Physiological and Biochemical Characteristics of Salt Stress Tolerance in Selected Varieties of Sunflower Under Various Treatments of Potassium, Zinc and Gibberellic Acid

摘要

The effects ofpotassium, zinc and gibberellic acid foliar spray on salt stresstolerance, free proline, total phenolics, carbohydrates and chlorophyllcontents in sunflower varieties were evaluated. Eight varieties ofsunflower were grown in glass house and NaCl (150 mM) was added toroots alone and in combinations with KNOsub3/sub, ZnSOsub4/suband GA3 foliar spray. Different varieties were evaluated for salttolerance through leaf disc assay (LDA). Various test solutions of NaClwere used to induce salt stress. T1 treatment (150 mM NaCl only)significantly decreased the greenness % in all of eight varieties ofsunflower as compared to control C. The T2 treatment (150 mM NaCl +Potassium) enhanced the greenness % and maximum greenness % wasobserved in the SMH-0917 (76.00 %) followed by Ausigold-7 (75.50 %).The treatment T3 (150 mM NaCl + Zinc) and T4 treatment (150 mM NaCl +100 ppm of GA3) retained the greenness % in leaf discs compared tocontrol. The free proline and total phenolic contentssignificantly increased in all of eight varieties of sunflower whentreated with K, Zn, GA3 and NaCl. Positively significant correlationwas found between greenness % with proline (Rsup2/sup = 0.86) andtotal phenolics contents (Rsup2/sup = 0.83). Conclusively; salttolerance could be increased by the application of K, Zn and GAsub3/sub.