[目的]了解热带季节雨林幼树个体光合光响应的生物学特性,为全球气候变化下热带雨林保护提供科学依据.[方法]在西双版纳热带季节雨林中选择林下云南玉蕊幼树,分别于雾凉季、干热季、雨季,测定其光合光响应特征的季节变化动态.[结果]云南玉蕊幼树林下Pnmax为雨季最大,干热季和雾凉季次之,分别为4.08、2.89和1.81 μmol/(m2·s),季节间具显著差异；Gs和Tr以雨季相对最高,WUE以干热季为最高,Ci以雾凉季为最高,它们在人工光源下的最大值分别为0.18 mmol/(m2·s)、1.59 mmol/( m2·s)、7.35μmol/mmol和4.55μmol/(m2·s)；Ci随光强及季节的变化与WUE呈相反趋势,而Gs与Tr变化趋势基本一致.[结论]热带季节雨林云南玉蕊幼树林下光合光响应特征具明显季节性,雨季中有比其他季节更为旺盛的光合特征,且幼树具有耐荫的特性.%[Objective ] The aim was to study on biological characteristics of photosynthetic response for sapling of Baningtonia macrostackya in seasonal rain forest, providing scientific references for protection of tropical rain forest under change of global climate. [Method] Saplings of Barringtonia macrostachya in Xishuangbanna tropical forest are chosen to research in foggy season, dry and hut season, and rainy season to measure dynamics of season changes. [Result ] For saplings of Barringtonia macrostachya in Yunnan Province, Pnmax was the biggest in rainy season, followed by dry and hot season and foggy season at 4.08 , 2. 89 and 1.81 μmol/ ( m2 ?s) respectively; Gs and Tr in rainv season were the highest and WUE in dry season was the highest; Gi achieved peak in foggy season, of which the highest values were 0. 18 and 1. 59 mmol/(m2 ? s), and 7.35 μmol/mmol and 455 mmol/(m2 ?s); Ci showed an opposite trend with that of WUE, and Gs and Tr changed similarly. [Conclusion ] Saplings of Barringtonia macrostachya in seasonal rain forest are of significant seasonal change in photosynthetic response, and saplings are shade tolerant.
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