Mitigation of salinity-induced adverse effects through exogenous application of gibberellic acid in turnip (Brassica rapa L.)

Abstract

Soil salinity is the primary factor restricting plant growth and development. In this study, the morpho-physiological, biochemical, and molecular responses of turnip seedlings to three distinct salt stress treatments were investigated: no salinity 0 mM, moderate salinity at 80 mM, and severe salinity at 160 mM. Gibberellic acid treatments were applied in three different concentrations: control, 1 mM, and 2 mM. The dry and fresh weights, shoot and root lengths, carotenoid and chlorophyll levels, K+ ion accumulation, and antioxidant enzyme activity were all decreased by salt stress, particularly at 200 mM. However, it accelerated the buildup of Na+ ions and oxidative damage. Application of gibberellic acid enhanced turnip development under salt stress. Compared with the control, the gibberellic acid-2mM recorded the highest increase in roots and shoots length (16.79–10.80%), shoots fresh and dry weights (15.21–28.39%), chlorophyll a and b (7.49–15.94%), SOD and POD (16.92–10.85%), yield weight and diameter (18.33–10.11%) during different salinity levels. This treatment also reduced the MDA and H2O2 content (15.12–10.58%), and Na+ ions in roots and leaves (20.20–5.44%). Based on these findings, gibberellic acid at a concentration of 2 mM may be a useful tool for enhancing turnip development and growth.

Keywords

• Gibberellic acid
• growth
• turnip
• salinity
• yield
• Botany