泡桐侧芽萌发成枝接干规律

The Laws of Branching and Trunk Extension Sprouted from Lateral Buds in Paulownia trees

为利用侧芽进行泡桐人工接干提供理论依据,研究了自然状态下1年生泡桐侧芽萌发成枝接干规律。结果显示:1)在高密度粗放管理条件下,毛白33泡桐分枝习性表现为假二叉分枝,第2年不能接干的占42%,而58%的单株分枝特性表现为合轴分枝与假单轴分枝(近似顶芽接干的主轴分枝或单轴分枝),能够实现自然接干,这3种分枝类型可以统称为假轴分枝;2)第2年接干单株的接干形率均较大,但能不错位通直接干的仅占14%,86%的接干单株的错位状况需要2～3年后才能得到改善;3)在接干单株中,从接干的上侧芽向下数,越向下在干上分布的侧芽萌发成枝的长度、粗度越小,枯死率越高,但与主干上方夹角逐渐变大,第4对侧枝的分枝夹角最大,以下夹角减小,长度、粗度减小趋势变缓,并枯死。

In order to carry out trunk extension by lateral buds, the laws of branching and trunk extension from lateral buds ere investigated in 1-year-old seedlings of Paulownia tomentosa × P. fortunei 33 under natural conditions. The results were as follows： 1 ）The rate of individuals with characteristics of false dichotomous branching was 42% in seedlings of Paulownia tomentosa × P. fortunei 33 under conditions of high density and extensive management. They could not extend their trunks.However other individuals could do it with features of sympodial branching and false monopodial branching （Close to monopodial branching that terminal buds can extend their trunks）. These 3 types of branching all could be called branching of false axis; 2） The form quotients of extended trunk were larger but individuals which could vertically extend their trunks were only 14%,individuals of 86 % could not straightly extend in the second year, improving their straight degrees needed for 2 - 3 years; 3）The lengths and diameters of branching were smaller and smaller, but the angles from branching up to trunk were larger and larger,to the fourth lateral branches the angles reached to the largest, then smaller and smaller from upper lateral buds to down lateral buds among individuals of extended trunks. All branches under the fourth lateral branches were dead.