The effect of some in/organic osmolytes in salt tolerance of Aeluropus lagopoides plants

Aeluropus lagopoides is a Graminaceae related halophytic plant belongs to Poaceae family that grows in salty soils. In this research، several indicators were studied on plants under different concentrations of NaCl in hydroponic culture. Comparison the fresh and dry weights of roots، shoots، and whole plants under various treatments determined that the highest growth rates occur in the presence of 300 mM NaCl، however، lower and higher salinity reduces the growth rate. While the root length was highly depended on the salt concentration، shoots height did not vary significantly. Variances analysis showed that cations (Na+ and K+) are distributed differentially in the roots and shoots when the control and salt-treated plants were compared، and as a result، salinity had significant effect on roots and shoots Na+ content. In general، it may be stated that Aeluropus lagopoides reacts differently to various concentrations of Na+. Apparently، at low environmental NaCl concentrations the root system is developed and the absorbtion of cations is increased to provide water and essential minerals. In other words، it uses mineral osmolytes that are not toxic for the cell at low exogenous NaCl concentrations in order to maintain intracellular water and osmotic pressure، whereas at medium and high concentrations of NaCl، organic osmolytes like glycine betaine and proline are accumulated، respectively، to regulate osmotic pressure. As a result، the rate of plant growth is reduced in order to stand high salinity for a while. Furthermore، it seems that because of the strongly regulation of Na+ and K+ transport from root to shoot their contents are regulated tightly in shoots.