The physiological mechanisms underlying how eremophyte Reaumuria soongorica responses to severe NaCl stress

In this study, we investigated the effects of 150 mmolL-1 NaCl on the growth, salt secretion, and the Na+ distribution pattern of Reaumuria soongorica. The results showed that 150 mmolL-1 NaCl has a positive effect on the growth of R. soongorica, the fresh weight and dry weight indicated significant enhancement by 14% and 18%, respectively. However, any significant changes of the tissue water content were not observed in R. soongorica treated with 150 mmolL-1 NaCl for 7 days. When exposed to high concentration NaCl condition, the net Na+ uptake rate in root significantly increased for 44 times as that of control; correspondingly, the Na+ secretion and accumulation in shoots of R. soongorica exhibited significant enhancement which was 25 times and 2.1 time than that of control, respectively. Further analysis showed that the percentage of Na+ secretion increased from 4.3% in the control to 35%, and the percentage of Na+ accumulation in shoots also was 43%. These findings suggest that, under saline environment, R. soongorica is able to absorb large quantity Na+, most of which where Na+ were secreted through salt gland or accumulated in shoots, thus to alleviate the toxic effects of Na+ and maintain water status in plant, which contribute to stimulate the growth of plant.