泡桐下侧芽萌发成枝与上侧芽萌发接干间关系

该文研究了自然状态下1年生泡桐下侧芽萌发成枝与上侧芽萌发接干间的关系.结果显示:在高密度林分的接干单株中，上侧芽萌发成枝接干与下侧芽萌发成枝间关系密切.接干侧芽的对生侧芽萌发不利于接干枝高生长，并降低接干形率；接干处向下数第1对侧芽萌发成枝倾角越小接干形率越高，第1、2对侧枝长度和粗度仅与胸径生长正相关；第3对侧枝倾角与接干处主干直径和接干基径呈负相关.增加成枝数量，减少单枝生长量，而枝长、基径合计不减少，能增大接干高度和接干处主干直径；第4对侧枝长度、粗度与主干、接干粗生长正相关；第5对侧枝长度、粗度与胸径生长正相关，而其以下侧枝对主干和接干的生长影响较小. 

College of Forestry and Horticulture, Henan Agricultural University, Zhengzhou, 450002, P. R. China.

In order to carry out trunk extension by lateral buds, the relationship between branching sprouted from lower lateral buds and trunk extension sprouted from upper lateral buds was investigated in 1_year_old seedlings of Paulownia tomentosa × P. fortunei 33 under natural conditions. The results showed that there was a close relationship between branching sprouted from lower lateral buds and trunk extension sprouted from upper lateral buds in a high density. The branching sprouted from opposite lateral buds was unfavorable to trunk elongation, and it decreased the form quotients of extending trunk. The smaller the obliquities of branching by the first pair of lateral buds were, the larger the form quotients of extending trunk were. At the same time, the growth of the first and second pairs of branching could accelerate the growth of DBH. The branching obliquities by the third pair of lateral buds were negatively correlated with the upper diameters of main trunk and the base diameter of extending trunk. The length of extending trunk and the upper diameter of main trunk increased with the increase of branching number and the dedine of single branch growth. The length and diameter of branches sprouted from the fourth pair of lateral buds were positively correlated with the diameter of the trunk，and the fifth lateral branching was correlated with DBH, while there was a little influence of lateral branching below the fifth on the growth of main trunk and extending trunk.