Gamma radiation and hormone treatment as tools to reduce salt stress in rice (Oryza sativa L.)

We investigated the effects of jasmonic acid (JA) and gamma irradiation on the growth and metabolic responses to salt stress in rice (Oryza sativa L.) plants. The relative growth rate (RGR), relative water content (RWC), and chlorophyll (Chl) content were lower in NaCl-treated plants than in the control, whereas the malondialdehyde content (MDA), electrolyte leakage (EL), and contents of proline and abscisic acid (ABA) were higher in the treated plants. When induced by the salt stress, those effects, however, were somewhat alleviated by the application of JA or gamma irradiation. The most significant response was manifested by the proline content, with relatively lower values for alleviation being recorded for the contents of RGR, RWC, Chl, and MDA, as well as EL. Moreover, although total Chl content was not significantly influenced by JA or gamma irradiation in plants under salt stress, an increase in the level of Chl a resulted in a markedly changed ratio of Chl a/b. The degree of alleviation, in terms of growth and metabolic responses, was more extensive for JA-treated plants than for those exposed to gamma irradiation.