高温强光胁迫对西葫芦幼苗光合生理特性及荧光参数的影响

Effects of high temperature and strong light stress on photosynthetic,physiological characteristics and fluorescence parameters of squash seedlings

研究高温强光交叉胁迫对西葫芦幼苗光合生理特性和荧光参数的影响。结果表明:高温强光下西葫芦幼苗的光合速率(Pn)和气孔导度(Gs)均显著低于适宜温光处理。处理28 d后,高温强光处理的胞间CO2浓度(Ci)显著高于适宜温光处理,而蒸腾速率(Tr)则显著低于正常温光处理。另外,高温强光下叶片的等离子体源离子注入(PSⅡ)技术最大光化学效率(Fv/Fm)、PSⅡ实际光化学效率(ΦPSⅡ)、开放PSⅡ中心激发能捕获效率(Fv′/Fm′)和光化学猝灭系数(qP)和叶绿素含量均不同程度的低于适宜温光处理,而NPQ和丙二醛含量却显著升高,细胞膜透性增大。

The responses of photosynthetic and physiological characteristics, fluorescence parameters of squash seedlings under high-temperature and strong light cross stress were studied. The resnlts showed that photosynthetic rate （Pn）, stoma conductance （G^8） of squash seedlings under high-temperature and strong light were lower significantly than those under normal temperature-light condition. And CO2 concentration in cell spaces （Ci） of squash seedlings under high- temperature and strong light increased significantly after 28 d, however transpiration rate （Tr） decreased significantly. In addition, maximal PS Ⅱ efficiency （Fv/Fm）, actual PSII efficiency （∮esn）, efficiency of excitation energy capture by open PSI[ reaction centre（Fv′/Fm′） and photochemical queehing coefficient （qp） of squash seedlings decreased under hightemperature and strong light, whereas NPQ, MDA and membrane permeability increased significantly.