| Grain filling stage is the key period for wheat kernel weight. However,wheat often encounters high light intensity combined with high temperature at this stage. The combined stresses result in the decline of photosynthetic rate,which ultimately causes yield loss. In our previous study,we found that a wheat variety Zhengmai 7698 showed strong tolerance to high light intensity and high temperature. In order to illuminate the physiological mechanism of high light intensity and high temperature co-stress tolerance of Zhengmai 7698,we took two wheat varieties (Zhoumai 18 and Aikang 58) as control,to study their physiological characters under three treatments (high light,HL; high temperature,HT; and high light and high temperature,HLHT). The results showed that the degree of negative effects on wheat photosynthesis was HLPn),transpiration rate (Tr),stomatal conductance (Gs),maximum photochemical efficiency (Fv/Fm) and photochemical quenching (qP) in Zhengmai 7698 were lower than that in Zhoumai 18 and Aikang 58,and the increased degree of superoxide anion production rate,content of H2O2 and malondialdehyde,relative electrical conductivity in Zhengmai 7698 were also lower than that in Zhoumai 18 and Aikang 58,whereas the increment of superoxide dismutase,peroxidase and catalase activity were significantly higher than that in Zhoumai 18 and Aikang 58.Therefore,we concluded that Zhengmai 7698 had better tolerance to HL,HT,and HLHT stresses than Zhoumai 18 and Aikang 58. It has higher antioxidant enzyme activities under abiotic stress,reducing the damage degree to its photosynthetic apparatus,and keeping high level of photosynthetic efficiency,which is the reason for its good tolerance to abiotic stress. |
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