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Study on the mechanisms of flower bud induction in apple tree

Li Tianhong, Huang Weidong, Meng Zhaoqing

College of Plant Science and Technology,Beijing Agricultural University.Beijing 100094

Abstract

Five-year-old ‘Red Fuji’apple tree (Malus domestica Mill.) were used as materials to test for the effect of treatments of paclobutrazol (Pacl.), girdling, girdling+Pacl. and GA_(3) on the contents of nitrogen and carbohydrates in spur leaves and of endogenous hormones in buds. The results showed that the effects of the treatments to increase flower bud formation were in the order of girdling+Pacl. (+648%)>girdling (+534%)>Pacl. (+154%). At the beginning of flower bud induction, the contents of IAA and ZR (Fig.4), and ratio of IAA/GA_(s) or ZR/GA_(s) (Fig.5) were significantly increased in spur buds, while the ratio of IAA/GA_(s) with various flower-promoting or-inhibiting treatments were much higher and was correlated with the percentage of flower bud formation. ZR/GA_(s) ratio, however, was negatively correlated with the percentages of flower formation of which girding treatment, giving high percentage of the flower formation resulted in a lower ZR/GA_(s) ratio than treatment with Pacl., which gave a low percentage of flower bud formation. At the completing phase of flower bud induction, starch content and C/N ratio (Fig.3) and the contents of ZR and IAA, and ZR/GA_(s) ratios in spur bud were remarkably increased, while GA_(s) content in spur bud was decreased by girdling+Pacl., girdling and Pacl. treatments. The above parameters for all the flower-promoting or-inhibiting treatments were changed in the opposite direction to the percentage of flower formation, except the C/N ratio.

Key words: Apple;Mechanisms of flower bud induction;Endogenous hormone;Nitrogen and carbohydrates contents

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Citing This Article：

Li Tianhong, Huang Weidong, Meng Zhaoqing. Study on the mechanisms of flower bud induction in apple tree. Acta Physiol Sin 1996; 48 (3): (in Chinese with English abstract).