尾巨桉S2层微纤丝角及组织比量的径向变异

Radial Variation of the Micro-fibrillar Angle and Tissue Proportion Of Eucalyptus urophylla×Eucalyptus grandis Families

对8个尾巨桉家系木材的S2层微纤丝角和组织比量进行了系统研究.结果表明:(1)S2层微纤丝角自髓心向外呈缓慢的减小趋势.(2)导管组织比量径向上呈递增趋势,随后在第5至第11生长轮间略有降低或基本保持平稳;纤维组织比量从髓心向外的数个生长轮内变异规律不明显,近树皮处有上升或下降的现象;木射线组织比量随树龄的增加而减小,以后又呈波动性的增加或基本保持稳定;轴向薄壁组织比量径向上变动幅度较大,无一定规律.(3)家系间及家系内个体间的组织比量在个体水平上分布范围较广,呈正态分布,开展个体选择的潜力大.(4)S2层微纤丝角和纤维长度间存在一定负相关,但关系密切程度比针叶材低.

The wood micro-fibrillar angle and tissue proportion of E, urophylla × E. g randis from eight families have been studied systematically. The results are as follows： （1） the micro-fibrillar angle decreases gradually from pith outward, showing a gentle trend; （2） the vessel elements proportion increases with the tree age and then decreases gradually or maintains stable between the fifth growth ring and the eleventh growth ring; the fiber proportion has no significant variation regulation among the original growth rings and increases or decreascs in fluctuation near the bark; and the ray proportion decreases annually and then increases irregularly or maintains stable while the axial parenchyma proportion takes on great fluctuation and has no certain regulation along the radial orientation; （3） the wide, individual distribution of tissue proportion among the families and within one family provides big probability and potential for their individual selection; and （4） there is a negative correlation between fiber length and micro-fibrillar angle but the correlative coefficient is lower than that of conifer.