| Chrysanthemum (Chrysanthemum morifolium) is the traditional famous flower of China, and it is also one of the four most important cutting flowers all over the world. Autumn-cutting chrysanthemum'Jinba'is one of the main cultivars for exporting in our country. To cultivate them all year round, the key is to control the florescence. But the studies on flowering regulation was limited. Recently we've found that Salicylic acid and hormones were closely related to the foral bud differentiation. In this trial we studied the changes of endogenous hormones in the apical buds and leaves and how the different concentrations of SA (0, 10, 50, 100, 150μmol/L) affected the floral bud differentiation and florescence, as well as appearance quality under short-day treatment. Then we could know which role did the SA and hormones played in the floral bud differentiation, and identify what is the best concentration to promote the florescence and appearance quality. It will be benefical to export chrysanthemum'Jinba'with high quality.The main results were as follows:1. The flower bud differentiation, which included 9 stages, lasted 27 days with short-day treatment. The results showed that GA3 contents in apical bud decreased and stayed at a low level in most of the time, however, the changes of GA3 contents in leaf were the contrary to the apical bud. The IAA contents in apical bud decreased first and reached the minimum value at the initial stage of floret primordia differentiation, and then reached the maximum value at the metaphase stage of crown formation. The IAA contents in leaf showed an increasing tendency before the initial stage of involucre primordia differentiation, then decreased later, and changed to be steady until the stage of crown formation. The contents of CTK increased greatly and were higher than those at the vegetative stage. The ABA contents in apical bud decreased first and then showed an increasing tendency, while ABA contents in leaves increased first and showed a decreasing tendency after a short steady period. The ratios of CTK to IAA, CTK to GA3, ABA to IAA and ABA to GA3 increased after flower bud differentiation started.2. The flower bud differentiation and flowering process of chrysanthemum were accelerated by treated with 10, 50, 100 and 150μmol/L SA, and the treatment with 50μmol/L SA was showed the best result among these treatments. Compared with the CK, the days of the flower bud differentiation were decreased 6 days, the visible buds stage, the flower bud broking stage and the flower opening stage were showed 5 days, 8 days and 8 days earlier respectively, and the blooming times was prolonged 5 days in the treatment with 50μmol/L SA. Otherwhile, the vase life and the appearance quality were highly improved by treated with different concentrations of SA, and the treatment of 100μmol/L SA showed the better result compared with other SA treatments (0, 10, 50 and 150μmol/L SA).3. During floral induction period, the chrysanthmums were treated with the 50μmol/L SA, the GA3 contents in apical buds, which were contrary to the leaves, were decreased; the IAA contens in apical buds decreased more than the CK; the CTK contents in apical buds and leaves were increased more than the CK; the ABA contents in apical buds decreased firstly and then showed an increasing tendency, while ABA contents in leaves increased firstly and showed a decreasing tendency. The ratios of CTK to IAA, CTK to GA3, ABA to IAA and ABA to GA3 increased significantly with 50μmol/L SA treatment.4. The contents of soluble suger, starch, protein and nucleic acid in apical bud and leaves of chrysanthemum, which were the essential nutrient elements during growing and developing, were increased during floral induction period by treated with 50μmol/L SA. At the same time, the activity of NR and PAL in apical bud and leaves of chrysanthemum were increased. The free SA contents were constantly increasing, while the conjugated SA contents were decreasing in the leaves of the plants.
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