入侵植物银胶菊在不同生境下表型可塑性和构件生物量

研究了入侵植物银胶菊在4种不同小生境间花果期形态特征变化和构件生物量特征。结果显示:在植株密度小但土壤肥沃的小生境中,植株各形态指标如茎长、茎直径和花序直径等都明显高于其它小生境,在生物量结构特征上则表现为总生物量和花果生物量所占比例的升高。随着植株密度的增加以及土壤肥力下降,上述各形态指标都发生了较明显的变化,生物量投资也进行了优化配置,银胶菊表现出了较高的形态可塑性。银胶菊与觅光和竞争相关的几个指标如叶和根的比例都增加,但用于生殖构件的比例却减少了。相关分析显示,银胶菊花果期各构件生物量与高度成正相关,与密度为负相关,并受环境因素的制约。表明,较高的形态可塑性和较强的生殖配置策略可能是银胶菊成功入侵我国的重要特征。

Phenotypic plasticity and modular biomass of invasive Parthenium hysterophorus in different habitats in south China

Parthenium hysterophorus is a worldwide weed. In this paper,we compared the phenotypic plasticity and modular biomass among microhabitat types(farmland,grassland,forest edge and roadside),in a village community alone a road in the autumn of 2008,to answer the two specific questions that:1)phenotypic plasticity may have played a key role in adaption to diverse habitats of P.hysterophorus;and 2)reproductive allocation must have adjusted to adaption diverse habitats. The results indicate that several morphological traits including stem length,stem diameter,inflorescence diameter and branch number of P.hysterophorus were significantly higher in farmland than others,and the proportion of biomass including flower and fruit,stem in farmland habitat have ranked the highest. With vary of the habitats soil fertility,plant density of P.hysterophorus decreased,all the morphological traits have showed a wide range. And biomass allocation proportion of function modules of P.hysterophorus have also made an optimized allocation to fit the varied habitats,for example,biomass of root and leaf related to light foraging and resource competed creased significantly from farmland and roadside to grassland and especially forest edge habitats. Correlation analysis indicated that there were significant positive correlations between the biomass of function modules and stem length,but significant negative correlations between the biomass of function modules and density. The results suggest that high plasticity and strong reproduction allocation in vertical growth may facilitate the invasions of P.hysterophorus.