Abstract
In order to study the effects of shading on the growth of Torreya nucifera seedlings, two-year old seedlings were grown under different light conditions (artificial-shading) of 100, 52, 46, 14 and 7% in relative light intensity (RLI) for two growing periods. The growth of height and total dry weight of seedlings were promoted under the weakest shading (52% RLI), and were inhibited markedly under the heavy shading (7% RLI). The best growth of basal diameter was observed with both the seedlins grown under the weak shading (52% RLI) and the open (100% RLI), and decreased as RLI declined. These results suggest that Torreya nucifera is a shade-tolerant species. The portion of leaf in total weight of seedlings increased with increasing of RLI, whereas the portion of root decreased. Specific leaf area (SLA) increased as RLI decreased. As regards the efects of shading on the forms of the seedlings, crown-shape-index [CSI; tan^<-1> (A/L), where A is the depth of crown and B is the length of the longest branch] decreased only when grown under heavy shading (7% RLI).
