灌浆期涝害对小麦旗叶光合特性影响及降渍恢复效应

Effect of Waterlogging on Photosynthetic Characteristics of Wheat Flag Leaves during Grain Filling and Recovery Effect of Water Stress Relief

2015-2016年以小麦品种烟农19为材料,采用盆栽实验研究灌浆期持续6d和9d涝害处理对旗叶光合特性的影响及水分胁迫解除后旗叶光合特性的变化。结果表明:灌浆期涝害会显著降低小麦旗叶的净光合速率(P<0.05),但不同处理下降的幅度存在差异;涝害6d处理(WL6)和涝害9d处理(WL9)净光合速率分别降至正常水分处理(对照,CK)的82.0%和71.5%;水分胁迫解除后3d,WL6处理的净光合速率得到恢复,与CK表现一致,而WL9处理的旗叶净光合速率与CK差异显著,仅恢复至CK的86.3%。涝害阶段及水分胁迫解除后3d,小麦旗叶SPAD值的变化趋势与净光合速率基本保持一致。与涝害9d处理相比,涝害6d处理进行降渍以后,小麦叶片的光合特性能得到较好恢复。涝害期间,WL6处理的旗叶胞间CO2浓度较对照显著升高,表明涝害6d后旗叶净光合速率下降的主要原因是由于非气孔因素所致;WL9处理气孔导度显著下降的同时,胞间CO2浓度却无显著变化,说明涝害9d后小麦叶片的低光合作用主要也是受到了非气孔因素的影响,与叶片气孔的张开程度无关。

In this study, the effects on photosynthetic characteristic of flag leaf under the treatments at 6 days and 9 days during waterlogging and 3 days after relief of water stress were investigated using wheat cultivar Yannong 19 in pot culture both in 2015 and in 2016, respectively. The results showed that the net photosynthetic rate of wheat leaves at the filling stage was significantly reduced by waterlogging with differences in the extent of decline among all the treatments. The net photosynthetic rates (NPRs) of flag leaf after 6 days waterlogging (WL6) and 9 days waterlogging (WL9) were 82.0% and 71.5% of those of control treatment (CK), respectively. The NPRs of flag leaf under WL6 treatment were recovered after the water stress relieved for three days with the consistent performance of CK, while the NPR of flag leaf under WL9 treatment was recovered to 86.3% compared to that of CK with a significant difference. The SPAD values of wheat flag leaf showed a consistent trend with that of the NPR under waterlogging treatment after the water stress was relieved for three days. After the water stress was relieved, the photosynthetic characteristics of WL6 could be recovered better than those of WL9. During waterlogging, the intercellular CO2 concentration of WL6 was significantly higher than that of the control, indicating that the NPR decrease of flag leaf after 6 days of waterlogging was due to non-stomatal factors. While the stomatal conductanceon leave under WL9 treatment decreased significantly, there was no significant change in intercellular CO2 concentration. The results suggested that the low photosynthesis of wheat leaves after waterlogging for 9 days was mainly affected by non-stomatal factors regardless of the stomatal opening.