Response of Photosynthesis to Growth Light Intensity in Some South Subtropical Woody Plants
几种南亚热带木本植物光合作用对生长光强的响应

One-year-old seedlings of four woody dominant species of different succession stages from southsubtropical forest were potted under 100% and 32% of natural light for six months. Light response curve ofphotosynthesis and some parameters of chlorophyll fluorescence in these species were determined. Under 100% of natural light, Pinus massoniana had highest values of maximum photosynthetic rate (Pmax), light saturation point(LSP), light compensation point(LCP), dark respiration rate(Rd), the apparent quantum yield(AQY), leaf total electron flow rate(JF) and photochemical fluorescence quenching (qP), whereas Cryptocarya concinnaexhibited maximum fractions of total electron flow partitioned to photorespiration (JO/JF). AQY under 100% of natural light was in the order of Pinus massoniana > Castanopsis fissa > Schima superba > Cryptocarya concinna, while the result was the reverse under 32% of natural light. These suggest that Pinus massoniana, the pioneer species at early succession stage of forest community,is the plant species adapted to high light intensity, while Cryptocarya concinna, a species at succession climax stage has an advantage in light utility under low lightenvironment. The results also support that the increasing ratio of total electron flow allocation to photorespiration in Cryptocarya concinna is one of the strategies to protect itself against high light damage.