广东阳春市猪血木不同居群种实表型性状变异及萌发特征研究

Phenotypic Variations in Seed and Fruit Traits and Germination Characteristics of the Wild and Cultivated Populations of Euryodendron excelsum in Yangchun, Guangdong

摘要:

为明晰极小种群野生植物猪血木(Euryodendron excelsum)在小居群间的种实表型和萌发特性变异及其规律，了解影响发芽率的表型特征并初选优良种质。采用野外调查与室内分析等方法对广东省阳春市猪血木6个居群的种实特性和发芽率进行研究。结果表明，猪血木7个种实表型性状及发芽率在各居群间均有显著差异(P<0.05)，种实平均变异系数为32.18%，种子性状的变异程度比果实性状更丰富，其中横径、纵径、果实大小指数和百粒果重是评价猪血木居群的主要指标，野生居群的变异程度普遍高于人工居群。各居群平均发芽率为32.2%，种子生活力水平较低；其中野生居群的发芽率与果实横径、纵径、果实大小指数和果百粒重呈显著正相关，与果形指数呈显著负相关(P<0.05)，人工居群中各性状间普遍不相关。6个居群按照起源类型和地理位置可聚类为野生居群和人工居群2类，其中人工居群的种实性状普遍优于野生居群。人工居群中又以鹅凰嶂居群种实性状最优，野生居群中以八甲中部居群种实性状最优，有较高的发芽率。猪血木各个居群间种实表型变异丰富，野生居群的种子发芽率与种实表型显著相关，八甲中部居群应作为保护与利用的重点群体。

Abstract:

To clarify the variation and patterns of seed and fruit phenotypes and germination traits among extremely small populations of the endangered plant Euryodendron excelsum, and to identify phenotypic traits affecting germination rate, and select superior germplasm, the reproductive traits and seed germination rate of 6 populations of E. excelsum in Yangchun City, Guangdong Province were studied using field survey and laboratory analyses. The results showed that there were significant differences in 7 seed and fruit phenotypic traits and germination rate among populations (P<0.05), with an average coefficient of variation of 32.18%. The variation degree of seed traits was more abundant than that of fruit traits. The diameter, length, size index and 100-fruit weight of fruit were main indicators for evaluating populations. Wild populations generally exhibited greater variation than artificial ones. The overall mean germination rate was 32.2%, indicating low seed vigor. In wild populations, germination rate positively with diameter, length, size index, and 100-fruit weight, and negatively correlated with fruit shape index (P<0.05); while there was no significant correlations among the traits in artificial populations. The six populations could be clustered into two categories according to their origin type and geographical location: wild populations and artificial populations. Among them, the seed and fruit traits of artificial populations were generally better than those of wild populations. Among the artificial populations, the population of E’huangzhang had the best seed and fruit traits, and among the wild populations, the population of middle Bajia had the best seed and fruit traits and the highest germination rate. There was rich variation in seed and fruit phenotypes among the populations of E. excelsum. The seed germination rate of wild populations was significantly correlated with seed and fruit phenotypes. The population of middle Bajia should be the key population for protection and utilization.