不同生育期入侵植物大狼把草的生物量分配格局及异速生长分析

摘要

生物量分配格局和异速生长关系与植物生态策略的形成密切相关,对探讨植物对环境的适应性,揭示入侵植物的入侵机制有着重要意义.目前,对于入侵植物不同生育期之间的生物量分配格局和异速生长关系的差异研究较少.以入侵植物大狼把草(Bidens frondosa)为研究对象,采用挖掘法和称重法对大狼把草苗期、营养期和繁殖期的生长特性和生物量分配格局进行研究,并利用标准化主轴估计(standardized major axis estimation,SMA)方法对构件形态特性与生物量间的异速生长关系进行分析.结果表明:株高、植株基径、分枝数和叶片数均随着生育期的推进而增加,根长、总叶面积和平均单叶叶面积均在营养期达到最高.叶生物量分配比在苗期最大(48.88％),茎生物量分配比在生殖期最大(59.89％);苗期和营养期根生物量分配比显著高于生殖期(P＜0.05),茎生物量分配比随生育期的推进而升高,而叶生物量分配比随生育期的推进而下降,且不同生育期间存在显著差异(P＜0.05).大狼把草植株基径与各构件生物量间呈异速生长关系,总叶面积与茎、叶生物量大致呈等速生长关系,但不同生育期间、构件间的异速生长关系存在一定差异.可见,不同生育期大狼把草的生长特性、生物量分配格局及异速生长关系存在差异,显示了其灵活的生长和资源分配策略.%The relationship between biomass distribution and allometric growth is closely related to formation of plant ecological strategies,it is of great significance to understand adaptability of a plant to environment and to reveal mechanism of invasive plants invading a region.At present,not much has been reported concerning relationship between biomass distribution and allometric growth relative to growth stage of an invasive plant.A study on Bidensfrondosa,an invasive species,was carried out using excavation and weight methods to explore growth characteristics and biomass distribution of the plant at its seedling stage,vegetative growing stage and reproductive stage.And then analysis was done of allometric relations between modular morphological characteristics and biomass with the standardized major axis estimation method (SMA).Results show that plant height,base stem diameter,branch number and leaf number increased with the plant growing from one stage to the next stage,and root length,total leaf area and mean single leaf area peaked at the vegetative growth stage.Leaf peaked in biomass distribution ratio at the seedling stage period (48.88％),while stem did at the reproductive stage (59.89％).Root at the seedling and vegetative growth stages was significantly higher in biomass distribution ratio than that at the reproductive stage (P＜0.05).Stem increased in biomass distribution ratio with the plant growing from one stage to the next stage,while leaf did reversely and varied sharply with the stage (P＜ 0.05).Moreover,base stem diameter of the plant was in allometric relationships with all the other plant parameters in biomass,whereas total leaf area was in isometric relationships with stem and leaf biomass.However,the allometric relationships between tissues of the plant varied with the growth stage.Obviously,growth characteristics,biomass distribution and allometric relationships of B.frondosa vary with the growth stage,indicating its flexible growth and resource allocation strategy.