报告了内蒙古浑善达克沙地不同生境下97种不同科、属植物的光合速率、蒸腾速率和水分利用效率特征。结果表明：猪毛菜（Salsola collina）、沙米（Agriophyllum pungens）、黑沙蒿（Artemisia ordosica）、狗尾草（Setaria viridis）、柠条（Caragana microphylla）等具有C4光合碳同化途径或具固氮能力的植物种具有较高的光合能力，其净光合速率大于30 μmol CO2·m-2·s-1, 而大部分具C3途径和无固氮能力的植物种的净光合速率较低，为1.29～10 μmol CO2·m-2·s-1；71%的植物种蒸腾速率集中在2～10 mmol H2O·m-2·s-1。所选出的高光效植物种在当地植被恢复与重建过程中应有很高利用价值。C4植物种占所测植物种的1/5左右，主要分布于固定沙丘上，且随着生境土壤湿度的增大其与C3植物种的光合速率差异逐渐缩小。在3种生境条件下，灌木和草本植物的光合速率和蒸腾速率顺序为：低湿地> 滩地 > 固定沙丘(p<0.01)，而乔木为固定沙丘>滩地 (p<0.01) 。不同功能型植物的气体交换特征随生境的不同而异, 在固定沙丘上, 草本的蒸腾速率最高，乔木的水分利用率最高，三者光合速率相差不大。
Net photosynthetic rates (Pn), transpiration rates (E) and water se efficiencies (WUE) of 97 species among different habitats of Hunshandak Sand Area in Inner Mongolia were investigated. The results showed that some species such as Salsola collina, Setaria viridis, Agriophyllum pungens, Artemisia ordosica, Caragana microphylla and some other species which possess the C4 photosynthe
tic pathway or with nitrogen fixation ability had higher net photosynthesis rates > 30 μmol
CO2·m-2·s-1), while most of the species which possess the C3 photosyntheti
c pathway or lacked nitrogen fixation ability had lower photosynthesis rates (1.
29-10 μmol CO2·m-2·s-1). Species with transpiration rates between 2-10 mmol
H2O·CO2·m-2·s-1 comprised 71% of the species studied. The selected species which
have high photosynthetic capability should be preferentially used in rehabilitating
degraded grassland. Of the plants measured, C4 species are mainly distributed on
fixed sand dunes. The differences between C4 and C3 species decreased graduall
y with increasing soil moisture. Of the habitats studied, the values of both Pn
and E of grasses and shrubs were found to be in the order of wetland > lowla
nd > fixed dunes, whereas those of trees were in the order of fixed dune > lowland.
The order of WU was opposite to those of Pn and E. Gas exchange traits
of three growth forms growing in different habitats were widely different.
In fixed dunes, Pn of three growth forms were not greatly different,
while the highest E and WUE were found in grasses and trees, respectively.