Effect of salt stress on the growth, Na+, Cl−, glycinebetaine and proline accumulation in sugar beet seedlings

Effect of salinity on some agro-physiological parameters in plants of one multigerm variety and five strains of sugar beet has been investigated. Plants were submitted to two salt treatments, 0 and 280mmol/L NaCl for 16 days in a water culture and the physiological responses were measured. Salinity affected all of the considered parameters. Thus, high NaCl concentrations caused a great reduction in growth parameters, such as leaf area and and dry weight of plants. But high NaCl concentrations increased the leaf thickness. These changes were associated with an increase in the Na⁺ and Cl⁻ contents in the blades, petioles and roots. The significance of inorganic ions, glycinebetaine and proline accumulation in relation to osmotic adjustment was discussed. Varietal difference were evident at high NaCl concentration for the relative reduction, salt injury index, proline and glycinebetaine content in blades except the Na⁺, and Cl⁻ content in the roots and petioles. The glycinebetaine content was higher than the proline and choline content in plant blades, and has good relationship with salinity tolerance of these sugar beet variety and strains. It seems to be that glycinebetaine had higher concentration and more contribution than proline involved in osmotic adjustment.