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通过开展干热风气象条件人工模拟,分别在冬小麦灌浆前期和中期进行重度、轻度及无干热风的平行对比试验。结果表明:干热风对冬小麦生理机能的危害为灌浆中期>灌浆前期,重度干热风>轻度干热风;灌浆中期重度干热风灾害后第2天,小麦旗叶净光合速率(Pn)降低了19.4%~36.6%,蒸腾速率(Tr)降低44.1%~58.0%,气孔导度(Co)降低24.3%~41.7%;其次为灌浆中期轻度干热风,上述各项指标分别减少9.7%~20.2%、28.2%~34.0%和19.9%~31.8%;小麦叶绿素含量(SPAD)和根系伤流量(Gn)也在灌浆中期重度灾害胁迫下降低程度最大,灌浆前期轻度干热风对小麦的胁迫作用不明显;灌浆前期遇干热风天气小麦净光合速率(Pn)和SPAD可在一定程度内修复,其他大部分时段受损的生理机能不可修复。在气孔导度Co>0.1 mmol·m-2·s-1条件下,干热风灾害对Tr的胁迫程度大于Pn。
Through the artificial simulation of the dry and hot wind meteorological conditions, the parallel and comparative experiments of severe, mild and no-dry-hot winds were carried out in the early and middle stages of winter wheat filling respectively. The results showed that dry-hot wind had the most harmful effects on the physiological function of winter wheat in the early filling stage and severe dry-hot air in the early filling stage, while mild dry-hot wind in the early filling stage. The net photosynthetic rate (Pn) of wheat flag leaves decreased by 19.4 (36% -36.6%). The transpiration rate (Tr) decreased by 44.1% -58.0% and the stomatal conductance decreased by 24.3% -41.7%, followed by the mild dry-hot wind during the middle filling stage. , 28.2% -34.0% and 19.9% -31.8%, respectively. The SPAD and Gn of wheat also decreased most under severe stress during mid-filling period. The stress of wheat with mild dry-hot air during the early filling stage was not significantly affected The net photosynthetic rate (Pn) and SPAD of wheat in the case of dry and hot wind in the early filling stage were repaired to a certain extent, while the physiological functions damaged most of the rest of the time could not be repaired. Under stomatal conductance Co> 0.1 mmol · m-2 · s-1, Tr stress was greater than Pn under dry-hot wind disasters.