外来植物南美蟛蜞菊的繁殖特性

Reproductive Characteristics of Alien Plant Wedelia trilobata

南美蟛蜞菊Wedelia trilobata为菊科蟛蜞菊属植物,原产中、南美洲,由最初的绿化引进开始,现广泛分布于我国华南地区及沿海部分地区。其花为头状花序,有筒状花和假舌状花两种小花,其中筒状花的花瓣中附器结构(肉质刺状物)可能在一定程度影响了正常授粉;传粉媒介不存在障碍,主要媒介为角马蜂Polistesantennaks、酢浆灰蝶Pseudojijeeria maha。花粉活力和柱头可授性差,结实率很低,种子在正常条件下萌发率低。南美蟛蜞菊主要以无性繁殖为主,依靠匍匐茎不断占领新的空间,节节生根并在节上产生新的植株。南美蟛蜞菊的无性繁殖能力极强,其茎段的可塑性很大,扦插、压条试验显示,只要一个带有节的茎段就有成功发展扩大种群潜力,由此可见其潜在的入侵能力不可忽视。

Wedelia trilobata is a species of Asteraceae and primarily native to tropical Central and South America; it had been frequently introduced for gardening. Nowadays it has widely been distributed in the region of South China and other seaside. The flowers of W. trilobata are capitulum＇s and the florets include two types, which are tubular corolla and false tongue fower. The fleshy spinouts objected structure in the tubular corolla affect the natural polhnation. The pollination medium was normal and the main pollinators were Polistes antennaks and Pseudojijeeria maha. The pollen viability and stigma receptivity are weak. The seeding rate and seed germination rate are low. W. trilobata mainly relied on vegetative propagation to increase the community and its climbing stems to reach new space, which rooted and germinated new plants from the node. From the experiment by propagation of cutting and layering, it shows that W. trilobata has strong vegetative propagation and its stems show a high plasticity, and only a single stem with several nodes has the potential ability to increase the community. The above information showed that the potential invasive ability of W. trilobata can＇t be neglected.