Effects of gibberellin A4/7/9 application and the levels of endogeneous plant hormones on flowering in the red pine (Pinus brutia ten.) seed orchard

The aim of this study is to determine the effects of exogenously applied gibberellin A4/7/9 (GA4/7/9 ) mix and the level of endogenous plant hormones, gibberellin A3 (GA3) and abscisic acid (ABA), on the numbers of flowers produced on the ramets of a clone in Turkish red pine {Pinus brutia Ten.) seed orchard. The trees used in this study have a clone number 9273, are located in 1 1 years old Turkish red pine seed orchard in Çığlık district, Antalya and are originated from Gündoğmuş-Eskibağ. Two types of treatments have been applied on the trees: ethanol and GA4/7/9. Endogenous free-, bound-, total-GA3 and endogenous free-, bound-, total -ABA quantities have been determined in the tissue sampled taken from the vegetative shoot apex of treated and untreated (control) trees. Tissue samples are exposed to processes of extraction and purification to analyze endogenous GA3 and ABA. The high performance liquid chromatography (HPLC) instrument has been used to determine the quantities of GA3 and ABA. At the end of the study, it was found that both free- and bound- endogenous GA3 and endogenous ABA were present in the tissues; and there were no correlation between the level of these hormones and the numbers of female and male flower production. However, it was found that GA4/7/9 application statistically promotes female and male flower production; and it was more effective on male flowering than female flowering. KEY WORDS: Pinus brutia Ten., Gibberellin, Gibberellin A4/7/9, Abscisic Acid, Flowering, Flower Production, High Performance Liquid Chromatography COMMITTEE: Prof. Dr. Ş. Fatih TOPCUO?LU (Adviser) Prof. Dr. Kani IŞIK Prof. Dr. Şadiye GÖZLEKÇÎ 11