The cotyledon cell wall and intracellular matrix are factors that limit iron bioavailability of the common bean (Phaseolus vulgaris)

Strategies that enhance the Fe bioavailability of the bean are of keen interest to nutritionists, bean breeders and growers.

Uptake and transport of nutrients and transverse cracking of bean cotyledons

Calcium, Potassium and Magnesium in cotyledon cell walls were negatively correlated with cultivar susceptibility to transverse cracking of cotyledons (TVC). Plant feeding with calcium only slightly changed the percentage of TVC, and Ca, K and Mg contents in the cotyledon cell walls. Susceptibility to TVC was connected with the causes inherent in the root or shoot. Some disturbances in the displacement of Ca and K through the peduncles and K through the petioles in susceptible cultivars were noticed. These cultivars also immobilized a large quantity of Mg in sterns, and in this connection they actually had less Mg in the fruit walls, seeds, stems and blades than resistant cultivars.

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

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 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.