Amendment of environment by plant : Response of plant to elevated CO_2 Concentration

植物对环境的改善：植物对CO_2浓度升高的反应

• 批准号: 11660063
• 负责人: FUJITA Kounosuke
• 金额: $ 0.38万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11660063/
• 关键词: Soybean; CO_2 enrichment; ^<13>C; ^<15>N; Nitrate; pod removal; partitioning; sink; 高CO_2濃度; 転流率; 分配率; 蒸散速度; 夜間

For protection and amendment of environment by plant, the response of soybean to elevated CO_2 concentration was examined in terms of translocation of photosynthate and nitrogenous assimilates. Soybean (Glycine max cv. Tamahomare or Greenhormer) was exposed to CO_2 concentration (35 and 100 Pa CO_2) for 17-21 days at the grain filling stages under controlled glasshouse conditions. In the experiment 1, nitrate concentration in the culture media was changed, and in the experiment 2, pod removal treatment was also applied.Experiment 1, Effect of CO_2 concentration and nitrate levels on nitrate reduction, distribution of nitrogenous assimilate : (1) While CO_2 enrichment significantly increased reduced-N amount in the whole plant under the presence of nitrate in the culture media, such effect was not observed without application of nitrate. (2) Nitrate reductase activity in leaves increased after imposed to elevated CO_2 concentration. (3) More ^<15>N fed from a terminal leaflet of an upper leaf was exported by CO_2 enrichment. Experiment 2, Effect of CO_2 concentration and pod removal on partitioning of ^<13>C and ^<15>N : (1) The elevated CO_2 concentration led to enhancement of plant growth. (2) The elevated CO_2 concentration decreased export of both ^<13>C and ^<15>N, and the decrease was more pronounced in the latter. (3) While ^<15>N atom % excess and concentration in various amino acids in leaf petioles and stem was not affected by CO_2 enrichment, these values in asparagine as well as proline were increased by pod removal. This suggests that some nitogenous compounds are assimilated in petioles and stem when sink activity is limited. The current study suggest that CO_2 enrichment affects not only carbon metabolism but also nitrogen metabolism in plant.

从光合产物和氮同化物运转的角度研究了大豆对CO_2浓度升高的反应，以期为植物保护和改善环境提供理论依据。大豆（Glycine max cv. Tamahomare或Greenhormer）在温室条件下于灌浆期暴露于CO_2浓度（35和100 Pa CO_2）17-21天。试验1改变培养液中硝酸盐浓度，试验2进行脱荚处理。试验1，CO_2浓度和硝酸盐水平对硝酸盐还原、氮同化物分配的影响：（1）在硝酸盐存在的条件下，CO_2加富显著增加了植株的还原态氮含量，在不施用硝酸盐的情况下没有观察到这种效果。(2)CO_2浓度升高后，叶片硝酸还原酶活性增加。(3)CO_2<15>浓度升高使上部叶片的顶生小叶输出更多的^ N。试验二，CO_2浓度和荚果去除对氮、碳分配的影响<13><15>：（1）CO_2浓度升高促进了植物生长。(2)CO_2浓度的升高使^<13>C和^<15>N的输出均减少，且^N的减少更为明显。(3)CO_2浓度升高对<15>叶柄和茎中的N原子过剩率和各种氨基酸含量没有影响，而去除荚果使天冬酰胺和脯氨酸含量增加。这表明，当库活性受到限制时，一些氮源化合物在叶柄和茎中被同化。目前的研究表明，CO_2浓度升高不仅影响植物的碳代谢，也影响氮代谢。