交通尾气污染对城市绿化乡土树种的影响:气孔、光合生理的响应

Effects of Auto-exhaust Pollution on Four Native Ornamental Trees: Stomatal and Photosynthetic Responses

摘要:

以生长在交通繁忙的东莞大道沿线的4种常见乡土绿化树种山杜英(Elaeocarpus sylvestris)、海南蒲桃(Syzygium hainanense)、小叶榕(Ficus microcarpa var. pusillifolia)和樟树(Cinnamomum philippinense)为材料,研究了城市交通尾气污染对植物的影响以及乡土植物在城市绿化中的适应特征。结果表明,4种植物的气孔形态没有明显差异,但污染环境中的气孔密度均显著增加,其中山杜英增加幅度最大。各树种的叶绿素和类胡萝卜素含量均发生了不同的适应性变化,但变化规律不一致。除樟树外,其它3种植物的最大净光合速率均提高,但气孔导度和胞间二氧化碳浓度的变化不一致。植物对大气污染的响应程度和方式存在种间差异。因此,4种植物通过形态和生理可塑性的改变以适应交通尾气污染环境。

Abstract:

The stomatal and photosynthetic responses of four native ornamental species, such as Elaeocarpus sylvestris, Syzygium hainanense, Ficus microcarpa var. pusillifolia, and Cinnamomum philippinense grown in heavy traffic Dongguan Road were studied. The results showed that stomatal morphology had no difference among four species, while stomatal density of 4 species at Dongguan Road increased significantly, in which Elaeocarpus sylvestris increased most. The contents of chlorophyll and carotenoid of 4 species in Dongguan Road had different adaptive changes, but the variations were inconsistent. Except for C. philippinense, the maxium net photosynthesis rate (P_max) increased at Dongguan Road, but the changes of stomatal conductance and intercellular CO₂ concentration were inconsistent. The responses to auto-exhaust pollution were different among 4 species. Therefore, the 4 species adapted to traffic exhaust pollution by changing morphological characters and physiological properties.