Exogenous application of auxin to ameliorate adverse saline and drought conditions in wheat.

Abstract

Adverse environmental conditions such as drought and saline conditions are the principal factors that restrict plants growth and production. Plant growth regulators play key role to alleviate the abiotic stress in plants.Present study was aimed to investigate the physiological response of four wheat cultivar (Aari, Baras, Sahar and Aas) under saline and moisture deficit and the role of exogenous application of IAA to ameliorate adverse conditions in these varieties. The response of four varieties under saline and drought stress and exogenous application of indole-3-acetic acid (IAA) was studied in pot experiment. Experiment was conducted in growth chamber in Quaid-i-Azam University Islamabad. For saline stress, NaCl solution (100mM) was prepared and applied at the time of sowing while drought stress was applied after two weeks by withholding water. Foliar application of IAA (80 ppm solution) was prepared and applied after three weeks.After four weeks plants were uprooted and preserved at -20°C. Variation in relative water contents along with sugar contents, protein contents, proline contents and anti-oxidants enzyme activities were measured. Decrease in relative water contents were associated with increase in sugar contents, protein contents, proline contents and anti-oxidants enzyme activities, observed under saline and drought conditions. On the basis of these parameters, Sahar is the most tolerant to drought followed by Baras, Aari and Aas. Similarly under saline stress,Sahar is the most tolerant followed by Aas, Aari and Baras. Adverse effect of drought and salt were ameliorated by the foliar application of IAA in four studied varieties and tolerance in each variety increased significantly. Response of each variety to IAA remained similar. Key Words: Sahar, Aas, Aari, Baras, Indole-3-acetic acid, drought stress, salt stress. Abstract Adverse environmental conditions such as drought and saline conditions are the principal factors that restrict plants growth and production. Plant growth regulators play key role to alleviate the abiotic stress in plants.Present study was aimed to investigate the physiological response of four wheat cultivar (Aari, Baras, Sahar and Aas) under saline and moisture deficit and the role of exogenous application of IAA to ameliorate adverse conditions in these varieties. The response of four varieties under saline and drought stress and exogenous application of indole-3-acetic acid (IAA) was studied in pot experiment. Experiment was conducted in growth chamber in Quaid-i-Azam University Islamabad. For saline stress, NaCl solution (100mM) was prepared and applied at the time of sowing while drought stress was applied after two weeks by withholding water. Foliar application of IAA (80 ppm solution) was prepared and applied after three weeks.After four weeks plants were uprooted and preserved at -20°C. Variation in relative water contents along with sugar contents, protein contents, proline contents and anti-oxidants enzyme activities were measured. Decrease in relative water contents were associated with increase in sugar contents, protein contents, proline contents and anti-oxidants enzyme activities, observed under saline and drought conditions. On the basis of these parameters, Sahar is the most tolerant to drought followed by Baras, Aari and Aas. Similarly under saline stress,Sahar is the most tolerant followed by Aas, Aari and Baras. Adverse effect of drought and salt were ameliorated by the foliar application of IAA in four studied varieties and tolerance in each variety increased significantly. Response of each variety to IAA remained similar. Key Words: Sahar, Aas, Aari, Baras, Indole-3-acetic acid,