Demand and supply of N in seed production of soybean (Glycine max) at different N fertilization levels after flowering

作者：Kinugasa Toshihiko^*; Sato Takashi; Oikawa Shimpei; Hirose Tadaki

来源：Journal of Plant Research, 2012, 125(2): 275-281.

DOI：10.1007/s10265-011-0439-5

• Glycine max
• N demand and supply
• N filling rate
• N-2 fixation
• Remobilization
• Seed yield

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.

• 出版日期2012-3