高温胁迫对设施番茄和黄瓜光合特性及抗氧化酶活性的影响

以黄瓜品种"津优35"和番茄品种"金粉2号"为试材,于2011年1～6月在南京信息工程大学人工气候箱进行环境控制试验,系统研究高温32～40℃处理不同时间对黄瓜、番茄叶片光合特性及抗氧化酶活性的影响。结果表明:高温胁迫处理明显抑制了黄瓜和番茄光合速率,处理时间越长,光合速率下降越快,当38～40℃高温持续一段时间后,黄瓜、番茄的最大光合速率为负值;随高温胁迫程度的增加和胁迫时间的延长,黄瓜和番茄的PSII潜在光化学效率(Fv/Fm)、光化学淬灭(qP)均呈现下降趋势,40℃高温胁迫5d后再经过恢复,黄瓜和番茄的Fv/Fm及qP无法恢复到对照水平;当温度达到38℃以上时,黄瓜和番茄的SOD、POD、CAT、MDA酶随着胁迫温度的升高和持续时间的增加而呈现与38℃以下时相反的情况,根据高温对黄瓜和番茄叶片光合参数的影响将高温胁迫划分为轻度胁迫、中度胁迫、重度胁迫和极重度胁迫4个等级,并确定气象指标。

Effect of High Temperature on the Photosynthetic Characteristics and Antioxidant Enzyme Activities of Cucumber and Tomato in Greenhouse

The cucumber ’Jinyou 35’ and the tomato ’Jinfen No.2’ were used as materials,the environmental control test was conducted in artificial climate chamber,Nanjing university of information science and technology from January to June,2011.The effects of high temperature 32-40℃ with different time on leaf photosynthetic characteristics and antioxidant enzyme activity of cucumber,tomato were systematically studied,the results showed that the heat stress treatment significantly inhibited the photosynthetic rate of cucumber and tomato,with the processing time longer,photosynthetic rate decreased faster,when 38℃ or 40℃ sustained some hours,the maximum photosynthetic rate of cucumber and tomato was negative;with the levels of heat stress increasing and stress time lengthening,the PSII potential photochemical efficiency(Fv/Fm)of cucumber,tomato,photochemical quenching(qP) showed a downward trend,plants treated by 40℃,after recovering 5 days,Fv/Fm and qP values of cucumber and tomato were still in decline;when the temperature reached above 38℃,the SOD,POD,CAT,MDA of tomato and cucumber was in contrast to the case of the temperature under 38℃.According to the effects of high temperature on photosynthetic parameters of cucumber and tomato leaf,dividing heat stress into four grades: mild stress,moderate stress,severe stress,extremely severe stress,and ascertaining meteorological index.