Effects of nitrogen fertilization on the seed quality of soybean(Glycne max. L) and its improvement by using slow-release nitrogen fertilizer.

研究了氮肥施量对大豆种子产量和品质的影响。1)嫁接试验表明，低蛋白种子品种的根系对种子蛋白浓度的影响与生长培养基中氮浓度的响应有关。2)根据植物对氮肥的响应（施氮对籽粒产量的影响），将大豆品种大致分为两类。一是施氮能提高种子产量，二是施氮不影响种子产量。(3)种子最大、外皮黑色的品种丹巴uro，在种子成熟阶段，随着施氮量的增加，其种子大小和籽油含量均有所增加。综上所述，在繁殖阶段吸收的无机氮（肥氮）转化为有机形态（氨基酸），对产量有一定的促进作用。结果表明，施氮可提高种子中油脂含量，抑制固氮可促进种子中油脂的积累。

Effects of the nitrogen fertilizer applications on the yield and quality of soybean seeds were examined.1) Grafting experiments showed that roots from plants of a cultivar having low-protein seeds affected seed protein concentrations responding to concentrations of nitrogen in growth medium.2) Soybean cultivars were roughly classified into two types based on the response of plants against nitrogen fertilizers (changes of the seed yields by nitrogen application). One was that seed yields were increased by nitrogen fertilization and the other was that seed yields were not affected by nitrogen application.3) Tanbaguro, a cultivar having biggest seeds with black coat, increased its seed size and oil concentration in seeds by the increase of amounts of nitrogen application during seed maturation periods. These results showed that inorganic nitrogen (fertilized nitrogen) absorbed during reproductive stage was converted to organic form (amino acids) and played a some role to increase yields. The observation that oil concentrations in seeds were increased by nitrogen fertilization suggested that suppression of nitrogen fixation would promote oil accumulation in seeds.