外来入侵植物薇甘菊(Mikania micrantha)对温度升高的响应

为探讨全球变化温度升高对外来入侵植物薇甘菊(Mikania micrantha)化感作用和入侵能力的影响,研究不同温度(22、26和30℃)处理对其种子萌发、幼苗生长、生物量分配、挥发物成分和化感作用的影响。结果表明,薇甘菊种子在温度为22、26和30℃时的萌发率分别为29.2%、52.4%和75.2%。30℃条件下薇甘菊种子萌发率最高,萌发速度快。温度升高显著增加薇甘菊茎的生长、增加对茎的生物量分配。GC-MS和GC测定显示,温度升高改变了薇甘菊挥发物的化学成分。同时,生物测定表明,温度升高增强薇甘菊挥发物对萝卜(Raphanus sativus)和油菜(Brassica campestris)的化感作用。说明温度升高促进了薇甘菊种子的萌发和生长,同时增强了该植物的化感作用,温度升高可能加速薇甘菊的生物入侵。

Responses of invasive weed Mikania micrantha to elevated air temperature

In order to evaluate the effects of elevated air temperature under global change on the allelopathy and invasiveness of Mikania micrantha,an important alien invasive plant species in China,this paper studied the seed germination,seedling growth,biomass allocation,volatile components,and allelopathic potential of the plant under effects of three temperature(22,26,and 30 ℃).After 3 days incubation,the seed germination rate of M.micrantha at 22,26,and 30 ℃ was 29.2%,52.4%,and 75.2%,respectively,being the highest at 30 ℃.Elevated temperature also increased the shoot length and biomass allocation to stem significantly.GC-MS and GC analyses showed that elevated temperature altered the chemical composition of the volatiles released from M.micrantha leaves.Bioassay demonstrated that elevated temperature increased the allelopathic effect of M.micrantha volatiles on the growth of Raphanus sativus and Brassica campestris seedlings.The results suggested that elevated temperature promoted the seed germination and seedling growth of M.micrantha,increased its allelopathic potential,and thereby,could accelerate the invasion of the plant.