Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan.
J Plant Res. 2012 Mar;125(2):275-81. doi: 10.1007/s10265-011-0439-5. Epub 2011 Jun 14.
Nitrogen (N) has been suggested as a determinant of seed production especially in species with high seed N content. Assuming that seed yield was determined as the balance between N demand and supply for seed production, we studied the effect of N fertilization after flowering on soybean (Glycine max L. Merr.) yield. Seed N concentration was nearly constant irrespective of N fertilization, indicating that seed production was proportional to the amount of N available for seed growth. N demand for seed production was analyzed as the product of seed number, the rate of N filling in individual seeds, and the length of the reproductive period. N fertilization increased seed number and the reproductive period, but did not influence the N filling rate. Seed number was positively correlated with dry mass productivity after flowering. Three N sources were distinguished: mineral N uptake, symbiotic N(2) fixation and N remobilization from vegetative body. N fertilization increased N uptake and N remobilization, but lowered N(2) fixation. We concluded that N availability in the reproductive period determined seed yield directly through increasing N supply for seed growth and indirectly through increasing seed N demand with enhanced plant dry mass productivity.
氮（N）被认为是种子产量的决定因素，特别是在种子含氮量高的物种中。假设种子产量是由种子生产的 N 需求和供应之间的平衡决定的，我们研究了开花后 N 施肥对大豆（Glycine max L. Merr.）产量的影响。种子 N 浓度不受 N 施肥的影响几乎保持不变，表明种子生产与可用于种子生长的 N 量成正比。种子生产的 N 需求分析为种子数量、单个种子中 N 填充的速率和繁殖期的长度的乘积。N 施肥增加了种子数量和繁殖期，但不影响 N 填充速率。种子数量与开花后干物质生产力呈正相关。区分了三种 N 源：矿质 N 吸收、共生 N2 固定和来自营养体的 N 再利用。N 施肥增加了 N 吸收和 N 再利用，但降低了 N2 固定。我们得出结论，生殖期的 N 供应通过增加种子生长的 N 供应直接决定种子产量，通过提高植物干物质生产力间接增加种子 N 需求来间接决定种子产量。
