Partitioning of 15N Applied at Reproductive Stages among Grains and in Grain Tissues of Rice Plants

Japanese Journal of Crop Science

Yasuhiro KONO¹  Kunio OKANO¹ 

关键词: Competition;    イネ;    Grain;    ç©Žæžœ;    ^<15>N;    Nitrogen;    競合;    Partitioning;    穂上位置;    Position on panicle;    窒素;    Rice;    登熟;    Ripening.;    分配.;   

DOI  :  10.1626/jcs.62.577

学科分类：农业科学（综合）

来源: Nihon Sakumotsu Gakkai / Crop Science Society of Japan

【 摘 要 】

Hydroponically-grown rice (Oryza sativa L.) plants were pulse-labelled with 15N-ammonium sulphate at various stages of reproductive growth, and partitioning of 15N among grains or grain tissues were examined at full maturity for a better understanding of the ripening process of rice panicle, which consisted of a large number of grains. Labelled nitrogen applied before heading was equally distributed to all grains. 15N applied at heading or the milk-ripe stage was mainly distributed to the early developing grains located on the upper part of the panicle, while that administered at a later period of ripening was principally transported to the later developing grains on the basal part. Thus, the position of grains actively accumulating nitrogen moved down from the upper to the basal part of the panicle with ripening. Active incorporation of 15N into husk continued up to the milk-ripe stage. At the later stages of grain filling, 15N uptake in the embryo became lower than that in the endosperm, indicating the formation of embryo preceded the endosperm. 15N levels incorporated into the inner parts of the endosperm decreased earlier than the outer parts ; this suggested that the deposition of nitrogen in the endosperm was first completed at the central part then extended to the peripheral layer. Based on these results, it could be concluded that the increase in the source-sink ratio is not sufficient to improve grain filling in the rice plants. It is also very important to maintain the physiological activities of leaves and roots until the later stages of ripening when the inferior spikelets continue to accumulate materials.

【 授权许可】

Unknown