关键词: 光质, 烤烟, 内源激素, 膜脂过氧化, 衰老, 烟叶品质

Abstract: In order to investigate the effects of different light qualities on flue-cured tobacco aging process and flue-cured tobacco leaf guality, this paper studied the effects of 5 different light qualities including white(W), red(R), yellow (Y), blue(B) and purple(P) under field condition by covering different color polyethylene films above tobacco plants, on endogenous hormones, membrane lipid peroxidation in the maturation of flue-cured tobacco leaves taking ‘Yunyan87’ as experimental material. The results indicated that compared with white light (the control), red light could significantly increase the contents of cytokinin (CTK) and gibberellin (GA), while reduced abscisic acid (ABA)  content effectively. Blue light and purple light went against the raising of CTK content, but increased ABA content in tobacco leaves. The auxin (IAA) content decline under blue light and purple light treatments was earlier than that under red light and yellow light treatment. Red light and yellow light could increase catalase (CAT) activity and decreased hydrogen peroxide (H2O2) content during flue-cured leaf aging process, and thus maintained the malondiadehyde (MDA) content at a relatively low level, and slowed down the plant aging process. Blue light and purple light treatments decreased CAT activity  and made H2O2 and MDA contents higher than the contrast and other treatments, thus speeded up the plant aging process. Red light treatment increased the total sugar content, shmuck value and ratio of potassium and chlorine; yellow light treatment increased the contents of total nitrogen and nicotine; red light and yellow light treatments reduced the  protein content and ratio of sugar and nicotine. In general,  the contents of IAA, CTK and GA of tobacco leaves and CAT activity were increased, whereas the contents of H2O2, MDA and ABA were reduced under red light treatment. The aging of flue-cured tobacco leaves was delaied, thus the quality of tobacco leaves was improved.

Key words: light quality, flue-cured tobacco, endogenous hormone, membrance lipid peroxidation, senescence, quality of tobacco leaf