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Relations between the leaf senescence and the reduction of roof functions in crop plants under water stress

水分胁迫下作物叶片衰老与屋顶功能下降的关系

基本信息

批准号：
09460008
负责人：
HIRASAWA Tadashi
金额：
$ 9.73万
依托单位：
Tokyo University of Agriculture and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09460008/
关键词：
Cytokinin Nitrogen Photosynthesis Root exudation Root function Leaf senescence Soil moisture Water stress トウモロコシ水稲老化 Rubisco 葉の窒素含量出液速度硝酸態チッ素緑色程度

项目摘要

Reduction in leaf photosynthetic rate due to senescence decreases dry matter production and yield. However, the mechanisms of the leaf senescence are not still known. The leaf senescence is enhanced in some environmental conditions. And other organs such as roots are expected to affect leaf senescence. In this research, effects of soil moisture deficiency and root functions on leaf senescence were investigated. The obtained results are as follows.(1) Clear differences in leaf senescence during ripening were observed in soybean plants between cultivars and between plants grown under different soil moisture conditions. The plants, showing a slow leaf senescence, had a well-developed root system and showed a high rate of root exudation.(2) Reductions in soil moisture induced leaf senescence in rice and maize plants. Leaf senescence of rice plants is promoted with a small reduction in soil moisture. However, leaf senescence of a wilting mutant, growing under submerged soil conditions, was … More slower than the wild type, growing under moderately deficient soil moisture conditions, even though the mutant had a greater leaf xylem resistance to water transport and, therefore, a lower midday leaf water potential. The root exudation rate was significantly higher in the former plants than in the latter plants.(3) Reduction in leaf photosynthetic rate due to senescence in ripening stage was large in the rice, cv. Nipponbare compared with cv. Akenohoshi. Total amount of nitrogen and cytokinins transported from root to shoot was estimated to be significantly large in Akenohoshi.(4) Under deficient soil moisture conditions, exudation rate decreased significantly in rice and maize plants. And total amount of nitrogen and cytokinins also decreased in maize plants.(5) From these results, root may affect leaf senescence through the functions of nitrogen uptake and cytokinin synthesis. The reduction in transport of nitrogen and cytokinins may be responsible for the promotion of the senescence under the deficient soil moisture conditions. Less

由于衰老，叶片光合速率降低，干物质产量和产量下降。然而，叶片衰老的机制尚不清楚。在一定的环境条件下，叶片衰老加快。而其他器官，如根，预计会影响叶片的衰老。研究了土壤水分缺乏和根系功能对叶片衰老的影响。所得结果如下：(1)大豆植株成熟过程中叶片衰老在不同品种和不同土壤水分条件下存在明显差异。植株叶片衰老缓慢，根系发育良好，根系渗出率高。(2)土壤水分减少导致水稻和玉米植株叶片衰老。土壤水分的少量减少会促进水稻植株的叶片衰老。然而，在浸没土壤条件下生长的萎蔫突变体的叶片衰老速度比在中度土壤水分不足条件下生长的野生型要慢，尽管该突变体具有更强的叶片木质部对水分输送的抵抗力，因此叶片中午水势较低。前者根系渗出速率显著高于后者。(3)水稻成熟期衰老导致叶片光合速率下降幅度较大，cv。日本与cv比较。Akenohoshi。从根到茎的氮和细胞分裂素运输总量在赤竹草中显著增加。(4)土壤水分不足条件下，水稻和玉米植株的泌水速率显著降低。玉米植株氮素总量和细胞分裂素总量均有所下降。(5)从这些结果来看，根系可能通过氮吸收和细胞分裂素合成的功能影响叶片衰老。氮和细胞分裂素运输的减少可能是土壤水分不足条件下促进衰老的原因。少