环境因素对紫茎泽兰种子萌发的影响

Influence of Environmental Factors on Seed Germination of Eupatorium adenophorum Spreng

紫茎泽兰是一种入侵性极强的外来杂草,其种子对环境条件的适应能力是其成功入侵的关键。本研究采用实验生态学的方法,在室内外系统研究了储藏条件、地面覆盖物、pH值及温度对紫茎泽兰种子萌发的影响。结果表明,紫茎泽兰种子萌发需要适合的环境条件。地面覆盖可以有效控制紫茎泽兰种子的萌发,5mm的覆盖物就可以显著降低种子发芽数量,在枯枝落叶厚度超过20mm时紫茎泽兰种子几乎不能萌发。室温条件下储藏一年,种子萌发率不低于60%,而在低温干藏(5℃)和低温沙藏(5℃)的条件下,可以有效延长种子寿命。紫茎泽兰种子对pH和温度均有一个很宽的适应范围,pH值在3.5￣9.5和温度梯度在低温10℃到高温50℃/20℃之间种子均可以萌发。本研究结果对于揭示紫茎泽兰的入侵机理以及探讨生态系统对于紫茎泽兰入侵的抵御机制具有重要的参考价值。

The Crofton weed （Eupatorium adenophorum Spreng.） is an alien species with strong invisibility. The successful invasion of this weed might be due to its strong ability of adaptation to the environment. This study was carried out in laboratory and field by using the method of experimental ecology, the effects of storage conditions, superstratum of the ground, pH and temperatures on the seed germination were observed systematically. It was found that the suitable environment conditions are required for seed germination of E. adenophorum. The seed germination could be deeply affected by superstratum of the ground, 5 mm superstratum could reduce the germination rate significantly and few seed could germinate when the ground was covered with 20mm of defoliation and deadwood. Seed germination rate could still amount to over 60% when seed is stored for one year under room temperature, but low temperature （5℃） and sand storage （5℃） can effectively lengthen longevity of the seed. The seed could adapt a wide range of pH and temperatures for germination, and the seed could germinate in the environment with pH ranging from 3.5 to 9.5 and temperatures ranging from 10℃ to 50℃. The results of this study had important reference values for explaining the invasion mechanism and discussing the defense mechanisms of ecosystems against the invasion of E. adenophorum.