摘要:为探寻持续干旱胁迫对典型常绿阔叶绿化植物滞尘能力与形态的影响，在开顶式气室内对不同供水条件下的金边黄杨（Euonymus japonicus Thunb.var.aurea-marginatus Hort）进行了35d的机动车尾气（模拟颗粒物污染源）暴露实验，分别分析了正常供水下与持续干旱下的金边黄杨对不同粒径颗粒物滞留量的变化，并观测了植株的形态变化。结果表明：（1）PD组（持续干旱+尾气暴露）的金边黄杨比P组（正常供水+尾气暴露）提前9d出现老叶的黄化、脱落现象，实验中仅PD组有成熟叶与幼叶的脱落（19d后）。（2）实验期间，PD组植株对各粒径颗粒物的平均滞留量比P组低2-3 μg/cm²，但在前28d，持续干旱对两组间滞尘量的影响不显著，而在第35天，则因PD组成熟叶的大面积脱落，干旱显著降低了各粒径颗粒物的滞留量约38.60%-46.54%，并使其滞尘能力大幅减弱。因此，短期的中轻度干旱对金边黄杨滞尘能力的影响较小，而极度干旱则加快了尾气暴露下植株成熟叶的脱落，并降低了其滞尘效应。



Abstract:The objective of this study was to explore the particle retention capability and the morphology changes of typical evergreen broad-leaved greening plants under continuous drought stress. The experiment was taken place in an open-top chamber by supplying vehicle exhaust (simulating particle pollution source) and different watering regimes on the plant, Euonymus japonicus Thunb. var. aurea-marginatus Hort, and monitoring particle accumulation and morphology changes. Two watering regimes were implemented: exhaust exposure with continuous drought (PD) and exhaust exposure with normal water supply (P). The results showed that (1) the yellowing and shedding of the old leaves of the E. japonicus var. aurea-marginatus in the group PD was 9 days earlier than that in the group P, and only the group PD presented the shedding of mature leaves and young leaves after 19 days. (2) The particle retention in each particle size fraction of group PD was 2-3 μg/cm² lower than that of group P after 35 days observation. There was no significant difference on particle retention between the two groups in the first 28 days. However, the continuous drought significantly reduced the particle retention in each particle size fraction by about 38.60%-46.54% on the 35th day. The significant change was attributed to many of the mature leaves of group PD fell off on the day of 35, which also indicated drought tolerance threshold. In conclusion, the short-term mild to moderate drought has slight effect on the particle retention ability of E. japonicus var. aurea-marginatus, while the extreme drought can accelerate the shedding of mature leaves under exhaust exposure, which may weaken its particle retention effect.





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