自然条件下滤减UV-B辐射对烤烟光合色素含量的影响

在自然环境中，以烟草栽培品种K326为材料，通过覆盖不同透明薄膜滤减UV—B辐射，研究100％（CK）、75％（T1）、50％（T2）、35％（T3）UV—B辐射透过率处理下，不同强度UV—B辐射对烟草光合色素含量的影响。结果表明：烤烟三类光合色素对UV—B辐射有不同响应。类胡萝卜素对UV—B辐射响应较敏感。成熟初期，类胡萝卜素含量与UV—B辐射强度变化具有较好的正相关性，而chl a和chl b含量基本与UV—B辐射强度呈反向变化关系。成熟后期，由于UV—B辐射累积效应，光合色素含量变化没有明显规律。现蕾期至成熟采烤烟初期，chl a：chl b与UV—B辐射的反向变化关系较明显，后期则无明显规律，其含量的下降与UV—B辐射的累积效应有关。

Effects of Attenuated UV-B Radiation on Dynamic Changes of Photosynthetic Pigment Contents in Flue-cured Tobacco under Natural Conditions

In the outside field condition,Yunnan flue-cured tobacco variety-K326 was potted under different types of transparent films which were used to reduce solar UV-B radiation,and the UV-B penetration rate was 100%(CK),75%(T1),50%(T2),35%(T3),respectively.The dynamic changes of flue-cured tobacco photosynthetic pigment contents under different radiant intensity of UV-B radiation treatments were studied.The results showed that three kinds of flue-cured tobacco photosynthetic pigment contents had different sensibility to UV-B radiation.Carotenoid was more sensitive to UV-B radiation than other photosynthetic pigments.In the earlier stage of mature,the sensitivity of carotenoid had preferable coherence to UV-B radiation,while the contents of chlorophyll a and chlorophyll b had a counter-relation of change to it,due to the accumulative effect of UV-B radiation,there was no significant change of photosynthetic pigments contents in the late stage of mature.During the earlier period of budding and maturation-baking,the ratio of chlorophyll a and chlorophyll b had a significant counter-relationship to responding UV-B radiation,by contrast,there was no significant difference in the late stage.The downtrend of photosynthetic pigment contents was related to the accumulative effect of solar UV-B radiation.