Abstract: With shading experiment, this paper studied the seed germination and seedling early growth of Shorea wantianshuea, a representative species in Xishuangbanna seasonal rain forest under different light intensity and forest habitat. The results showed that both 100% light and deepest shading did not facilitate the germination of S. wantianshuea seed, while medium shading accelerated the seed germination. Gap center was more appropriate to the seed germination than gap edge and under-canopy. The seeds in gap center had the highest germination rate and rapid germination. Under partially shading, the seedling height, diameter of basal stem, and leaf area per seedling were in their peak, while the root-shoot ratio decreased with increasing shading and achieved its maximum under 100% light. The specific leaf area increased with increasing shading in a certain range, and peaked under 42% light. Gap center was beneficial to the early seedling growth, with all growth parameters except rootshoot ratio peaked there. The effects of environmental factors, mainly light intensity and quality, on the seed germination and seedling growth of S. wantianshuea were discussed.

Key words: Rice(Oryza sativa L), Grain weight, Developmental genetics, Heterosis, Genetic relation