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应用多变量分析方法,对14个不同地理种群的细叶桉(Eucalyptus tereti-cornis Sm.)的116份腊叶标本和620株实生苗的各种性状的地理变异进行了研究。这些地理种群代表该种从巴布亚新几内亚到澳大利亚大陆南缘的整个自然分布区,此外还包括1个印度栽培种群,即“迈索尔杂种桉”(Mysore Gum)。研究发现,该种某些性状的地理变异模式与地理纬度之间存在相关性。这些变异是对环境因子的变化所产生的反应,特别是年平均温度。在同一生长条件下所培育出的实生苗,在形态特征和生长速率方面都表现出显著差异。实生苗性状变异程度大于成年大树各种性状的变异。实生苗的变异模式可能反映不同地理种群的基因型变异。但是,研究表明,细叶桉的地理变异来源,既来自地理种群的生态趋异,也来自该种与其近缘种的种间杂交。印度栽培的“迈索尔杂种桉”很可能是引自悉尼以北,昆士兰州南部以南的地理种群的细叶桉。
Using multivariate analysis, the geographical variations of 116 tracheids and 620 seedlings of Eucalyptus tereti-cornis Sm. From 14 different geographical populations were studied. These geographical populations represent the entire natural area from Papua New Guinea to the southern margin of the Australian continent, as well as one Indian cultivated population, Mysore Gum. The study found that there is a correlation between the geographical variation pattern of some traits and geographical latitude. These variations are responses to changes in environmental factors, especially the annual average temperature. The seedlings grown under the same growth conditions showed significant differences in morphological characteristics and growth rate. The variation degree of seedling traits is greater than the variation of various traits of adult tree. Variation patterns of seedlings may reflect genotypic variation among different geographic populations. However, studies have shown that Eucalyptus urophylla geographical variation sources, both from the ecological diversity of geographical populations, but also from the species and its related species of cross-species hybridization. Indian-cultivated “Mysore Hybrid Eucalyptus” is most likely the eucalyptus umbellatus that is geographically clustered north of Sydney and south of Queensland.