ISHS Acta Horticulturae 653: IX International Symposium on Plant Bioregulators in Fruit Production
EFFECT OF LEAF AGE ON THE RESPONSE OF FLOWER INDUCTION AND RELATED HORMONAL CHANGES IN LONGAN TREES AFTER KCLO3 TREATMENT |
| Authors: | M. Hegele, D. Naphrom, P. Manochai, A. Chattrakul, P. Sruamsiri, F. Bangerth |
| Keywords: | auxin, carbohydrate reserves, cytokinins, Dimocarpus longan, IAA, GAs, mature leaf, plant hormones, photosynthesis, young leaf |
| Abstract:
Although experiments have confirmed that KClO3 treatment could promote flower induction (FI) in longan trees almost year round, this method seemed to be less effective in the presence of young leaves. After experimental prove of this loss in effectiveness we tried to find out whether KClO3 causes changes in longan trees that could account for this transition from vegetative to the generative buds. Therefore the influence of KClO3 application on photosynthesis in leaves and endogenous hormone levels in terminal buds was investigated. Furthermore diffusible and endogenous hormones of young and mature leaves were compared in order to see whether the flower inhibiting signal, originating from juvenile leaves, might be one of the known plant hormones. As a result we could show that KClO3 treatment caused a significant reduction in photosynthesis for about 10 days after application. This contradicts the hypothesis of carbohydrate reserves being a decisive factor in FI. Consistently lower auxin and higher cytokinin values, detected in buds of treated trees, might be prerequisites for FI. Higher endogenous IAA concentrations, detected in young leaves might lead to the almost doubled IAA export compared to mature leaves, which might prevent the efflux of IAA from the buds by “autoinhibition”. IAA could be a signal sending a message from leaves to the buds. | |
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