Assessment of laser beam effect on traits associated with salinity tolerance at seedling stage of rice (Oryza sativa L.)

Salinity stress can severely affect rice plants at seedling stage. In order to study the laser irradiations effect on characteristics associated with the salt tolerance of rice at seedling stage، a nutrient solution experiment was conducted as a factorial arrangement based on completely randomized design with three factors including four salinity levels (0، 30، 60، and 90 mM sodium chloride)، two laser levels (Irradiated and non-irradiated seeds as the control) and two cultivar levels (susceptible- IR29 and tolerant- FL478) with three replications in the greenhouse of Tehran University. Results indicated that using laser treatment in both cultivars significantly increased plant height، shoot dry weight، leaf relative water content، root length، root volume، root dry weight، while significantly decreased SPAD value and cell membrane electrolyte leakage percentage. Moreover، in laser- irradiated treatments shoot dry weight enhancement and SPAD values reduction، were higher in cultivar IR29 comparing to cultivar FL478 at all salinity levels. While FL478 showed greater relative water content، this could be possibly due to the greater stability of the membrane in holding water. According to the results of these experiments، it appears that laser rays induce bio-stimulations in plants which can be effective in salinity tolerance.