Growth Characters and Its Allometric Relationships of Taxus yunnanensis Saplings from Different Sprouts Types

The growth characters and its correlation and comprehensive index value of 4-year-old Taxus yunnanensis saplings form different sprout types in Mingxi, Fujian were investigated and revealed their genetic variation, the allometric relationship was analyzed by standardized major axis analysis, and to analyze adaptive strategy of T. yunnanensis saplings from different sprouts types. The results showed that the saplings height and ground diameter of stem epicormic sprouts type were significantly higher than those of non sprouts and stem basal sprouts types, and the crown width, lateral branch number and comprehensive index value of stem epicormic sprouts type and stem basal sprouts type were significantly higher than those of non sprouts type. The correlation between saplings ground diameter, height and crown width among different types were different. The allometric exponent index of ground diameter and tree height of non sprouts type was significantly greater than 1, while growth relationships of stem basal sprouts and stem epicormic sprouts types were isometric, the allometric exponent index of crown width and tree height of different sprout types were significantly greater than 1. The allometric exponent index of lateral branches number and tree height of non sprouts and stem basal sprouts types were significantly greater than 1, while growth relationships of stem epicormic sprouts type was isometric. The allometric exponent index of lateral branches number and tree height of non sprouts type were significantly higher than those of stem epicormic sprouts and stem basal sprouts types. The ground diameter and tree height, crown width and tree height of Taxus yunnanensis different sprouts types saplings exhibited a common allometric exponent of 1.150 and 1.658, respectively. The seedlings of different sprouts types had both isometric and allometric relationships. There were significant differences on growth characters and its correlation of T. yunnanensis saplings from different sprouts types, indicating that there were abundant genetic variation.There is no consistency allometric growth relationship among different sprouts types, it represents the growth and adaptation strategies of different sprouts types saplings. It was suggested that stem basal sprouts and stem epicormic sprouts types should be adopted to develop the taxane raw material forest.