不同种源麻栎种子和苗木性状地理变异趋势面分析

麻栎(Quercus acutissima Carr.)是优良的能源和用材树种,在我国分布广泛并已有悠久栽培利用的历史,研究其种子和苗木性状地理变异规律对选择优良种源和适生区十分必要.研究收集了13个省(区)36个种源的麻栎种子,在测定麻栎种子性状的基础上,在安徽省滁州市红琊山林场进行了苗期试验和苗木性状测定,并采用趋势面分析方法对这些性状在经纬2维方向的地理变异模式进行了剖析.结果表明:1)麻栎种源间种子长度、宽度、百粒重和营养内含物存在极显著差异.种子百粒重、长度和宽度总体表现双向渐变趋势,随经度增高而增大,随纬度增高而减小,主要受到经度的控制;以西南到东北为中间地带,可溶性糖含量向东南表现先下降后上升的趋势,向西北则相反;淀粉含量从西北到东南呈逐渐减小的趋势.2)麻栎种源苗高、地径、生物量、热值和木材化学组分存在极显著差异.苗高、地径和生物量均呈双向渐变,经正向变异且变化幅度较大,纬负向变异且变化幅度较小,经度影响大于纬度;热值拟合回归方程不显著,方程无意义.木质素含量北部大于南部,但北部以西北部最高,南部以东南部最高.3)研究显示,麻栎种子和苗木性状多数存在显著的地理变异模式,这也是麻栎在长期进化过程中为适应复杂多变的环境而产生与之相适应的遗传变异结果.

A trend surface analysis of geographic variation in the triats of seeds and seedlings from different Quercus acutissima provenances

Quercus acutissima, widely distributed in china, is one of the most important hard broadleaf species for wood charcoal and wood production. Because of its high calorific value and excellent wood properties, the species not only has been cultivated and utilized for a long time in China, but also has been focused on forestry bioenergy recently. However, there has been seldom study so far that have investigated variations in seed and seedling traits of Quercus acutissima from different provenances. In order to select the superior provenances for suitable distribution areas, it is very important to study the geographic variation pattern and ecological basis of seed and seedling from different provenances of Quercus acutissima. Thirty-six Quercus acutissima provenances were collected from 13 Provinces in this study. Based on the measurement of seed traits, the trial of seedlings from 36 provenances was established at Hongyashan Forestry Farm in Anhui Province and the seedling traits were measured. Moreover, the geographical variations of seeds and seedlings from the 36 provenances were analyzed by trend surface analysis in two dimensions of latitude and longitude on the basis of data collected. The main results were as follows: 1) There were significant differences in length, width, weight per 100 seed and nutrient contents (soluble sugar, starch and protein) among the seeds from different Quercus acutissima provenances. Geographic variation pattern of seed length, seed width and 100-seed weight showed a bidirectional trend, and the variations were mainly subjected to longitude, e.g. seed length, seed width and 100-seed weight increasing with the increase of longitude, while decreasing gradually with the increase of latitude. Considering southwest to northeast as the intermediate zone, content of soluble sugar showed a decrease and then increases trend toward southeast, while showed a contrary tendency toward northwest. Content of starch also showed a bidirectional trend, e.g. decreasing gradually form northwest to southeast. In a word, the influence of latitude on seed traits was greater than the longitude. 2) There were significant differences in seedling height, ground diameter, biomass production, calorific value and wood chemical compositions among the different Quercus acutissima provenances. The regression equation of binary quadratic trend surface of seedling height, ground diameter and biomass were satisfied with the statistical requirement. However, the regression equation trend of surface for calorific value was not significant, and the regression equation of three powers contour-trend surface of lignin could simulated geographic variation tendency. Geographic variation pattern of seedling height, ground diameter and biomass showed a bidirectional trend. The positive variation was observed in longitude, while negative variation was detected in latitude. The effect of latitude to seedling growth was greater than the longitude. The lignin content in the woods from the northern provenances was higher than that from the southern due to the effect of longitude. 3) Results from this research indicated that there existed a significant geographic variation pattern for most measured traits of seeds and seedlings, which is the results of species evolution and genetic variation of Quercus acutissima in order to adapt to complicated variable environments Compared with traditional method, trend surface analysis could collect nonlinear information and more finely described genetic variation trend of different provenances which would not obtained from the linear correlation analysis.