Effect of soil salinity on the growth, amino acids and ion contents of rice transgenic lines
Rice seedling of different transgenic lines (T-99, T-112, T-115 and T-121) were grown in sand culture with salt concentration of 0, 50, 100 and 150 mM to determine the effect of salinity on growth, amino acid, and ion contents. It was observed that all the lines could tolerate concentration of up to 50 mM of salt solution. The lines (T-99, T-112 and T-115) were more salt tolerant even at a concentration of 100 mM of NaCl with their relative growth rate (RGR), and net assimilation rate (NAR) were unaffected as compared to the control. With the increase in salt concentrations, the proline contents increased for all the transgenic lines. On the other hand, a gradual decrease in the contents of glycine and arginine were observed with the increase in salinity treatments. A massive increase in the Na+ contents was measured in all the transgenic lines by application of the saline solutions. The K+ and Ca++ contents decreased with the increase in salt concentrations. The present study shows that although the plants accumulated Na, the lines T-99, T-112 and T-115 could tolerate concentrations of up to 100 mM.
Key words: Salt stress, proline, glycine, Na, K, Ca, Oryza sativa.