早熟无限结荚习性大豆子粒生长特征

大豆产量潜力受到基因型和环境条件的制约。一种基因型的密度、植株分布决定其对太阳辐射、水分和养分的利用，进而高产的形成。当群体生长所需外界要素之一不能满足时，植株间形成竞争。产量的区域间及年际间差异与这种株间竞争关系密切，最终表现为单位面积内一个或多个产量构成因子的差异，如株荚数、荚粒数、或单粒重(籽粒大小)。本研究探讨籽粒大小在调节不同密度、行距条件下产量差异及年际间产量差异的作用。多点试验表明，籽粒大小在不同节位上及不同籽粒数的荚间差异不大。然而在2粒或3粒荚内，荚基部粒比中部及顶部粒小10%，而且子叶细胞体积差异不大。在改变源库、增强光照或遮阴条件下，籽粒大小发生变化。籽粒大小与子叶细胞数相关。籽粒大小是可塑的，但即使底部节位荚较顶部节位提前15~20 d鼓粒，籽粒大小在所有节位间差异不大，所以籽粒大小与子叶细胞数的关系仍值得探讨。

Seed Growth Characteristics of Some Short Season Indeterminate Soybeans

The potential yield of a soybean crop is very specific to the genotype and the environment in which it is grown. For a given genotype, the interaction of density with arrangements of plants will play a key role in determining the competition for available resources especially solar radiation, water and nutrients, and thus maximum yield. Inter-plant competition begins when the immediate supply of a single necessary factor falls below the combined demands of all plants. Variation in yield among fields or years will be related to such inter-plant competition and borne out in one or more of the seed yield components of, plant per unit area, pods per plant, seeds per pod or weight per seed (seed size). This paper discusses the yield component of seed size in regulating differences in seed yield with changes in density and row spacing, and differences in seed yield between different years. Several field studies are reviewed where seed size was shown to be similar between nodes on a plant and in pods with varying seed number. However, the basal seed in two and three-seeded pods for many varieties tested was approximately 10% smaller than the middle or terminal seeds. Cotyledon cell number in basal seeds was 10% less than in middle or terminal seeds and all had similar cotyledon cell size. To test this further, we changed seed size through artificially source-sink manipulation, and by light enrichment and shading. Differences in seed size were also related to differences in cotyledon cell number. This relationship of seed size to cell number is intriguing since with induced changes in seed size, seeds at all nodes were of similar size even though lower nodes began filling 15 to 20 days before upper nodes.