低温胁迫对返青期苜蓿叶片荧光参数的影响

摘要

In order to reveal the influence of low temperature in spring on alfalfa in returning green period, using the controlled temperature to simulate the low temperature in spring, the room temperature (25℃)as the control, the changes of chlorophyll fluorescence parameters of alfalfa in returning green period treated at -5℃ for 4h, -5℃ for 12h, -6. 5℃ for 8h and -8℃ for 4h were studied. The results showed that after slight cryogenic stress, the chlorophyll fluorescence parameters of alfalfa leaves did not have significant difference; but at the -6. 5℃ for 8h and -8℃ for 4h, the Fm, Fv/Fm, Fv/Fo decreased, and the lower the temperature,the more the chlorophyll fluorescence parameters changed. It indicated that photo inhibition happened in alfalfa leaves at lower temperature, and the changes of chlorophyll fluorescence parameters were closely related with cold resistance.%为了揭示春季低温对返青期苜蓿叶片光抑制的影响,采用人工控温的方法,以苜蓿适宜生长温度(25℃)为对照,研究了返青期苜蓿叶片在-5℃处理4h、-5℃处理12h、-6.5℃处理8h和-8℃处理4h条件下叶绿素荧光参数的变化.结果表明:苜蓿叶片的叶绿素荧光参数值在25℃和-5℃处理4h、-5℃处理12h条件下差异不显著,无明显光抑制发生；但在-6.5℃处理8h和-8℃处理4h条件下,叶绿素荧光参数Fm、Fv/Fm、Fv/Fo和对照相比都明显下降,且温度越低各叶绿素荧光参数值的变化幅度越大.由此表明:低温下苜蓿叶片不同程度发生光抑制,且苜蓿各荧光参数的变化与抗寒性密切相关.