A research on the abscisic acid contents of sunflower (Helianthus annuus L.) seedlings and discs that the effect of mercury (Hg++)

ABSTRACT Sc. THESIS A RESEARCH ON THE ABSCİSİC ACİD CONTENTS OF $XJmLOWER(Hetiant!ut$ annum L.) SEEDLINGS AND LEAF DISCS THAT THE EFFECT OF MERCURY(Hg++) Alpaslan KOÇAK Fırat University Graduate School of Natural and Applied Sciences Department of Biology 2004, Page: 28 In this study, the effects of mercury (HgCI2) on abscisic acid contents of sunflower seedlings and leaf discs were investigated. Also one-week-old sunflower seedlings were used. Seedlings were left in the mercury chloride at 0.03, 0.05 and 0.07 mM concentration prepared with hoagland solution ten day growing. Abscisic acid contents one by one tissues root, shoot, leaf of seedlings were determined by HPLC. Leaf discs were taken from leaves of seedlings with hoagland solution one month growing. According the results we have obtained, mercury stress caused increased at significant rations, in the abscisic acid contents of root, shoot, leaf, seedling and leaf discs. The abscisic acid contents of root, shoot, leaf, seedling and leaf discs the sunflower to which mercury salt treatment were increased by 141- 206%, 131-269%, 223-300%, 202-287% and 277-367 % (p<0.01), respectively, compared to the control seedlings. It was determined this increases effect to mercury salt concentration. The abscisic acid contents of root, shoot, leaf the seedlings treated 0.05 and 0.07 mM mercury salts were found higher than that of seedlings treated with 0.03 mM mercury salt. Although the abscisic acid contents of the seedlings treated 0.05 and 0.07 mM mercury salts were shown at different, this values of view no significant (p<0.05) statistically meaningful. The abscisic acid contents which increase root, shoot, leaf and leaf disc were determined to be as leaf disc, leaf, shoot and root, respectively. Key Words: Sunflower seedling, leaf disc, mercury stress, abscisic acid V