Abstract: An orthogonal design was used to assess the influence of gibberellin and amino acid on branch and leaf growth of Syzygium grijsii. The results showed: the growth curve of S.grijsii was a double-peak type, there were two growth peaks in spring and autumn, respectively. There was significant interaction between gibberellin and amino acid, which had promotion effects on the branch and leaf growth of S.grijsii. Most observed variance of growth was obviously affected by the concentration of gibberellin acid whereas amino acid had a little effect. For branch and leaf growth, 100 mg·L^-1 was an appropriate concentration of gibberellin acid. Concentration variance of exogenous nutrient had a larger effect on young tissues like new shoot and new branch than those old ones. Principal component analysis(PCA) showed mean month growth of new shoot and number of new branch would be considered as rapid indices for evaluation of gibberellin and amino acid spraying effect. Leaf thickness and leaf area(second principal component) would be considered as potential indicators for long-term evaluation of spraying effect. Growth amount of new shoot and number of new branch would be used as fast indicators for evaluation of gibberellin and amino acid spraying effect in production.

Key words: Syzygium grijsii, amino acid, gibberellin, growth of branch and leaf