Abstract: Based on the investigation of gap and non-gap stands in the midsubtropical evergreen broad-leaved forest in Wanmulin Nature Reserve of Fujian Province,this paper studied the changes of species diversity in gap gradient and in gaps with different sizes.The results showed that the species richness and diversity decreased gradually from gap center to nongap,ecological dominance was higher in center and lower in edges,and species evenness was in adverse to ecological dominance.The species diversity in all areas of gap was the maximum when the gap size was 200～300 m².

Key words: Wheat seedlings, Zn, Cd, Element uptake