寄生植物菟丝子防治外来种薇甘菊研究初探

A Study on the Control of Exotic Weed Mikania micrantha by Using Parasitic Cuscuta campestris

摘要:

利用寄生植物田野菟丝子(CuscutacampestrisYunker)作为外来杂草薇甘菊(MikaniamicranthaH.B.K.)的生物防治手段,研究了田野菟丝子对薇甘菊的光合作用及生长的影响。结果表明:田野菟丝子寄生于薇甘菊30 d左右,薇甘菊单株叶片数、地上茎长度和生物量开始减少,光合速率、蒸腾速率、气孔导度、叶绿素含量以及叶绿素荧光Fv/Fm也开始降低。经过约2个月时间,以上的几个生长指标和生理指标均显著降低。在野外自然状态下,田野菟丝子由最初撒播面积约0.01 m²,很快发展到20 m²左右的大块面积,离侵染源中心的最大扩散距离达到5 m以上。田野菟丝子寄生可以严重影响薇甘菊茎叶生长及开花结实,可望成为根本上解决薇甘菊危害的一种生物控制技术,而且也可以缓解药用菟丝子资源匮乏的问题。结合国内外最新进展,提出有关田野菟丝子与其寄主相互关系中亟待解决的几个问题。

Abstract:

Parasite Cuscuta campestris Yunker was examined for controlling the growth and spread of harmful weed Mikania micrantha H. B. K. The experiments were carried out to estimate biomass production by sowing the seeds of M. micrantha in sample plots in Shenzhen Xianhu Botanic Garden where this weed grew densely, and for physiological study by cultivation of both plants in pots. The result exhibited that the leaf number, stem length, and biomass dry weight of individual of the host M. micrantha began to decrease after the host was parasitized for about 30 days. Such decrease was obvious after 2 months of parasitism, so did the photosynthetic rate (P_n), transpiration rate (E), stomatal conductance (g_s), water use efficiency (WUE), chlorophyll content, and Fv/Fm. The parasite could spread rapidly extending to an area of 20 m² with longest distance of 5 m within 2 months. The parasite hampered the growth and reproduction of the host and depressed it even to die. It is suggested that C. campestris might be a promising plant for controlling this weed.