飞机草的繁殖能力与种子的萌发特性

Reproductive capacity and seed germination characteristics of Chromolaena odorata

飞机草(Chromolaena odorata)是一种入侵性极强的外来杂草,现正在我国南部地区迅速传播,其繁殖特性与种子萌发对环境条件的适应能力是成功入侵扩散的前提。采用野外调查与室内试验相结合的方法,研究了飞机草的繁殖能力与种子的萌发特性。结果表明,飞机草能够进行无性繁殖,但其有性生殖能力更强,成熟植株的种子生产量高,种子质量轻,并且具有冠毛等附属结构。环境因子能够影响飞机草种子的萌发,其萌发的最适温度约为28℃,萌发过程中不需要特别的养分供应,并且能够忍耐一定程度的干旱胁迫。酸性环境能够促进飞机草种子的萌发,但当pH降至2.0时,其发芽率显著降低。掩埋处理能够抑制飞机草种子的萌发,当埋藏深度达3.0 cm时,所有的种子均不能正常萌发与出苗。

Chromolaena odorata is an alien weed with strong invasiveness and spreading rapidly in southern China at present.The successful invasion of this weed might be related to its reproductive traits and strong adaptability of seed germination to environmental conditions.We studied the reproductive capacity and seed germination characteristics of C.odorata by employing both field investigations and laboratory experiments.The results showed that C.odorata could reproduce clonally.However,its sexual reproductive capacity was much stronger.A single mature plant could produce approximate 480 thousands of seeds.Its seed was small and there are more than 27 pappus on a single seed.Seed germination of C.odorata was affected by environment factors.The optimum temperature for germination was 28 ℃.It did not require any additional nutrition for germination and could endure drought stress to some extent during germination process.Acidic conditions could accelerate its seed germination,but the percentage of germination was significantly decreased when pH was below 2.Germination could be inhibited by the buried treatment and no seedling emerged when seeds were planted 3.0 cm deep.