重金属污染对入侵植物与本地植物生态学互作关系的影响

外来植物入侵和重金属污染均是我国极为突出的环境问题，由于入侵植物普遍具有较强的重金属耐受性，明确重金属污染对外来植物入侵的影响将有助于深入解析外来植物的入侵机制。在重金属的影响下，入侵植物能够利用多种生物与非生物因子与污染生境中的本地植物形成复杂的生态学互作关系。本地植物可以作为先锋物种促进入侵植物的建群，而入侵植物则可以影响本地的土壤环境和昆虫群落，通过元素化感和元素防御作用抑制本地植物的生长、繁殖与种群维持。为了验证这些假设，本项目以污染生境中常见的入侵植物空心莲子草和本地植物莲子草为研究对象，结合控制实验、生物测定、样方跟踪、野外调查等手段，从植物-植物互作、植物-昆虫互作、土壤-植物关系等多种角度综合检验重金属对入侵植物-本地植物生态学互作关系的影响，揭示入侵植物对本地植物的影响作用途径，为预测外来植物的入侵性及生境的可入侵性提供科学依据，丰富和完善入侵生态学理论。

Both alien plant invasion and heavy metal pollution are among the most prominent environmental problems in China. Since many invasive plants possess high tolerance to heavy metals, it will help reveal the mechanisms underlying alien plant invasion. Invasive plants would form complex ecological interactions with native plants under heavy metal stress through a variety of biotic and abiotic factors in contaminated habitats. Native plants can act as pioneer species that facilitate the establishment of invasive plants, in turn invasive plants may inhibit the growth, reproduction and population maintenance of native plants through the influenced soil property (e.g. elemental allelopathy) and insect communities (e.g. elemental defence) during the process of invasion. To test these hypotheses, the invasive plant, Alternanthera philoxeroides, and native plant, Alternanthera sessilis, both of which are common species in contaminated habitats, were used to examine the effects of heavy metals on the ecological interactions between invasive plant and native plant. To reveal the influence pathway of invasive plant on native plant, controlled experiment, bioassays, population dynamics surveys and field surveys will be conducted to analyze the effects of heavy metal on interspecific interaction, plant-insect interaction and soil-plant relationship. Our study will provide a scientific basis for the predictive theory on plant invasiveness and community invisibility, and the invasion ecology theory will be further improved.