Soybean (Glycine max) seed growth characteristics in response to light enrichment and shading

Abstract

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 endogenous ABA 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 in Massachusetts. Higher rates of seed growth, greater seed dry weight, and higher cotyledon cell number were all observed with light enrichment. There was a reduction in seed growth rate and cotyledon cell number, along with a significant lowering of endogenous ABA levels in testa and cotyledon with shade. The level of ABA in 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.

Effect of Temperature Regimes on Morphological Development of Selected Canola (Brassica napus) Genotypes

“…The increase in PGR from planting to physiological maturity indicated that PGR for all genotypes followed the normal growth rate curve, which usually increases as plant growth duration increase. Similar results have been reported on soybean, barley and maize [45,46,47,48]. Increased PGR from planting to budding at 15/20˚C temperature regime and decrease from budding to flowering and flowering to physiological maturity suggest that increasing the mean night/day temperature from 12.5˚C to 17.5˚C increased PGR during the vegetative growth stage (planting to budding) by increasing the rate of leaf appearance and expansion, but as growth progress the increase in temperature decreased PGR by increasing the rate of leaf senescence and respiratory break down of photosynthates [49,50,51].…”

Soybean yield and yield component distribution across the main axis in response to light enrichment and shading under different densities

“…Decrease of seed size in D27 of H339 in 2007 and D27 of H339 in 2008 might be caused by the greater increase of seed number per plant than increase of available amount of photosynthate synthesized per plant under the light enrichment condition. Liu et al (2006a) noticed that shading (52% light reduction) lowered seed size while Egli et al (1985) reported that shading (60% light reduction) during the linear phase of seed development lowered seed growth rate but did not affect final seed size because of a longer duration of seed growth. In our study, shading (25% light reduction) increased seed size by 7 to 11%, which might be a compensation mechanism to yield loss.…”

Cycle, canopy architecture and yield of common bean genotypes (Phaseolus vulgaris) in Santa Catarina State

“…While studying the problem of low luminosity, Liu et al (2010) and Liu et al (2006) concluded that the occurrence of long periods of greater cloud cover can cause photosynthetic deficiency and, as a consequence, a reduction in yield. According to Santos et al (2003), in common beans, soybeans and weed plants, the yield is generally limited by photosynthetic capacity from the start of pod formation and as a result, a reduction in the rate of photosynthesis causes variations in the grain yield or biomass production.…”