Identity recognition (competition or altruism depending on genetic relationship) in plants was reported more infrequently than in animals. Few studies found identity recognition can help reducing competition between kin plants, and increasing population fitness. The exotic invasive plants usually form dense monoculture distribution, but native plants rarely distribute similarly. It might due to the invader had higher identity recognition ability, which could reduce intraspecific competition and enhance overall population fitness. In this study, we compared identity recognition ability between invasive Eupatorium adenophorum and two native congeners (Eupatorium fortunei and Eupatorium lindleyanum) in different nutrient condition and planting density. The results indicated that all three species did not show identity recognition ability in low and intermediate density condition. However, in high density condition, invasive E. adenophorum shew higher identity recognition ability than two native congeners. Recognition could alleviate intraspecific competition of invasive E. adenophorum through reducing carbon accumulation and RMF, but increasing the height to enhance light use efficiency. This strategy might contribute to high population fitness of E. adenophorum when it grew in high densities. This is the first study to explore the relationship between identity recognition and exotic plant invasion.

在植物中的身份识别（竞争或利他主义取决于遗传关系）的报道比在动物中的报道少。很少有研究发现身份识别可以帮助减少亲缘植物之间的竞争，并提高种群适应度。外来入侵植物通常形成密集的单一栽培分布，但本地植物很少以类似的方式分布。这可能是由于入侵者具有更高的身份识别能力，从而可以减少种内竞争并增强总体人口适应性。在这项研究中，我们比较了入侵紫茎泽兰和两个天然同源物（紫茎泽兰和and兰）的身份识别能力。）在不同的养分条件和种植密度下。结果表明，这三个物种在中低密度条件下均未表现出身份识别能力。然而，在高密度条件下，入侵性紫茎泽兰具有比两个天然同源物更高的身份识别能力。识别可通过减少碳积累和RMF减轻入侵性紫茎泽兰的种内竞争，但增加高度以提高光利用效率。当高密度生长时，该策略可能有助于紫茎泽兰的高种群适应性。这是探索身份识别与外来植物入侵之间关系的第一项研究。