Km. Hirshfield et al., COTYLEDON CELL NUMBER AND CELL-SIZE IN RELATION TO SEED SIZE AND SEEDYIELD OF SOYBEAN, Plant physiology and biochemistry, 31(3), 1993, pp. 395-400
The objective of this study was to determine nutrient-related changes
in cotyledon cell size and cell number. These parameters are known to
be related to genotypic differences in seed size and consequently fina
l seed yield of soybean (Glycine max L. Merr). Greenhouse-grown soybea
n plants received an initial fertilizer (N-P-K) application at plantin
g. Later, two groups of plants received supplemental fertilizer either
at early pod set only (Group I) or at both anthesis and pod set (Grou
p II). Plants in Group I had the highest number of pods, seeds and tot
al seed yield per plant relative to controls and Group III plants. Dry
weight and size (volume) of individual seeds was also the highest in
Group I plants. The number of cells per cotyledon as determined by bot
h counting the cells under a microscope and by measurement of total se
ed DNA indicated that application of supplemental fertilizer at either
stage did not increase the number of cells within each seed. Cell siz
e in Group I and Group II plants was however, 59% and 40% higher than
that of controls, respectively. Enhanced seed yield in Group I plants
appeared to have resulted from increased cell size (and consequently s
eed size) and seeds per plant. Similar results were observed in field-
grown soybeans planted in high density plots. While genotypic differen
ces in soybean seed size may be, to a large extent, determined by cell
number, within a single genotype, seed size may be influenced more by
cotyledon cell size than cell number.