中文摘要：

外来植物入侵对生物多样性和生态系统稳定性具有严重威胁,为阐明互花米草（Spartina alterniflora）在闽东滨海湿地入侵机理,分析影响互花米草表型可塑性的因素与其成功入侵之间的关系,选择闽东滨海湿地潮间带6条断面,研究不同潮位生境互花米草种群形态特征、无性繁殖特征、有性繁殖特征以及生物量积累和分配格局.结果表明,潮位梯度对互花米草形态特征和有性繁殖特征有显著性影响（P〈0.05）,对互花米草无性繁殖影响不显著（P〉0.05）;株高、茎粗、叶长等形态指标在高潮位（S6）处均显著大于其他潮位生境,但中潮位和低潮位整体上无显著差异;潮位变化对互花米草种群密度影响不显著,互花米草种群入侵速度放缓,说明尽管互花米草有性繁殖可塑性很强,但繁殖效率低下;而无性繁殖表型可塑能力差可能就是解释互花米草种群10年来在闽东滨海湿地入侵缓慢甚至趋于稳定的原因之一;潮位梯度对互花米草生物量积累有极显著影响（P〈0.01）,样地S6地上生物量和地下生物量均显著高于其他样地,对互花米草生物量分配有一定影响,但没达到显著性水平.总之,互花米草更适应高潮位生境,生境＂觅养＂能力与有性繁殖能力更强.

英文摘要：

Spartina alterniflora is a world-wide notorious invasive species that has colonized large areas in coastal China since it was introduced in 1979. Its powerful genetic differentiation ability and resistance to adversity contribute to its invasiveness. For a comprehensive understanding of the mechanism of plant invasion, the ecological strategy of exotic plants as a result of resources and environmental difference is needed to be known. This paper aimed to study Spartina alterniflora morphological plasticity and biomass allocation in response to tidal gradient change in Mindong coastal wetlands, China. Spartina alterniflora morphological variation, asexual reproduction, sexual propagation and biomass distribution characters at six transects of the intertidal zone in Mindong coastal wetlands were investigated by field investigation and laboratory analysis. The results showed that tide level gradient had significant effects on morphological variation and sexual propagation of Spartina alterniflora（P 0.05）,but had no significant effect on asexual reproduction（P 0.05）. The morphological indices of Spartina alterniflora including plant height, stem diameter, length of leaf were significantly higher at high tide level（S6） than the middle and lowtide level, with the differences between the middle and low tide levels not significant. The tide level gradient had no significant effect on population density of Spartina alterniflora（P 0.05）. The intrusion of Spartina alterniflora slowdown in the past 10 years indicated that its sexual reproductive efficiency was very low in spite of the strong plasticity of sexual reproduction. One reason of the slowdown in intrusion of Spartina alterniflora was probably the poor phenotypic plasticity in asexual reproduction of Spartina alterniflora. Tide gradient had significant effects on biomass accumulation of Spartina alterniflora（P 0. 01）, with the aboveground biomass and belowground biomass of S6 significantly higher than other plots. Tide gradient had effects on bio