三种相思植物对短期大气污染的响应

3种2－3年生相思盆栽于代表不同污染程度的交通繁忙区、工业生产区和相对清洁区，4个月后进行植物叶片气体交换和叶绿素荧光特征参数的测定。结果表明，生长在污染区的相思植物的净光合速率（Pn）、气孔导度（gs）和光系统Ⅱ原初光化学效率（Fv／Fm）均出现不同程度的下降，下降幅度因植物种类和污染类型的不同而有差异，不同实验点上大腺相思叶片蒸腾速率（E）和水分利用效率（WUE）则维持相对稳定，多花和流苏相思的WUE均以污染环境下较低，根据Pn、gs和Fv/Fm的变化以及实验点上其它植物对应测定值比，推测3种相思植物对大气污染都表现出中等强度的抗性，且多花相思和流苏相思相对好于大腺相思。

Responses of three acacia species seedlings exposed to short-term air pollution

Measurements on gas exchange parameters have been made in leaves of three 2 to-3 year-old Acacia species seedlings transplanted and grown under different polluted sites for 4 months by using LCA-4 photosynthesis system. Possible effects of air pollution imposed on plants and their tolerance were evaluated. The net photosynthetic rate(Pn), stomatal conductance(gs) and the photochemical efficiency of the PSII(Fv/Fm) differed among species and generally decreased under polluted area. The transpiration rate(E) and water use efficiency (WUE) in leaves of Acacia macradenia maintained relatively stable among all the three experimental sites, but P,/E of Acacia floribunda and Acacia fimbriata decreased under polluted sites, when compared with those under the relatively clean area. Based on the changes in Pn, gs, and Fv/Fm, and compared these Fv/Fm values with other plants, it can be concluded that the three Acacia species exhibited moderate tolerance, and Acacia floribunda and Acacia fimbriata showed slightly higher tolerance than Acacia macradenia.