| Taking "Siji Cucurmber","Baoza No.2","Cuibao No.2","Fruit Cucumber" and "Jinchun No.5" 5 cucumber varieties as test materials,Through greenhouse high temperature treated, CO2 enrichment and increased humidity, Researched effects on the photosynthetic efficiency of greenhouse cucumber and trends and differences of index of heat torlerance on five varieties of cucumber .Experiment results show :Noon daily average of 40℃~50℃for more 4 hours , The photosynthetic rate of leaf of greenhouse cucumber significantly higher than that of the control of conventional management which having no CO2 enrichment. Even at noon , the photosynthetic rate of the high temperature treatment area was significantly higher than the control. That was to say,greenhouse cucumber "Midday-depress" phenomenon was connected with CO2 concentration of the environment. High temperature treatment mainly accumulated leaves photosynthetic product-starch, through respiration decomposition out, avoided the poison of the chloroplast starch accumulation. At the beginning of the high temperature treatment, chlorophyll content of greenhouse cucumber would decrease,But after about a week later, it would be able to resume soon.After high temperature treated, Contents of SOD,MDA and proline of all cucumber varieties trended to go higher than controls,While content of proline trended to go lower than controls.Through the index of the heat torlerance of cucumber and the actual growth of the field, we can see the " Siji Cucurmber "," Jinchun No.5" were the most heat torlerance, "Baoza No.2", "Cuibao No.2" followed by heat resistance, "Fruit cucumber," the worst heat torlerance. |
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