Effects of a Reduction in Soil Moisture from One Month beforeFlowering through Ripening on Dry Matter Production and Ecophysiological Characteristics of Wheat Plants
Effects of a Reduction in Soil Moisture from One Month beforeFlowering through Ripening on Dry Matter Production and Ecophysiological Characteristics of Wheat Plants
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DOI：
10.1626/pps.7.143
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发表时间：
2004-01
影响因子：
2.5
通讯作者：
K. Nakagami;T. Ookawa;T. Hirasawa
中科院分区：
文献类型：
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作者：
K. Nakagami;T. Ookawa;T. Hirasawa
摘要我们在之前的研究中发现，在相对较低土壤水分条件下生长的小麦植株（D图）比在当地平均降水量基础上浇水的植株（W图）获得的干物质更重。本研究旨在详细分析不同土壤水分条件下导致W和D样地植物干物质生产差异的生理生态特征。在W图中，30 cm深处的土壤基质势保持在−4 kPa左右。在D区，抽穗前1个月和抽穗期浇水后，压力逐渐下降，抽穗期和中熟期分别达到-80 kPa左右。D区的植物比W区的植物产生更重的干物质和更发达的根系。D区较高的净同化率和较大的叶面积是作物生长速率较高的原因，这是由于D区既避免了水分胁迫对光合速率和叶片展开的抑制，又在叶片衰老过程中保持了较高的光合速率和较大的叶面积。D区植株在开花期积累的氮量大于W区，衰老期叶片的氮含量也高于W区。D区植物木质部汁液中细胞分裂素活性较高。这些特点可能有助于延迟在叶片衰老过程中的光合速率和叶面积的下降，并似乎支持水分限制条件下的根系的增强发展。
Abstract We found in the previous study that the wheat plants grown under relatively low soil moisture conditions (D plot) could attain heavier dry matter than the plants watered on the basis of average local precipitation (W plot). The aim of this study was to make a detail analysis of the ecophysiological characteristics that cause the difference in dry matter production between the plants in the W and D plots under different soil moisture conditions. Soil matric potential at a depth of 30 cm was kept at about −4 kPa in the W plot. It decreased gradually after watering at about one month before heading and at heading, reaching about −80 kPa at heading stage and at the mid-ripening stage respectively, in the D plot. The plants in the D plot produced heavier dry matter and a better developed root system than the plants in the W plot. The higher net assimilation rate and larger leaf area, which accounted for the higher crop growth rate of the D plot, weredue both to avoiding suppression of the photosynthetic rate and leaf expansion owing to water stress, and to maintaining high rates of leaf photosynthesis and a large leaf area during leaf senescence. A larger amount of nitrogen was accumulatedat the flowering stage and the nitrogen content of leaves remained higher during senescence in plants in the D plot than those in the W plot. The activity of cytokinins in the xylem sap was higher in plants in the D plot. These characteristics might have contributed to the delay in the decline in the rate of photosynthesis and in leaf area during leaf senescence and seemed to be supported by the enhanced development of the root system under moisture-restricted conditions.