Sensitivity to Abscisic Acid and Gibberellines During Dormancy Establishment of Lily Bulblets in Vitro

ABSTRACT

The sensitivity to ABA or GA₄₊₇ was measured in bulblets of Lilium speciosum regenerated on scale explants in vitro at temperatures (15, 20 and 25°C) that allowed development of various levels of dormancy. ABA content at the time of bulblets sprouting did not correlate with dormancy development. Sensitivity to ABA or GA₄₊₇ was defined as the difference in sprouting of excised bulblets on medium with or without the above hormones. The sensitivity to ABA decreased with temperature of regeneration and age of bulblets. In bulblets on ABA-containing medium, the ABA content was always higher. Quite inexpectedly, on GA₄₊₇ containing medium, the ABA levels were lower that those on control medium. It was concluded that the sensitivity to ABA plays a key role in dormancy development. Studies on factors other than ABA or GA should be carried out further to clarify the dormancy phenomena.