Liangfa Ge ◽  
Jianbin Yu ◽  
Hongliang Wang ◽  
Diane Luth ◽  
Guihua Bai ◽  
...  

Plant organs, such as seeds, are primary sources of food for both humans and animals. Seed size is one of the major agronomic traits that have been selected in crop plants during their domestication. Legume seeds are a major source of dietary proteins and oils. Here, we report a conserved role for the BIG SEEDS1 (BS1) gene in the control of seed size and weight in the model legume Medicago truncatula and the grain legume soybean (Glycine max). BS1 encodes a plant-specific transcription regulator and plays a key role in the control of the size of plant organs, including seeds, seed pods, and leaves, through a regulatory module that targets primary cell proliferation. Importantly, down-regulation of BS1 orthologs in soybean by an artificial microRNA significantly increased soybean seed size, weight, and amino acid content. Our results provide a strategy for the increase in yield and seed quality in legumes.


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