中文摘要：

紫茎泽兰（Eupatorium adenophorum）是一种入侵能力极强的世界性恶性杂草。通过不同种植密度的紫茎泽兰盆栽试验，探讨种内竞争对紫茎泽兰个体生长的影响。结果表明，种内竞争降低了紫茎泽兰个体株高、叶片数、根蘖株数和生物量的增长。种植密度与生物量2者的对数值呈负相关关系（r^2=0．99，斜率=-5／6）。同时，随着种植密度增加，种内竞争加剧，抑制作用增强，种群内部大小等级差异也增大，表明不同个体受到了不同的拥挤压力。但是，高密度的紫茎泽兰种群在强烈竞争下，个体会控制根蘖株的形成、死亡，从而减少资源的消耗，保证种群对生境的长期占领。建议在进行紫茎泽兰的替代控制时，应注意替代物种的先植，选择优于紫茎泽兰萌发的植物作为替代物种，通过邻体干扰效应抑制紫茎泽兰的生长。

英文摘要：

Eupatorium adenophorum is a worldwide noxious weed with a very high invasive ability. An interspecific competition experiment was conducted in a greenhouse to observe growth of E. adenophorum affected by interspecific competition, and to interpret the relationship between the interspecific competition and population density. Result indicate that interspecific competition reduced average plant height and lamina number, root sprout number, and biomass of individual E. adenophorum as planting density increased from 25 to 700 plants ·m^-2. The lg biomass was highly negatively correlated with the lg density with r^2 = 0.99 and gradient = - 5/6. Meanwhile, differences between plants of various size hierarchy intensified as the plant density increased, indicating that different plant individuals were exposed to different density stress within the community. When the planting density was very high, E. adenophorum plants would control formation of root sprouts, or even let them die so as to reduce their consumption of resources for survival in the habitat. This suggested that vicarious species should be planted and germinated earlier than E. adenophorum once applying substitution method, by which E. adenophrum could be suppressed by the planted vicarious neighbors.