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

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

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)。

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.