Combination effects of heavy metal and inter-specific competition on the invasiveness of Alternanthera philoxeroides
Combination effects of heavy metal and inter-specific competition on the invasiveness of Alternanthera philoxeroides
复制标题
重金属和种间竞争对空心莲子草入侵力的联合影响
DOI：
10.1016/j.envexpbot.2021.104532
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发表时间：
2021-09
影响因子：
5.7
通讯作者：
Yan Wang;Chao Chen;Yuntao Xiong;Yi Wang;Qingjun Li
中科院分区：
文献类型：
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作者：
Yan Wang;Chao Chen;Yuntao Xiong;Yi Wang;Qingjun Li
Inter-specific competition is an essential factor affecting the invasiveness of alien plants. Although many exotic invasive plants are characterised by a high tolerance to many pollutants, e.g. heavy metals, little is currently known regarding the impact of heavy metals on the interaction between native and invasive plants. In this study, we used the invasive plantAlternanthera philoxeroides(Mart.) Griseb. and its native congenerAlternanthera sessilis(L.) R.Br. ex DC to assess their competitive interaction in response to treatments with copper, cadmium, and zinc applied at different concentrations (10, 30, 60, and 100 mg kg−1for Cd; 200, 400, and 1000 mg kg−1for Cu; and 500, 1000, and 2000 mg kg−1for Zn), along with a control treatment. We accordingly found that both invasive and native plants show high tolerance to heavy metals; however, the tolerance index ofA. philoxeroidesincreased significantly from monoculture to mixed culture in response to Cu and Cd treatments. In addition,A. philoxeroidesshowed greater phenotypic plasticity to culture type than its native congener. Furthermore, the specific leaf area ofA. philoxeroidesin the mixed culture was found to be higher than that in monoculture. Additionally, in response to Cu and Cd treatments, the biomass ofA. philoxeroidesin mixed culture was notably shifted from the roots to shoots, in contrast to the control group, the variances inA. philoxeroidesresponses in monoculture were less perceptible. We speculate that such high phenotypic plasticity may represent an important tolerance strategy for invasive plants that can enhance their competitive ability against native plants under conditions of heavy metal stress, and consequently a combination of heavy metal stress and inter-specific competition would be conducive to the invasiveness ofA. philoxeroides, particularly in habitats characterised by high levels of heavy metal pollution.
