外来植物坚尼草生态学研究

坚尼草（Panicm maximum Jacq.^-）是一种外来草本植物，已逸为野生，扩展迅速，对本地草本植物构成一定的影响。其扩展能力与其生长和繁殖特点有很大关系。研究表明，坚尼草对环境的适应能力较强；植株较高大，生长迅速，有较强的竞争能力；花期长，单丛坚尼草从始穗到终穗，花期可长达6－7个月；同一穗的果实熟期不同，而且边熟边脱落，从抽穗的5－7d起开始有果实脱落，脱落时间可持续1个月左右，以抽穗2－3周为脱落高峰；不同时间成熟的果实，明发率也不同，7月份成熟的果实比9成熟的果实萌发率高。同一穗中，以抽穗后2－3周（果实脱落的高峰期）成熟的果实萌发率较高。果实成熟后，不能立即萌发，储存1－6个月，种子萌发率较高。

Ecological Studies on a Foreign Plant Panicum maximum Jacq.

Panicum maximum Jacq.，a foreign forage grass from africa,become a common plant in the field in Guangdong,Guangxi and Fujian.P.maximum is a tall grass with leaf height 1.2～1.8 m and inflorescence height 2～2.5 m in common habit in Guangzhou.It provided a production of 1.14 kg*m-2*a-1,a much higher production than that (about 0.5 kg*m-2*a-1) of the native common grass.It can continuously produce fruits for about 6～7 months by a flowering period of 6～7 months (from April to October),and by a fruit shedding period of about 1 month for individual spike.Fruit shedding took place about 7 days after the inflorescence came out,and reached the peak in the 2～3 weeks after the heading of the spike.Fruits collected in July had higher germination than that in September.It is also true for the fruits collected in peak shedding time than the fruits collected later on.Fresh fruits could not germinate.Fruits showed very few germination after 1 week's storage and gave the best germination after a storage of 6～8 months.All the characteristics in growth and reproduction were favorable for its rapid expansion in the field.