Effect of Salinity Stress on Dry Matter Accumulation and Ion Distribution Pattern in Five Safflower (Carthamus tinctorius L.) Genotypes

A hydroponic experiment was conducted to evaluate the effects of salt stress on safflower genotypes under greenhouse conditions. The experiment was arranged as a factorial one based upon a completely randomized design with three replications. Five safflower genotypes (Arak2811, Nebraska10, SOD25, CA116, and CA128), and four salinity treatments (0, 0.3, 0.5, and 0.7 percent of NaCl) were employed as experimental factors. Salinity exerted considerable effect on the growth parameters. Plant height, shoot and root dry weight, the concentrations of Na, K, Ca, and Mg in leaves and roots, and also the concentration of proline in leaves were meseared in samples obtained from the plants harvested one month after being exposed to salinity. Salinity decreased plant height, shoot and root dry weight, as well as the concentration of K, Ca, and Mg in leaves and roots. Howevere, the concentration of Na in shoots and roots increased under saline conditions. There was a significant interaction between the levels of salinity and genotypes for shoot dry weight. Among tested genotypes CA128 showed to be more salt tolerant in terms of dry matter accumulation regarding all levels of salinity. The effect of salinity on shoot/ root ratio was not significant. The concentration of proline in the leaves increased in saline treatments but the differences between genotypes and the interactions between the levels of salinity and genotypes were not significant as far as the concentration of proline in the leaves is concerned. The ratio of Na/K in the leaves and roots was higher in the plants subjected to salt stress. The differences between genotypes were significant regarding this ratio. Among the tested genotypes the ratio of Na/ K in the leaves was highest for Nebraska10. Howevere, the interaction between the levels of salinity and genotypes was significant for the ratio of Na/ K in plant tissues. The results of this experiment showed that salinity can significantly affect the growth of safflower and the responses of safflower genotypes to salinity might be different in terms of dry matter accumulation and in terms of ionic relations.