Enhancing wheat resistance to salinity: The role of gibberellic acid and β-carotene in morphological, yielding and ionic adaptations

Abstract

Salinity is highly toxic to wheat growth. Both β-carotene and gibberellic acid can mitigate the saline toxicity in wheat, independently and in combined form, by positively impacting growth and yield under saline conditions. To explore our hypothesis two wheat varieties (Faisalabad-2008 and Galaxy-2013) were grown in the sand medium under two levels of salinity (0 mM and 150 mM) nourished with Hoagland’s solution and sprayed with four different foliar approaches (water spray = T0, 0.75 mM GA3 = T1, 0.25 mM β-carotene = T2, 0.75 mM GA3 + 0.25 mM β-carotene = T3). Salinity comprehensively decreased the growth metrics of wheat. While foliar applications of 0.75 mM GA3 0.25 mM β-carotene significantly mitigate this toxicity by physiological alterations. Shoot fresh weight (p < 0.001) (maximum at T3, root fresh weight (p < 0.05) maximum at T2, Shoot dry weight (p < 0.01) maximum at T3) reflect significant mitigation under salinity while root dry weight, shoot length, and root length non-significant response. Leaf calcium (p < 0.01) and root sodium (p < 0.001) readings showed much positive response at T3. Flavonoids (p < 0.05) maximum at T3, free proline (p < 0.01) maximum at T3, ascorbic acid (p < 0.05) maximum at T3, and seeds weight (p < 0.001) Maximum at T1. Overall Faisalabad-2008 performed better in saline conditions when treated with foliar application of GA3 and β-carotene (water spray = T0, 0.75 mM GA3 = T1, 0.25 mM β-carotene = T2, 0.75 mM GA3 + 0.25 mM β-carotene = T3). This study is recommended for the growth of wheat cultivars by foliar applications of GA3 and β-carotene under salt stress.