极小种群野生植物梓叶槭的种实表型变异特征

表型变异是植物遗传变异与环境异质性相互作用的结果, 是植物适应和进化的具体表现。为揭示极小种群植物梓叶槭(Acer catalpifolium)的种实表型在其适应环境过程中的变异特征, 明确梓叶槭优质种源地, 为该物种的保护提供基础数据, 本研究以天然分布的5个小种群的11个种实性状为研究对象, 采用巢式方差、变异系数、表型分化系数等多种指标, 探讨了其种群间和种群内的表型变异。结果表明: 梓叶槭种实表型性状在种群间和种群内均存在着显著的差异, 种群内的变异(63.11%)大于种群间的变异(23.61%), 种群间平均分化系数为27.23%, 分化程度在槭树科植物中相对较大。种子厚度的平均变异系数最高(40.64%), 其次是果柄长。翅果千粒重的平均变异系数最小(1.57%), 是最稳定的种实性状。都江堰种群的表型多样性最丰富, 平武种群的则最低; 气象因子对梓叶槭种实表型性状的影响不显著。就种实表型性状而言, 虽然雷波种群的翅果最大, 平武种群的种子最大, 同时两者均具有最大的种子厚度和质量均一度。故平武和雷波种群均可作为梓叶槭优质种质资源的候选地。

Phenotypic fruit and seed variations of Acer catalpifolium,a Wild Plant with Extremely Small Populations in China

Phenotypic variation can indicate the adaptation of plant species to different environmental conditions due to long-term evolution. Acer catalpifolium is a relatively primitive species in Aceraceae family, and is a rare and endangered species in China. To understand the range of phenotypic variation of A. catalpifolium’s fruits and seeds, 11 traits for 47 individuals from five natural small populations of A. catalpifolium were measured and parameterized using coefficients of variance, variation, and correlation. The results showed significant differences in phenotypic variation among and within populations. Overall variation was greater within population (63.11%) than among populations (23.61%) while the mean phenotypic differentiation coefficient was 27.23% among populations, larger than other species in Aceraceae. The average variation coefficient of seed thickness (ST) was the highest (40.64%), followed by fruit stalk length (FSL); thousand-fruit weight (TFW) was the smallest and the most stable phenotypic trait (1.57%). The Dujiangyan population has the highest phenotypic diversity and Pingwu population the lowest. Meteorological factors were not associated to fruit and seed size variations of A. catalpifolium. The fruits of the Leibo population were largest while the seeds of Pingwu population were the biggest. These two populations also have the thickest seeds. Fruit/seed size is considered as an indicator of quality, because bigger fruit/seed could provide more nutrients for next generations, therefore, the Leibo and Pingwu populations should be the priority when collecting germplasms of A. catalpifolium.