Comparison of Reversal of Abscisic Acid-Induced Inhibition of Seed Germination and Seedling Growth of Some Gramineae and Liliaceae Members by Kinetin and Gibberellic Acid

Authors: Kudret KABAR

Abstract: The degrees of reversal of the known inhibitory effect of abscisic acid (ABA) on seed germination and seedling growth by kinetin and gibberellic acid (GA3) were compared. For this purpose, the seeds of five members of Gramineae and three of Liliaceae were germinated in Petri dishes containing ABA and its combinations with kinetin and/or GA3 at 20¼C in continuous darkness for 7 days. At the end of the study, which investigated relative effectiveness in reversing the inhibitory properties of ABA on percentages of seed germination, coleoptile emergence and the time course of germination, it was determined that while GA3 alone and kinetin + GA3 for the most part had the same degree of effectiveness in Gramineae, GA3 alone was more effective in the other cases and in all cases had an effect far superior to that of kinetin alone. Kinetin was generally ineffective within these parameters. In overcoming ABA inhibition of radicle elongation, although GA3 and kinetin + GA3 were generally equally effective in barley and wheat, GA3 was superior in the other cases. Kinetin alone was largely ineffective in this parameter as well. Although the kinetin + GA3 combination was more effective than GA3 alone in overcoming ABA inhibition of coleoptile elongation in barley and wheat cultivars, GA3 alone was for the most part more effective in the other species. Kinetin alone was either successful to a lesser extent or entirely unsuccessful. In this parameter as well, GA3 had a well above that of kinetin. It is concluded from the findings that GA3 may be far more effective than kinetin in overcoming ABA inhibition of seed germination and seedling growth in Gramineae and Liliaceae.

Keywords: Germination, abcisic acid, gibberellic acid, kinetin, Gramineae, Liliaceae