木荷苗木性状的种源变异和地理模式

Provenance Difference and Geographic Variation Pattern for Seedling Trait of Schima superba

利用来自7省区36个木荷种源在浙江淳安和福建建瓯两试验点的苗期测定材料,研究其苗木生长、根系特征和叶片形态等12个性状的种源差异及其地理变异模式。方差分析结果显示,除主根长、侧根长和叶片颜色在种源间无显著差异外,其它性状的种源效应都达到显著或极显著水平。种源苗木性状与产地地理气候因子的相关分析发现,苗高、叶片特征(叶片数、叶片宽、叶片厚)及秋末嫩叶颜色等呈典型的纬向变异模式,产地温度则是造成这种纬向变异模式的主要环境作用因子。与北部种源比较,南部种源生长快,叶片数量多,但叶片较薄较窄,其秋末嫩叶颜色变化对寒冷信号反应敏感。影响木荷种子性状表型差异的主导因素是产地的年降水量。以苗高为标准,分别在两地点初选出优良种源10个,它们多来自25°N左右的木荷自然分布区。

Schima superba provenance trails including 36 seed sources from 7 provinces, located at Chun'an City of Zhejiang and Jianou City of Fujian, were used to study geographic variation for 12 seedling characteristics (seedling growth, root character and leaf shape,etc.).The result of variance analysis indicated that there existed significant differences among provenances for nine seedling traits except for taproot length, lateral root length and aged leaf color in late autumn. A classical latitude clinal variation pattern was found for seedling height, leaf character (number, width, thickness), and tender leaf color in late autumn, and the local temperature of seed sources was the main climatic factor which led to the variation pattern. Compared with the northern provenances, the southern ones had higher growth rate and more leaves, however,the leaf became thinner and narrower. Color change of tender leaf of southern provenances was sensitive to cold signal in late autumn. In addition, the precipitation amount of seed sources was main factor effecting phenotypic differences of seed traits. At last, recommended for seedling height, 10 superior provenances were selected respectively for two experimental locations and these provenances almost came from the natural distribution area about at latitude 25° N.