Responses of antioxidant defense system of Helianthus annuus to abscisic acid treatment under drought and waterlogging.

Yüksel Keleş, Serpil Ünyayar

The effect of abscisic acid (ABA) treatment on growth pigments and antioxidant defense system were in vestigated in seedlings of Helianthus annuus (cvs. Nantio F1 and Özde mirbey) subjected to drought and waterlogging stress. In addition, seedlings were sprayed with 10 µM ABA three times every other day. Reltive growth rate (RGR) was significantly reduced in both genotypes under drought stress, however, this growth inhibition was less in ABA-treated plants. Total chlorophyll content increased by drought stress in both gentypes. Ascorbate was not influenced by drought, while α-tocopherol in creased in cv. Nantio F1. Ascorbate and α-tocopherol in creased with drought stress in cv. Özdemirbey. ABA treat ment de creased ascorbate and ß-carotene contents while it increased α-tocopherol and xan...