Abscisic Acid (ABA) mitigates drought stress in sunflower by enhancing water relations and osmotic adjustments

• Published in: Pure and applied biology Vol. 10; no. 1; pp. 182 - 193
• Main Author: Hussain, Safdar
• Format: Journal Article
• Language: English
• Published: Quetta International Society of Pure and Applied Biology 10.03.2021
• Subjects: Abscisic acid; Accumulation; Agricultural production; Compatibility; Drought; Environmental impact; Growth stage; Helianthus; Plant growth; Seeds; Solutes; Stress; Sunflowers; Water deficit; Water relations; Pakistan
• ISSN: 2304-2478; 2304-2478
• DOI: 10.19045/bspab.2021.100019

Drought stress significantly alters plant growth by disturbing plant water relations. Production and accumulation of compatible solutes improve plant water relations and help the plants to survive under water-limited conditions. Abscisic acid (ABA) could ameliorate the negative consequences of drought stress. Therefore, this two-year field study was conducted to infer the role ABA application (0, 5 and 10 µM) at bud initiation (BBCH-51) and flower initiation (BBCH-55) in improving plant growth under water deficiency imposed at various growth stages. Drought stress was imposed at BBCH-51 and BBCH-55 by skipping irrigation, whereas a well-watered treatment was also included for comparison. The water relations, accumulation of compatible solutes and achene yield were significantly reduced by drought stress imposed at BBCH-51 and BBCH-55. The negative impacts of drought stress were more prominent at BBCH-55 than BBCH-51. Hence, BBCH-55 proved more sensitive growth stage to drought stress than BBCH-51. The ABA application under stress-free conditions significantly reduced achene yield, with more reduction with higher ABA level. The ABA application of 5 µM either at BBCH-51 or BBCH-55 improved plant water relations, accumulation of compatible solutes and achene yield under drought stress whereas 10 µM ABA application was less effective. Therefore, it is recommended that 5 pM ABA application could ameliorate the negative impact of water deficit stress at BBCH-51 and BBCH-55 in sunflower.