Abstract: An in situ field experiment was conducted in Yuanyang terraced fields to study the effects of simulated enhanced UV-B radiation at different intensity levels (0, 2.5, 5.0, and 7.5 kJ·m^-2) on the leaf morphology and anatomical structure of two local rice cultivars, Yuelianggu and Baijiaolaojing, at tillering, jointing, and booting stages. For the two test rice cultivars, enhanced UV-B radiation induced a gradual decrease of leaf length, leaf width, and single leaf area, a significant increase of leaf thickness and upper and lower epidermal cuticle thickness, an increase of upper epidermal thickness, and a significant decrease of lower epidermis thickness. Enhanced UV-B radiation also induced a loose array of mesophyll cell and an increase of intercellular space. Under 5.0 and 7.5 kJ·m^-2 of UV-B radiation, the thickness of lower epidermal cuticle of Baijiaolaojing was significantly bigger than that of Yuelianggu, but no significant difference was observed under other UV-B radiation intensity levels. The leaf length and the thickness of upper epidermal and lower epidermal cuticle of the two test cultivars under 5.0 and 7.5 kJ·m^-2 of UV-B radiation, and the leaf area and the thickness of upper epidermal cuticle of Baijiaolaojing under 7.5 kJ·m^-2 of UV-B radiation were significantly larger than those under 2.5 kJ·m^-2 of UV-B radiation, but no significant differences were observed between other treatments. These results indicated that enhanced UV-B radiation had significant effects on the leaf morphology and anatomical structure of local rice cultivars in Yuanyang terraced fields.

Key words: Vigna angularis, shading, photosynthetic characteristics, photosynthetic pigment, growth, yield.