PHOTO-ECOLOGICAL CHARACTERISTICS OF SIX BROAD-LEAVED SPECIES INCLUDING HEPTACODIUM MICONIOIDES IN THE TIANTAI MOUNTAINS IN ZHEJIANG PROVINCE
浙江天台山七子花等6种阔叶树光合生态特性

The photo-ecological characteristics of the six major broad-leaved species, including Heptacodium miconioides, in the Tiantai Mountains of Zhejiang Province were researched. In summer the diurnal variations of net photosynthetic rates (P n) of the six species are all "twin-peaked", with obvious "midday-depression" of photosynthesis. Their monthly variations of diurnal average P n are "single-peaked", with maximum values in August. From May to November, the average diurnal P n and monthly P n in Lithocarpus harlandii are highest, those in Acer amplum var. tientaiense are lowest, and those in H. miconioides are below average. Compared with evergreen species, the light compensation points (LCP) of H. miconioides are high, its light saturation points (LSP) are low, and its ecological ranges of light adaptability are narrow. The chlorophyll contents in L. harlandii are highest, and those in Castanopsis eyrei are lowest. There are no inevitable connections between chlorophyll contents and P n among different species. The monthly variations of chlorophyll contents in leaves of the same species are positively related to P n and LSP, but negatively related to LCP. In those species with high nitrate reductase activity, the P ns are high too. There is a correlation between the monthly variations of nitrate reductive activity and P n.