Primary Study on Branch Cyclophsis and Sucker Rejuvenation Effect of Populus tomentosa

The cyclophysis in flower branch gene pool of plus tree and the rejuvenated effect of clonal test plantations originated from sucker of P.tomentosa were studied in this paper.The results are shown as follows:(1) the cyclophysis is significant in growth characteristics with linear correlation on the age of plus trees, it has no effect on coal-like disease and characteristics in foliage because of no relation from 1 to 3 polynomial regressions between these characteristics and the age of plus trees, but these have 3 polynomial regressive relation in stem straightness; (2) the growth is nomal in clonal test plantations and has no relation with the originated plus trees, also not significant in variance components of age and age-class, so the sucker shows good rejuvenated effect and eliminates the age difference of plus trees.