[Effects of shade on photosynthetic characteristics and chlorophyll fluorescence of Ardisia violacea].

Abstract

Ardisia violacea is one of the rare and endangered species, and distributes only in Zhejiang and Taiwan Provinces in China. In order to understand the light requirement and adaptability of A. violacea, the effects of different light intensities (shading rate of 90%, 60%, 25%, and the full light) on leaf photosynthetic characteristics and chlorophyll fluorescence of A. violacea were studied. The photosynthetic rate (Pn) and stomatal conductance (g(s)) of A. violacea varied as a bimodal curve with a 'midday depression' phenomenon in full bright light, and as a unimodal curve in the shading treatments. With the increasing shading rate, the Pn and apparent quantum efficiency (AQY) first increased, and then decreased, the light compensation point (LCP) and light saturation point (LSP) decreased, and the g(s), transpiration rate (Tr), original light energy conversion (Fv/Fm) and potential activity of PS II (Fv/Fo) increased. The total quantity of chlorophyll and the carotenoid (Car) content increased, and Chl a/b decreased under shading conditions. When the shading rate was 25%, the specific leaf mass (LMA) and root to shoot (R/T) ratio of A. violacea reached the maximum. A. violacea possessed a strong flexibility to different light environments, suggesting that light could not be the main limiting factor for natural regeneration of A. violacea populations.