两种亚热带树种在三种光强条件下光合作用和光抑制.pdfVIP

PHOTOSYNTHETICA 43 (4): 567-574, 2005 Photosynthesis and photoinhibition after night chilling in seedlings of two tropical tree species grown under three irradiances *, **,*** * Y.-L. FENG and K.-F. CAO Kunming Division, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, * 88 Xuefu Road, Kunming 650223, China ** College of Life Sciences, Hebei University, 2 Hezuo Road, Baoding 071002, China Abstract We investigated the physiological effect of night chilling (CN) on potted seedlings of two tropical tree species, Calo- phyllum polyanthum and Linociera insignis, in Xishuangbanna, southwest China. Seedlings grown under 8, 25, and 50 % daylight for five months were moved to a 4–6 °C cold storage house for three consecutive nights, and returned to the original shaded sites during the day. CN resulted in strong suppression of photosynthesis and stomatal conductance for L . insignis, and reduced photorespiration rates, carboxylation efficiency, and maximum photochemical efficiency of photosystem 2 (PS2) at dawn and midday for both species. CN increased dawn and midday rates of non-photochemical quenching, and the contents of malondialdehyde and H O for both species. CN also induced inactivation or destruction 2 2 of PS2 reaction centres. The impacts of CN on tropical seedlings increased with the number of CN. Shading could signi- ficantly mitigate the adverse effects of CN for both species. After 3-d-recovery, gas exchange and fluorescence para- meters for both species returned to pre-treatment levels in most cases. Thus CN induced mainly stom