关键词: 荔枝, 环剥, 遮荫, 光合作用, 枝梢生长

Abstract: In this study，adaptability of litchi to shading as well as the interaction effects of girdling and shading were examined using 12-year-old‘Heiye’litchi（Litchi chinensis Sonn.‘Heiye’）trees. Within the same tree，shoots were treated with girdling，shading and their combination with ungirdled and exposed shoots as the control. Shoot length，leaf gas exchange and chlorophyll fluorescence were measured at determined dates after the treatments. The results showed that the shoot growth and leaf photosynthesis were significantly inhibited by both shading and girdling treatments，while the mechanisms of photosynthesis inhibition of these two treatments seemed different. Girdling treatment significantly lowered leaf chlorophyll content as well as photosynthetic rate with the occurrence of chronic photoinhibition，an indicator of photosystemⅡ（PSⅡ）damage. In shading treatment，F_v/F_m maintained normal but shaded leaves had a lower photosynthetic rate measured even with the same artificial light compared with the control. The reduction of photosynthesis was therefore chiefly due to the impairment of dark reaction. Interestingly，shading significantly alleviated damage on light reaction system caused by girdling.

Key words: litchi, girdling, shading, photosynthesis, shoot growth