[Effects of light intensity on morphological and physiological characteristics of tobacco seedlings].

Through shading with white gauze to simulate different light habitats (100%, 68.2% 35.4% and 16.7% of full sunlight), this paper studied the effects of light intensity on the morphological and physiological characteristics of tobacco seedlings. The results showed that with the decrease of relative light intensity, seedling height increased, while stem circumference, dry weight/fresh weight ratio, leaf thickness, specific leaf weight, and matter accumulation decreased. Less effect of light intensity was observed on the number of seedling leaves. Under weak light condition, the contents of free water, chlorophyll, total nitrogen, and protein in leaves increased, while bound water content, chlorophyll a/b ratio, and invertase activity decreased. The root/shoot ratio, root biomass, and root vitality also decreased. All of these suggested that weak light was unfavorable to the cultivation of strong tobacco seedlings, and the light conditions of seedbed should be improved in tobacco production.