Changes of Endogenous Growth Regulators, IAA and ABA, During Bulb Vernalization of Lilium LA Hybrid "Ceb Dazzle"

Lilium is a bulbous plant species that requires a period of low temperature for proper growth and flowering. This experiment was conducted for studying the effect of bulb cooling on vegetative and reproductive characteristics and also study of changes of endogenous IAA and ABA levels during bulb vernalization of Lilium LA Hybrid cv. Ceb Dazzle during 2008-2009. In this experiment bulbs were vernalized for 0, 2, 4, 6, 8 and 10 weeks at 5oC. Results showed that bulbs that received no cold treatment, produced no flower. Thus in this cv. Vernalization is essential for flowering. Increases of cold duration was reduced both leaf number and bulb germination time, and increased flower number and plant height. Results also showed that during cold treatment, ABA content of mother scales decreased gradually. On the other hand IAA levels both in mother and daughter scales were increased at the start of cold treatment. Maximum IAA concentration obtained from daughter scales at the end of cold storage. At the flowering stage ABA levels were higher in mother scales than daughter scales. It seems that dormancy factor (es) might be in the mother scales. During vegetative stage ABA levels of scales were at minimum.