不同生境小花山桃草自然种群表型变异与协变

小花山桃草自然种群的表型特征是其对自然生境适应的结果,不同生境种群间表型特征的比较可为揭示其表型变异产生的原因及变异规律提供重要线索。本研究以分布于不同生境的5个小花山桃草自然种群为研究对象,研究了16个表型性状的变化特点。研究结果表明,小花山桃草表型多样性较为丰富,表型性状的平均变异系数为36.30%。表型分化系数在26.85%~96.98%之间,平均为73.03%,表明种群间变异是小花山桃草表型变异的主要来源。不同性状对环境变化的反应不同,其中株高、茎粗、单株果数和比叶面积在种群内的差异不显著,而在种群间的差异达到极显著水平,表型分化系数达82%以上;节间距、叶宽、主根长、分枝数、果长和果宽在种群间和种群内的差异均达极显著水平;单果种子数和单果重在种群内和种群间的差异均不显著。株高、茎粗、叶长、叶宽、茎重、叶重、主根重和单株果数表现出一致的协变格局,生理功能性状之间的这种整合特性有助于小花山桃草适应多样的生境。聚类分析显示,5个种群可按生境条件的好坏分为两大类,进一步表明小花山桃草的表型特征受种群间环境条件(水、肥)强烈影响。绝大多数表型性状与生境因子存在显著或极显著的相关关系,但果实性状(包括果宽、单果重和单果种子数)与生境因子相关性低,进一步表明繁殖性状不易受环境条件影响。

Phenotypic variation and covariation in natural populations of the exotic weed Gaura parviflora in different habitat

Phenotypic traits of the natural Gaura parviflora population represent its adaptation to natural envi-ronments.Comparison of phenotypic traits among different populations can provide important clues for under-standing phenotypic variation and formation processes of G.parviflora.We investigated 16 phenotypic traits in 5 G.parviflora populations located in the coal-gangue pile of Yima and compared variations in phenotypic traits in natural conditions.Our results showed that the average variation coefficient of phenotype traits was 36.30%,which indicated the comparatively abundant phenotypic diversity in G.parviflora.The phenotypic differentiation coefficients (V st )ranged from 26.85% to 96.98%,the mean value was 73.03%,which indica-ted that the variance among populations was the main part of the phenotypic variation.Different traits respon-ded differently to environmental changes.Plant height,base stem diameter,number of fruit per plant and spe-cific leaf area were similar among individuals within a populations,but differed from each other significantly a-mong populations.The phenotypic differentiation coefficients (V st )of them were more than 82%.There were significant differences in the phenotypic traits of internodal space,leaf width,root length,branch number, fruit length and fruit width among populations and among individuals within a population.Number of seeds per fruit and single fruit weight were similar among populations and among individuals within a populations.Plant height,base stem diameter,leaf length,leaf width,stem biomass,leave biomass,root biomass and number of fruit per plant showed a consistent integration pattern,which helped to increase the ecological adaptation of G. parviflora.Cluster analysis showed that different populations from the similar habitat conditions grouped to-gether,further showing that the phenotypic traits of G.parviflora were strongly influenced by the habitat fac-tors.The correlation analysis showed that the majority of phenotypic traits significantly correlated with habitat factors,while the fruit traits (fruit width,single fruit weight and number of seed per fruit)did not,which in-dicated that reproductive traits were not influenced by the environmental factors.