水分胁迫和气象因子对冬小麦生理特性的影响

通过对防雨棚下测坑中种植的冬小麦设置不同的土壤水分控制下限指标,研究了土壤水分状况及气象因子对冬小麦生理特性的影响,分析了不同生理指标的日变化规律,建立了几种生理指标与环境因子间的逐步回归关系式。研究结果表明,各生理指标受环境因子的影响有着明显的日变化特征,不同处理气孔导度(Gs)峰值出现的时间早于光合速率(Pn),而蒸腾速率(Tr)峰值出现的时间滞后于光合速率,随着土壤水分胁迫程度的增加,Gs、Tr、Pn的峰值有提前的趋势;不同土壤水分条件下水分胁迫指数(CWSI)和冠气温差的峰值均在13:00左右出现,而细胞液浓度(CSC)的最大值出现在14:00～15:00。土壤水分与Tr、Pn、Gs呈极显著正相关,而与CWSI、冠气温差和CSC呈极显著负相关。此外,气象因素对冬小麦生理指标的影响程度会随着土壤水分状况而发生变化,生理指标与环境因子的逐步回归结果表明,土壤水分和光合有效辐射是影响冬小麦生理指标最主要的环境因子。

Effects of Water Stress and Weather Factors on Physiological Characteristics of Winter Wheat

By imposing different lower limits of soil moisture on winter wheat(Triticum aestivum L.) grown in non-weighing lysimeters under a rain shelter, the effects of soil water status and meteorological factors on physiological characteristics of winter wheat were studied, the diurnal variation patterns of physiological indices and the regression equations between physiological indices and environmental factors were established. The results showed that each physiological index had obviously diurnal change characteristics due to the influence of environmental factors, the time when the maximum of stomatal conductance (Gs) appeared was earlier than that of photosynthetic rate (Pn), and the time when the peak value of transpiration rate (Tr) emerged was later than that of Pn. The maximum of Gs, Tr and Pn appeared to be earlier with decrease in soil moisture. The maximum crop water stress index (CWSI) and canopy-air temperature difference (Tc-Ta) under different soil moisture occurred at 13:00 pm and the peak value of cell sap concentration (CSC) appeared at 14:00-15:00 pm. In addition, the correlations between meteorological factors and physiological indices of winter wheat changed with soil moisture. The stepping regression of physiological indices and environmental factors indicated that soil moisture and photosynthetically active radiation (PAR) were mostly important environmental factors affecting the physiological characteristics of winter wheat.