不同光质条件下烤烟叶片衰老的生理效应研究

Physiology Effects of Light Quality on Leaf Senescence in Flue-cured Tobacco Leaves

为探究不同光质对烤烟叶片衰老的作用及其机制,以‘云烟87’为供试材料,自然光为对照,在大田条件下通过覆盖不同颜色滤膜获得不同光质,研究红光(R)、白光(W)、蓝光(B)、紫光(P)、黄光(Y)等不同光质对烤烟成熟衰老过程中质体色素代谢和抗氧化酶活性的调控效应。结果表明,打顶后烟叶中质体色素降解转化,与自然光相比,红光和白光延缓了叶绿素含量的下降,白光和蓝光抑制类胡萝卜素的降解,整个降解过程中各不同光质处理下色素降解率从大到小依次为:蓝光>黄光>紫光>红光>白光>对照。叶片抗氧化酶活性呈先升后降的趋势,黄光和红光诱导了抗氧化酶活性的上升,并且使MDA的含量保持相对较低的水平,从而延缓叶片的衰老。紫光和蓝光则抑制了抗氧化酶的活性,导致叶片MDA含量的持续上升,加速了叶片的衰老进程。由此推测,红光有利于质体色素的合成,蓝光处理对质体色素的降解有促进作用,黄光和红光可使烤烟叶片维持较高的抗氧化酶水平,有利于延缓叶片的衰老。

To investigate the mechanism involved in the different responses of flue-cured tobacco leaf senescence to light qualities, the interaction effects of different lights on plestid pigment metabolism and activities of antioxidant enzymes in the maturation of flue-cured tobacco leaves were investigated. Taking Yunyan 87 （ Ntcotiana tobacum L. ） as test material, by covering red, white, blue, yellow and purple polyethylene films above tobacco plants to obtain different light quality. Results indicated that plastid pigments were degradating and translating after topping. Compared with natural light, red and white light significantly inhibited the degradation of chlorophyll. White and blue light inhibited the degradation of carotenieds. Sequence of pigment degradation rate under different lights during declined stage was blue 〉 yellow 〉 purple 〉 red 〉 white 〉 nature light. The activities of antioxidant enzymes in leaves demonstrated the trend of increased first and then decreased. Yellow and red light increased the activities of antioxidant enzymes, and made the content of MDA at a relatively low level, In contrast, purple and blue light decreased the activities of antioxidant enzymes and led to higher contents of MDA in the leaves. In summary, red light treatment contributed to accumulation, and blue light treatment contributed to degradation. Yellow and red light could maintain high levels of antioxidant enzymes and delay aging of flue-cured tobacco leaves.