不同林木种群对紫茎泽兰营养生长和生殖生长的影响

外来植物紫茎泽兰（Eupatorlum adenophorum）入侵我国西南地区并造成了严重的生态灾难，通过研究不同林木种群下紫茎泽兰的生长特性和发生规律，有助于从生态学角度为紫茎泽兰的综合防控提供事实依据。我们分别于2009、2011和2012年在西昌袁家山上开展了不同人工林木群落下紫茎泽兰营养生长和生殖生长特性的调查。调查研究的结果表明，阔叶林（青冈林）、阔叶针叶混交林（油茶柏树混交林）和阔叶混交林（油茶青冈混交林）下光照强度显著低于两种针叶林（落叶松林和柏树林）和空旷地，光照强度较空旷地减少率均在90％以上。空旷地紫茎泽兰的发生密度可达到111-218株·m-2，两种针叶林（落叶松林和柏树林）对紫茎泽兰的发生表现出一定的抑制作用，抑制率能达到46．2％～77．1％。油茶柏树混交林和青冈林下紫茎泽兰只有零星发生，对紫茎泽兰发生抑制率3年均在90％以上，而在油茶青冈混交林下未发现有紫茎泽兰发生。空旷地紫茎泽兰株高和分枝数均要显著高于其他人工林木群落，单株株高可达160．5～180．3cm，单株分枝数达到14．9～17．4，其中两种针叶林下紫茎泽兰的株高和分枝数要显著高于两种混交林和青冈林，株高达到59．5～113．4cm，单株分枝数为6．4～14．8。此外种植人工林木也显著抑制了紫茎泽兰的开花结实，空旷地紫茎泽兰单株种子量能达到8314～15410粒，两种针叶林（落叶松林和柏树林）下紫茎泽兰单株种子发生量为1330-4666-3粒，而两种混交林和青冈林下紫茎泽兰只有零星开花或不开花结实。相关性分析结果显示，光照强度的大小与紫茎泽兰的发生密度、株高、分枝数、单株花苞数、单株种子数都呈显著正相关，即光照强度显著影响着紫茎泽兰的发生密度、生长以及开花结实。阔叶林下光照强度的减弱是导致紫茎泽兰发生量减少原因之一。开展植树造林，采用种植青冈林、油茶青冈、油茶柏树混交林等阔叶混栽的方式对紫茎泽兰的发生不仅能起到显著的生态控制效果，而且能绿化荒山，给农民带来经济效益。

Vegetative and reproductive growth of Eupatorium adenophorum Spreng in different forest communities

Eupatorium adenophorum Spreng is one of the worst invasive alien plants into China. It brings great harm to the ecological environment in the Southwest of China. Occurrence and growth ofE. adenophorum in different forest communities were evaluated in order to provide integrate strategies on ecology control of E. adenophorum. The growth characteristics of E. adenophorum in vegetative and reproductive periods under different manmade forest communities were investigated in the year 2009, 2011 and 2012. The results indicated that light intensity of E. adenophorum in broadleaved forest, broadleaved-needle mixed forest and broadleaved mixed forest were significantly lower than needle-leaved forest and bare land, and light intensity was decreased by 90% compared to bare land. Density ofE. adenophorum in bare land was 111-218 plants＇m2 and the quantity E. adenophorum in needle-leaved forest was inhibited compared to bare land and the inhibition rate ranged from 46.2%-77.1%. The inhibitory effect was also observed in broadleaved forest, broadleaved-needle mixed forest and broadleaved mixed forest and the inhibition rate reached above 90% during the last three years. Plant height and branches in needle-leaved forest were significantly higher than two kinds of mixed forests and broadleaved forest, but lower than bare land. Moreover, the quantity of buds and seeds orE. adenophorum under different manmade forests was also inhibited compared to bare land. Seed quantity in bare land ranged from 8 314-15 410 per plant, which was 1 330~4 666.3 in needle-leaved forest. Few buds were observed in broadleaved, broadleavedoneedle mixed and broadleaved mixed forest. A positive correlation was observed between light intensity and density, plant height, branches, buds and seeds of E. adenophorum. Light could be an important factor affecting the growth and distribution of E. adenophorum. Ecological control of E. adenophorum by mixed plantation of broadleaved forest not only provides good efficacy, but also brings direct economic benefits to farmers.