Flowering in longan (Dimocarpus longan L.) induced by hormonal changes following KClO<inf>3</inf> applications

Abstract

Flower induction in longan (Dimocarpus longan L.) following the application of 8 gKClO3 m-2 canopy as soil drench at mature leaf stage was associated with a) increased concentrations of the cytokinins zeatin and zeatinriboside in both the bud meristem and the surrounding leaf primordia around 7 to 10 days before first flowers appeared; b) reduced leaf stomatal conductance, transpiration and net CO2 assimilation; c) a transient increase in leaf ethylene evolution, and d) lower export rates of gibberellins, auxin, abscisic acid, and zeatin and zeatinriboside from leaves. The reduced amount of auxin and gibberellins exported from leaves and typically favouring vegetative growth, in combination with increased levels of cytokinins in buds, known to support floral bud development, might play a key role in flower induction not only in longan, but also for other perennial fruit tree crops. © Verlag Eugen Ulmer KG.