Effects of Gibberellic Acid Treatment for Pollen Sterility Induction on the Physiological Activity and Endogenous Hormone Levels of the Seed in Safflower

Authors: HASAN BAYDAR

Abstract: In this research, our aim was to determine the effects of gibberellic acid, which was applied to safflower plants (Carthamus tinctorius L. cv. Dinçer 5-118) for pollen sterility induction, on some physiological activity and endogenous hormone levels of the seeds. Exogenously applied gibberellic acid (GA_3) strongly influenced the endogenous hormone levels of the seeds by decreasing the levels of GA_3 and zeatin, and increasing the levels of indole-3-acetic acid (IAA) and abscisic acid (ABA). The lowered endogenous GA_3/ABA and zeatin/IAA ratios in the seeds significantly decreased the germination percentage and hypocotyl elongation, respectively. The seeds from GA_3 treated plants had more hull percentage and less oil content than seeds from the non-GA_3 treated plants. As a consequentce, it was indicated that poor germination and emergence vigor might be a major problem in hybrid safflower seeds produced from plants treated with gibberellic acid.

Keywords: Safflower, Carthamus tinctorius L., Seed physiology, Gibberellic acid, Plant hormones, Pollen sterility

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