Effects of waterlogging stress on leaf gas exchange of Michelia chapensis, Schima wallichii, Rh-odoleia championii and Cinnamomum camphora were investigated so as to understand the physiological mechanism of waterlogging resistance of these four kind seedlings and provide a reference for the selection of waterlogging resistant species in southern China .The results showed that net photosynthetic rate ( Pn) of the four kind seedlings tended to decrease with increasing waterlogging time .Pn of M.chapensis, S. wallichii, R.championii and C.camphora reached their minimum with values of 1.87, 0.43, -0.26 and 0.62 μmol· m-2 · s-1 , respectively, in 35 days under waterlogging stress , and their stomatal con-ductance (Gs) tended to decrease with values of 0.032, 0.005, 0.008 and 0.006 mol· m-2· s-1, re-spectively, in 35 days under waterlogging stress;intercellular mole fraction of CO2(xCO2) of M.chapen-sis,S.wallichii and C.camphora decreased followed by an increase , whereas xCO2 of R.championii con-tinuously increased;with increasing waterlogging time , transpiration rate ( Tr) of M.chapensis, S.walli-chii, R.championii and C.camphora tended to decrease with values of 0.04, 0.13, 0.02, 0.10 mmol· m-2 · s-1 , respectively , in 35 days under waterlogging stress .The waterlogging resistance of the four kind seedlings was evaluated using principal component analysis , and the order of waterlogging re-sistance was M.chapensis >S.wallichii >C.camphora >R.championii.%对乐昌含笑Michelia chapensis、红荷Schima wallichii、红苞木Rhodoleia championii和樟树Cinnamomum camphora幼苗在根部淹水胁迫下的叶片气体交换参数进行了研究，以便从光合生理角度了解这4种树种的耐水淹生理机制．结果表明，随着水淹胁迫时间的增加，4种幼苗的净光合速率均呈下降趋势，35 d 时均达到最小值，分别为1.87、0.43、-0.26和0.62μmol· m-2· s-1；4种幼苗的叶片气孔导度和蒸腾速率均呈下降趋势，35 d 时4种幼苗的气孔导度分别为0.032、0.005、0.008和0.006 mol · m-2· s-1，蒸腾速率分别为0.04、0.13、0.02和0.10 mmol· m-2· s-1；乐昌含笑、红荷和樟树的细胞间隙CO2摩尔分数先降后升，而红苞木的细胞间隙CO2摩尔分数持续上升；由主成分分析法得出4种幼苗耐水淹能力为乐昌含笑＞红荷＞樟树＞红苞木．
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