Simultaneous Treatment of Different Gibberellic Acid Doses InducesIon Accumulation and Response Mechanisms to Salt Damage in MaizeRoots

Abstract

The present study was aimed to find out the changes in plant responses to salinity with GA3 treatments. With this aim, combinations effects of salinity (350 mM NaCl) and three different doses of gibberellic acid (100, 300 and 500 ppm) on physiological and biochemical analysis of maize (Zea mays L.) roots were studied in soil experiment. The obtained results showed that treatment of GA3 (300-500 ppm) caused a reduction in salt-induced damage, improvement in biomass yield, regulation in water status, increasing proline level, reactive oxygen species (ROS) scavenging capacity, induction of SOD (36.6% at 500 ppm), CAT (28.5% at 500 ppm), APX (3.18 and 3.26 fold at 100 ppm and 500 ppm), GST (2.83 and 2.59 at 100 ppm and 500 ppm) enzyme activities, while POX activity was decreased only at GA3 (31.3% at 500 ppm), and thus alleviation of the oxidative damage. The results indicated that the salt application had a negative effect on the macro and micronutrient concentrations in roots. Otherwise, N, Ca and P concentration was increased by gibberellic acid under salinity, while, K, Cu, Mn, Fe and Zn were reduced compared to salt treatment alone. To sum up, these results showed that GA3 could be used as a signal molecule in antioxidant enzyme regulation related with ions for increasing salt tolerance in maize under salinity.