Two soybean (Glycine max) varieties Xudou 18 (waterlogging-sensitive) and Nannong 1138-2 (waterlogging-tolerant) were used to study the regulation effect of spraying sodium diethyldithiocarbamate (DDTC) on photosynthetic indexes, activities of sucrose-metabolizing enzymes of leaves and contents of carbohydrates in leaves, roots and nodules. The results showed that waterlogging stress resulted in an obvious decrease in shoot dry weight, root dry weight and nodule dry weight of soybean plants, net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr) of leaves, starch content of roots and sucrose and starch contents of nodules. Nannong 1138-2 had smaller decrease in plant dry weight, gas exchange parameters and starch content of roots than Xudou 18, while there was a similar change in sucrose and starch contents of nodules between two varieties. Conversely, waterlogging stress significantly increased sucrose phosphate synthetase (SPS), sucrose synthetase (SS) (synthesis), SS (cleavage), acid invertase (AI) activities and solube sugars, sucrose and starch contents of leaves and solube sugars and sucrose contents of roots. Nannong1138-2 exhibited smaller increase in activities of SS (cleavage), AI and concentrations of solube sugars, sucrose and starch of leaves, but a greater increase in SPS and SS (synthesis) activities of leaves. DDTC treatment increased plant dry weight of two varieties under waterlogging stress, and thus alleviated the growth inhibition of waterlogging stress on soybean plants. DDTC treatment increased gas exchange parameters of leaves, the activities of SPS and SS (synthesis) and decreased the activity of SS (cleavage) of leaves, and further improving the transportation of sucrose from leaves to roots and nodules under waterlogging stress. In addition, DDTC treatment increased soluble sugars, sucrose and starch contents of roots and sucrose and starch contents of nodules, indicating that DDTC treatment played an important role in the regulation of growth and physiological process of carbon metabolism of soybean plants under waterlogging stress.%为了研究二乙基二硫代氨基甲酸钠(DDTC)对大豆碳水化合物代谢的调节作用,为大豆抗渍涝栽培提供技术支持,本研究以渍涝敏感型大豆品种徐豆18和耐渍涝品种南农1138-2为材料,采用盆栽的方式,花期淹水前喷施DDTC,调查大豆叶片光合特性、蔗糖代谢酶活性及叶片、根系和根瘤中碳水化合物含量.结果表明:淹水胁迫降低了植株地上部、根系和根瘤干物重,叶片净光合速率(Pn)、气孔导度(Gs)、胞间二氧化碳浓度(Ci)、蒸腾速率(Tr),根系中淀粉含量、根瘤中蔗糖和淀粉含量.其中,南农1138-2植株干物重,叶片光合气体交换参数以及根系中淀粉含量比徐豆18下降幅度小,而两品种间根瘤中蔗糖和淀粉含量下降幅度基本一致.与之不同,叶片中蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)(合成方向)活性、SS(分解方向)、酸性转化酶(AI)活性,叶片可溶性糖、蔗糖和淀粉含量,根系中可溶性糖、蔗糖含量增加.其中,南农1138-2叶片中蔗糖合成酶(SS)(分解方向)和酸性转化酶(AI)活性、可溶性糖、蔗糖和淀粉含量增幅较小,而叶片中蔗糖磷酸合成酶(SPS)、SS(合成方向)活性增幅较大.DDTC处理提高了淹水胁迫下两品种植株干物重,缓解了淹水胁迫对大豆植株生长的抑制;提高了叶片光合气体交换参数,叶片中SPS和SS(合成方向)活性,并降低了SS(分解方向)和AI活性,促进了淹水胁迫下叶片中蔗糖向根系和根瘤的转运;DDTC处理也增加了根系中可溶性糖、蔗糖和淀粉含量,根瘤中蔗糖和淀粉含量,表明DDTC处理在调控淹水胁迫下大豆植株生长和碳代谢生理过程中起着重要的作用.
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