中文摘要：

为了比较中国东南沿海防护林主要树种的光合特性及水分利用策略，利用IJJ-6400便携式光合作用仪和PAM-2100叶绿素荧光仪对福建沿海防护林5个主要树种的光合特性以及荧光特性进行测定，并采用稳定同位素技术量化这些植物的水分来源利用比例以及水分利用效率。4种红树植物的光合同化速率、气孔导度、蒸腾速率显著高于木麻黄（Casuarinaequisetifolia）；外来红树植物无瓣海桑（Sonneratiaapetala）光合同化速率显著高于3个乡土红树植物。无瓣海桑叶片的最大相对电子传递速率（rETRmax）、半饱和光强（Ek）、Fv／Fm均显著大于乡土红树植物，表明无瓣海桑光合能力大于其他红树植物。植物茎木质部水稳定同位素的测定表明，外来种木麻黄和无瓣海桑主要利用地下水，而未利用海水和雨水；3种乡土红树植物主要利用地下水，但也利用海水和雨水的混合水。木麻黄的瞬时水分利用效率显著低于4种红树植物，但4种红树植物间的瞬时水分利用效率无显著差异。秋茄（Kandeliaobovata）和无瓣海桑的长期水分利用效率无显著差异，但二者显著高于桐花树（Aegicerascorniculatum）、白骨壤（Avicenniamarina）及木麻黄，说明前二者对水分的利用优于后三者，更适应于水分成为植物生长与存活限制因子的高盐环境。

英文摘要：

Abstract： By using LI-6400 portable photosynthesis system, PAM-2100 chlorophyll fluorescence analyzer, and stable isotope technique, this paper studied the leaf photosynthetic and fluores cence properties, water sources, and water use efficiency （ WUE ） of five main tree species in coastal shelterbelt forests in Fujian Province, aimed to understand the photosynthetic properties and water use strategies of main tree species in coastal shelterbelt forests in Southeast China. The net photosynthetic rate, intercellular carbon dioxide concentration, stomatal conductance, and transpiration rate of four mangrove species （Kandelia obovata, Aegiceras corniculatum, Avicennia marina, and Sonneratia apetala） were all significantly higher than Australian pine （Casuarina equisetifolia）, while the carbon assimilation capacity of the introduced species S. apetala was sig- nificantly higher than the native mangrove species. All the measured fluorescence parameters in- cluding maximum relative electron transport rate （rETRmax ） , half-saturation light intensity （Ek ）, and Fv/Fm of S. apetala were significantly greater than those of native mangroves, indicating that the photosynthetic capacity of S. apetala was also greater than that of the native mangrove spe-cies. Two exotic species （ C. equisetifolia and S. apetala） mainly relied on groundwater for their water sources, while all indigenous mangrove species could utilize groundwater, rainwater, and seawater. The instantaneous WUE of C. equisetifolia was significantly lower than that of the four mangrove species, while the latter four species had less difference in their instantaneous WUE. The long-term WUE of K. obovata and S. apetala had no significant difference, but was signifi cantly higher than that of A. corniculatum, A. marina, and C. equisetifolia, suggesting that K. obovata and S. apetala could better adapt to the high salt environment where water was the limit- ing factor for plant growth and survival.