开花期土壤短期干旱和复水对大豆光合作用和产量的影响

以大豆(Glycine max)为材料, 研究开花期土壤水分变动对叶片光合生理以及产量形成的影响, 以期为大豆的节水栽培和水分高效利用提供理论依据。研究发现, 大豆叶片气孔导度(Gs)对土壤水分的匮缺更加敏感。干旱胁迫降低了叶片的净光合速率(Pn), 但复水后, 叶片水势和净光合速率等在实验过程中都可以得到迅速恢复, 并且蒸腾速率(Tr)、气孔导度和胞间CO₂浓度(Ci)在复水后的第3 天与对照相比显著提高, 表现出一定的超补偿效应。研究发现, 在开花期即使短期的土壤干旱, 也会对大豆后期的生物量及其分配产生较大的影响, 开花期干旱和复水, 显著降低了大豆叶片和茎的生物量, 使根茎比提高16.7% (P<0.05), 收获指数增加26.3%(P<0.05)。

Effect of Short-term Drought and Rewatering During the Blooming Stage on Soybean Photosynthesis and Yield

To investigate the water-saving cultivation and water-efficiency use of soybean, we selected a soybean variety widely cultivated in Henan province, China — Glycine max ‘zheng92116’ — to determine the effect of short-term soil drought and rewatering during the blooming stage on soybean leaf photosynthesis and yield. As compared with leaf water content, stomatal conductance (Gs) was more sensitive to soil water deficiency . At 2 days after water was withheld, when the soil relative water content dropped to 27.2%, Gs and net photosynthetic rate (Pn) decreased to 54.1% and 81.1%, respectively, in experimental leaves, but the leaf water potential did not differ from control leaves. After rewatering, leaf water potential and Pn recovered quickly; transpiration rate (Tr), Gs and intercellular CO2 concentration (Ci) of the treatment group were significantly higher than those of the control group 3 days after rewatering, which showed a super-compensation effect. The drought treatment led to a significant decrease in leaf and stem biomass of soybean, which resulted in a 16.7% increase in ratio of root to shoot and a 26.3% increase in harvest index. The results suggested that short-term drought at the blooming stage could significantly influence soybean yield and biomass.