EFFECT OF SHOOT BENDING ON ENDOGENOUS AUXIN AND CYTOKININ LEVELS IN BUDS, AND ITS POSSIBLE RELATIONSHIP TO FLOWER BUD FORMATION IN JAPANESE PEAR

Shoot bending (30-45°) is known to accelerate flower development in Japanese pear, and here it is shown that this acceleration of flower development is accompanied by notable changes in endogenous hormone levels in the lateral buds.
Indole-3-acetic acid (IAA) concentration in the lateral buds on vertical shoots increased in mid-July, but that in the bent shoot remained nearly constant.
On the other hand, the concentrations of zeatin-type cytokinins in buds were higher in bent shoots than vertical shoots.
Additionally, when maleic hydrazide, an anti-auxin, was applied to the pear shoots at 2,600 mg L^-1, zeatin, zeatinriboside, and isopentenyladenine levels in lateral buds were increased whereas isopentenyladenosine concentration was decreased.
Thus, it is supposed the depletion of the level and/or the activity of auxin in shoot tissues is responsible for the increase of bioactive cytokinin concentration in lateral buds.
It is proposed that these changes of endogenous hormones may be involved in the acceleration of the lateral bud development.

IX International Symposium on Plant Bioregulators in Fruit Production

A. Ito, H. Yoshioka, H. Hayama, Y. Kashimura

shoot bending, flower development, indole-3-acetic acid, vertical shoot, cytokinins, maleic hydrazide, zeatin

https://doi.org/10.17660/ActaHortic.2004.653.6