Role of Abscissic Acid (ABA) Biosynthesis and Superoxide Ions Produced during Germination and Growth of Wheat Seedlings

Effect of sodium tungstate, ST (an inhibitor of ABA biosynthesis) and tiron, T (specific scavenger of superoxide ions) was studied on seed germination, growth and antioxidant potential of shoots and roots of wheat seedlings of two cultivars C306 (ABA-higher sensitive) and PBW343 (ABA-lesser sensitive) to study the role of ABA biosynthesized and superoxide ions produced under normal (non-stressed) conditions for these processes. Seed germination was decreased under both ST and T supply in both cultivars. Such decrease was not so higher under ST in both cultivars and under T in PBW343 but was much higher under T in C306. Length (shoot and root) of the plant was increased but fresh biomasses of shoots and roots were not affected under ST in both cultivars. Under T, both length and biomasses were increased in both cultivars. Antioxidant potential was decreased in the form of decreases in antioxidant enzymes, ascorbate contents, ascorbate to dehydroascorbate ratios; increases in malondialdehyde contents, H₂O₂ contents under ST and under T in both cultivars. Proline contents were increased under ST and under T in both cultivars but increases were higher in C306 than in PBW343.