Seasonal variations of photosynthetic characteristics of 3 evergreen braoad-leaved species in Tiantai Mountains

Studies were carried out on seasonal variations of photosynthetic characteristics of three evergreen broad-leaved species in Tiantai Mountains, Zhejiang province, including Lithocarpus harlandii, Rhododendron fortunei, Castanopsis eyeri. The results showed that: 1) In summer the diurnal variations of net photosynthetic rates (Pn) of the three species were all “twin-peaked”, with obvious “midday-depression” of photosynthesis. 2) The values of average daily Pn were summerautumnspringwinter by season, and L. harlandiiC. eyeriRh. fortunei by species. 3) Average daily Pn of the three evergreen broad-leaved species were higher than layer species such as Sargentodoxa cuneata and deciduous species such as Heptacodium miconioides. 4) The light compensation points (LCP) of the three species were lowest in summer, and their light saturation points (LSP) were highest. 5) The chlorophyll contents of the three species topped in summer, and a/b of chlorophyll were the lowest. There was certain relation between chlorophyll contents and Pn in the same species. The seasonal variations of chlorophyll contents in leaves of the same species were positively related to LSP, but negatively to LCP.