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以不同强度UV-B照射3年生盆栽柑橘,研究柑橘的光合色素含量、净光合速率和叶绿素荧光特性对UV-B胁迫下的动态响应.结果表明:各处理Fm值显著下降,其中U5的Fm值下降幅度最大.除CK外,各处理Fo均上升.Fv/Fm,Fv/Fo值较UV-B辐射前显著下降,且随辐射时间的增长而降低.各处理QN的值均上升,其中U5上升65.7%.U5处理的QP较辐射前下降了,其它处理QP值均有所上升.随着UV-B辐射时间的增加,Yield,ETR,PSⅡ值逐步降低.且UV-B辐射25d后,各处理Yield,ETR,PSⅡ值最低,到30d时有所回升;UV-B胁迫30d后,对照组CK与U1的净光合速率Pn具有显著性差异,U5净光合速率最低.UV-B对各处理胞间二氧化碳浓度影响不大.各处理之间的气孔导度及蒸腾速率无显著差异,且U1的气孔导度和蒸腾速率都较其他处理高;随着UV-B辐射时间的增长,柑橘叶片中的Ca2+-ATPase活性明显升高.在轻度UV-B辐射下,柑橘能够通过自身的一些抗性机制及一些生理反应来抵御胁迫,但在强UV-B辐射下U5光合系统及细胞膜等受到一定程度的伤害,难以恢复到相应水平.
The dynamic response of photosynthetic pigment content, net photosynthetic rate and chlorophyll fluorescence of Citrus under UV-B stress was studied under different intensity of UV-B irradiation.The results showed that the Fm value of each treatment decreased significantly, among which Fm The values of Fv / Fm and Fv / Fo decreased significantly compared with that before UV-B radiation and decreased with the increase of radiation time.The values of QN increased U5 increased by 65.7% .The QP of U5 decreased compared with that before radiation, while QP of other treatments increased.With the increase of UV-B irradiation, the values of Yield, ETR and PSⅡdecreased gradually.After 25 days of UV-B radiation , And the lowest values of Yield, ETR and PSⅡ in all treatments increased after 30 days. After 30 days of UV-B stress, the net photosynthetic rate Pn of CK and U1 were significantly different and the net photosynthetic rate of U5 was the lowest. There was no significant difference in the intercellular CO2 concentration between treatments.The stomatal conductance and transpiration rate were not significantly different among treatments, and the stomatal conductance and transpiration rate of U1 were higher than those of other treatments. With the increase of UV-B radiation time, Citrus leaves in the Ca2 + -ATPase activity was significantly increased under mild UV-B radiation, citrus through some of their own resistance Sexual mechanism and some physiological responses to stress, U5 photosynthetic system and cell membrane were harmed to a certain degree under strong UV-B radiation and it was hard to recover to the corresponding level.