Abstract: Taking tobacco cultivar K326 as test object, a pot experiment was conducted to study the effects of reduced UV-B radiation on the dynamic changes of the morphology and density of tobacco leaf glandular trichome from flowering to post-technological maturity stage. Four treatments were installed, i.e., natural UV-B radiation (CK), and reduced 25% (T₁), 50% (T₂), and 65% (T₃) of natural UV-B radiation via canopy-covering with different thickness transparent plastic film, and scanning electron microscope was used to observe the dynamic changes. It was first reported that K326 leaf had branched glandular trichome. The glandular trichome on adaxial epidermis was sensitive to UV-B radiation at the stages of flowering, physiological maturity, and pre-technological maturity, while that on abaxial epidermis was sensitive to UV-B radiation at the stages of flowering and posttechnological maturity. Treatment T₃ caused the lower density of glandular trichome and delayed its development, while treatments T₁ and T₂ induced the higher density of glandular trichome and its secondary development at technological maturity stage. In all treatments, long stalk glandular trichome was the dominant, and its density on abaxial epidermis was higher than that on adaxial epidermis except in treatment T₃, in which, the glandular trichome density on the two epidermises was almost the same. Reduced UV-B radiation was conducive to the development of long stalk glandular trichome on abaxial epidermis. Trichome type, which induced the secondary development, varied with treatments and growth stages. Our results indicated that a certain higher intensity of UV-B radiation played an important role in promoting the development of glandular trichome on tobacco leaf, and in the experimental field, reduced 25%-50% of UV-B radiation was suitable for the development of the glandular trichome.

Key words: Bailong River forest region, Forest resource, Sustainable development capacity, Degree of harmony