紫茎泽兰与伴生植物小藜的竞争效应及其生理生化特征

外来入侵物种紫茎泽兰（Ageratina adenophora Sprengel）是一种世界性入侵杂草，其与本地物种的竞争会对生态系统结构和演替造成严重影响，带来较大经济损失；拟通过分析紫茎泽兰与本地物种小藜的竞争效应及生理生化特征，以探讨外来入侵物种紫茎泽兰的竞争机理。在温室条件下，设置紫茎泽兰、小藜（Chenopodium serotinum）的种内和种间竞争盆栽试验，测定了两种植物不同处理下的植株生物量；并通过氮蓝四唑光化还原法、紫外吸收法、三氯乙酸法和酸性茚三酮法，分别测定了功能叶片的超氧化物歧化酶活性、过氧化氢酶活性、丙二醛含量、脯氨酸含量。结果表明：紫茎泽兰与小藜混种时，紫茎泽兰的单株生物量、相对产量（RY）均显著高于小藜对应指标，其竞争平衡指数（CB）显著大于0，而相对产量总和（RYT）显著小于1。混种与单种的结果比较表明，紫茎泽兰的混种生物量比在单种时显著增高，增幅达22.01%；而小藜的混种生物量比在单种时显著降低，降低了44.81%。在混种中，紫茎泽兰功能叶片的丙二醛、脯氨酸含量均比在单种时显著降低，而超氧化物歧化酶、过氧化氢酶活性均比在单种时显著升高；小藜功能叶片的丙二醛含量显著高于单种，而脯氨酸含量、超氧化物歧化酶活性、过氧化氢酶活性与单种无显著变化。这说明紫茎泽兰的相对竞争能力比小藜强，紫茎泽兰通过调整生理生化特征来应对种间竞争可能是其竞争取胜的重要策略。

Competitive effects and physiological and biochemical properties of Ageratina adenophora and its associated species Chenopodium serotinum

Alien invasive species Ageratina adenophora is a worldwide invasion weeds. The competitions between Ageratina adenophora aand native species can casuse serious influence on ecosystem structure and succession, and result in larger economic losses. Studied in this paper through the analysis of Ageratina adenophora compete with native species of Chenopodium serotinum effect and physiological and biochemical characteristics, in order to investigate the competition mechanism of invasive species Ageratina adenophora. A pairwise competitive design was used to evaluate the intra- and inter-specific competition interaction between Ageratina adenophora and Chenopodium serotinum in a greenhouse experiment. By nitroblue tetrazolium photochemical reduction method, ultraviolet absorption method, method of trichloroacetic acid and indene three method, respectively, to determine the functional leaves of superoxide dismutase, catalase activity and content, praline content. Competitive effect and response were measured as the relative yield （RY） and relative yield total （RYT） and competitive balance index （CB）, and physiological and biochemical properties for each target-neighbor species combination. The results show that the total biomass and RY and CB of A. adenophora were significant higher than those of C. serotinum, the CB of A. adenophora were significant higher than 0, the RYT was significant lower than 1. The total biomass of A. adenophora in mixture increased significantly by 22.01%compared to those in monoculture. However, the total biomass of C. serotinum in mixture decreased significantly by 44.81% compared to those in monoculture. Anymore, the malondialdehyde content （MDA） and proline content （Pro） in the leaves of A. adenophora in mixture decreased significantly compared to those in monoculture, respectively. However, the MDA and Pro in the leaves of C. serotinum in mixture increased significantly or showed no significant difference compared to those in monoculture. The superoxide dismutase （SOD） activities, catalase （CAT） activity in the leaves of A. adenophora in mixture were significant higher than those in monoculture. However, the SOD activities, CAT activity in the leaves of C. serotinum between in monoculture and in mixture were no significant difference. Together, the relative competitive ability of A. adenophora was higher than that of C. serotinum. In competition, A. adenophora showed stronger adjusting mechanism in the change of physiological and biochemical properties in the leaves compared to C. serotinum, which may be a potential important strategy for A. adenophora. out-competed C. serotinum in mixture.