MITIGATION OF SALT-INDUCED DAMAGES IN WHEAT BY EXOGENOUS APPLICATION WITH ASCORBIC ACID, SILICON AND GIBBERELLIN

Abstract

Considering the salinity issue three studies were conducted to find out the effect of salt stress on morph-physiological and biochemical changes of wheat (BARI Gom26)

as well as mitigation of the adverse effect through exogenous application of Ascorbic Acid (AsA), Silicon (Si) and Gibberellic Acid (GA3). The performances of secondary seeds were also evaluated. The studies were conducted at the net house and plant physiology laboratory of Agronomy department, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh. In field experiment, four levels of salt stress (0, 50, 80, 120 mM NaCl) were applied on growing media of wheat seedling at 20 days after sowing and grown up to harvest where in laboratory experiment salinity were applied 3 days after sowing grown upto 10 days. In both experiments AsA (2 mM ascorbic acid), Si (200 µM SiO 2 ), GA3 (100 µM gibberallic acid) were applied as foliar spraying (several times with interval) in another set of respective salt stress treatments. In field study salt stress decreased plant growth, biomass, water status and yield attributes by altering ionic balance, hampering osmotic status and reducing chlorophyll (chl) content. In the laboratory experiment, salt stress increased reactive oxygen species (ROS) generation and lipid peroxidation which contributes to alteration of osmotic status and chl content as well as growth and biomass of the plant. However, foliar application of AsA, Si and GA3 on salt affected plant decreased ROS generation, lipid peroxidation and proline production; increased water status and chlorophyll pigments which contribute in improved growth and yield of wheat seedling in contrast to respective stress. Moreover, the findings of the third experiment confirmed that AsA, Si and GA3 enhanced the performance of secondary seeds originated from the first experiment. Considering the results of all experiments GA3 performed better than the AsA and Si in mitigating salt stress.