青钱柳天然群体间木材微纤丝角的地理变异趋势

【目的】青钱柳是我国特有的单种属植物,是一种很有开发利用前景的珍贵树种。研究青钱柳木材微纤丝角变异规律,可为用材林优良基因筛选提供依据。【方法】以不同地理分布的青钱柳种源为研究对象,通过钻取木芯并采用X-射线衍射法探讨了青钱柳木材微纤丝角的地理变异的和径向变异规律。【结果】22个青钱柳地理种源木材微纤丝角存在显著差异。21年生木材平均微纤丝角为15.8°,变异幅度在13.4°～20.1°。其中四川沐川种源的平均微纤丝角最小,比22个种源微纤丝角的平均值低15.2%,广西桂林种源的平均微纤丝角最大,高出所测试种源平均值27.2%。青钱柳微纤丝角受经度和纬度双重因素影响,在经度上以112°E为中心,向东西两边递减; 在纬度上呈现出以29°N为中心,向南北两边递增的趋势。随着生长轮年龄的增大,微纤丝角呈现递减的变化趋势,用指数曲线描述微纤丝角与树龄的回归关系最为合适。【结论】多重比较结果表明,15年生后青钱柳木材微纤丝角趋于稳定,可作为青钱柳用材林优良基因型筛选的依据之一。

A study on geographic variation in wood microfibril angle of Cyclocarya paliurus

Abstract: 【Objective】Cyclocarya paliurus, the sole species in its genus, is a highly valued tree species with multiple functions in China. Studies on the variation of the microfibril angle of the wood of Salix. Salix can provide a basis for the selection of C. paliurus genotypes in timber forests. 【Mothed】 Based on the wood cores sampled from different natural populations, geographic variation and growth ring variation in wood microfibril angle(MFA)of C. paliurus were investigated using the X-ray diffraction technique. 【Result】 Significant variation was observed among 22 C. paliurus provenances and growth rings. Mean MFA at the breast height was 15.8° for all tested provenances, ranging from 13.4° to 20.1° when the tree age was 21 years. The wood of the Sichuan Muchuan population showed the lowest MFA, while the highest MFA was observed in Guangxi Guilin. Compared with the mean value of the 22 provenances, the MFA of Sichuan Muchuan decreased by 15.2%, but increased by 27.2% for Guangxi Guilin vs CK. The MFA of C. paliurus is affected by both latitude and longitude, and the geographic variation decreased on both sides, that is the East and West of the central longitude, 112° E, but increased on both sides, that is, the South and North of the central latitude, 29° N. MFA at breast height significantly varied among the growth rings, with a consistent pith-to-bark trend of declining angles. The relationship between MFA and growth ring could be best described by an exponential function. 【Conclusion】 Our results indicated that the MFA was relatively stable after 15 years, suggesting that there exists a great opportunity to improve wood quality of C. paliurus through selection of trees with low MFA.