Effect of Defferent Shading on Growth of Tissue-cultured Hevea Brasiliensis Seedlings

Artificially imposed 0% (CK), 50%, 70%, 80% or 90% shading condition was applied on seedlings of rubber tree (Hevea brasiliensis) to evaluate the effect on growth of the plants in Hainan Province. The results showed that, with 90% shading, the height, stem girth, leaf whorl distance, and leaf count of the seedlings were significantly higher than those of the plants grown under other treatments. As compared to CK, the total area and chlorophyll content of leaves increased as well with the largely shaded condition, but decreased at 50% or 70% level. In addition, 90% shading also rendered the significantly higher transplanting rate, at 91.72%. It appeared that 90% shading blocked much of the natural sunlight and lowered the surrounding temperature to significantly promote the growth and increase the leaf size and chlorophyll content of the tissue-cultured H. brasiliensis seedlings in Hainan Province.