Effect of Scaling Date on Leaf Emergence and Endogenous Plant Hormone Levels in Hyacinth (Hyacinths orientalis L.)

Leaf emergence from bulblets during scaling in hyacinth (Hyacinthus orientalis L.) was affected by stage of dormancy. It occurred in the post-dormancy stage, at the end of the period of high summer temperature, but not in the pre- (during winter) and true-dormancy (flowering and bulb maturing periods) stages. Changes in plant hormone levels in the scales and basal plates of mother bulbs were synchronized with these phenomena, i. e. auxin activity was high in the post-dormancy stage and then decreased while abscisic acid activity was detected during the period from pre- to true-dormancy. It was recognized that the induction of dormancy in hyacinth is caused by low temperature. Close relationship between the phenomenon of the induction of dormancy in autumn planting bulbous plants and the induction of bulb formatin is suggested