广西岩溶石山飞机草种群的繁殖特征

Reproductive Characteristics of Eupatorium odoratum Populations in Karst Rocky Mountain in Guangxi

对广西岩溶石山3个典型群落(飞机草优势群落、黄荆条-飞机草混合群落和类芦-蔓生莠竹群落)中飞机草(Eupatorium odoratum)种群的繁殖特征进行了研究。结果表明:3个群落中飞机草的头状花序数为520～3281个m-2;种子产量为12941～74386粒m-2;头状花序的平均种子数为22～25粒;种子千粒重为0.17～0.19 g。混合群落中飞机草的单株头状花序数和种子产量与伴生群落的差异显著,而飞机草优势群落与这两个群落无显著差异。单株飞机草的种子产量与株高、生物量呈正相关;单位面积的种子产量与开花植株数、头状花序数呈正相关,而与盖度的相关性较小。飞机草在干旱贫瘠的岩溶石山的3个群落中均能够产生大量轻的种子,具有强大的繁殖能力,表现出较强的入侵性,并能根据环境的变化而选择相应的繁殖策略,最大限度的适应环境。

The reproductive characteristics of Eupatorium odoratum population in three typical communities,such as E.odoratum community（dominancy community）,Vitex negundo-E.odoratum community（mixed community）,and Neyraudia reynaudiana-Microstegium vegans community（concomitant community）,were studied in karst rocky mountain in Guangxi.The results showed that the number of capitulum of E.odoratum in 1 square meter ranged from 520 to 3281,and seed yield from 12941 to 74386 grains m-2,each capitulum produced 22 to 25 seeds and the 1000-seed-weight ranged from 0.17 to 0.19 g.The number of capitulum and seed yield per individual in mixed community were significantly different from those in concomitant community,but there were not significant difference between dominant community and two another communities.There was a positive correlation between individual seed yield and plant height,as well as biomass.Seed yield in unit area was positively correlated with the number of flowering plants and capitulum,but was weakly correlated with coverage.In the three communities in arid karst rocky mountain,E.odoratum could produce a large number and light seeds,it indicated that E.odoratum had strong reproductive capacity and displayed strong invasive,and it also could choose the corresponding reproductive strategy according to the environment change,so that it could adapt to environment at large scale.