Effect of NaCl-induced Salt Stress at Germination and Early Seedling Growth Stage in Lupinus albus L.

Salinity is a primary abiotic factor affecting agricultural productivity in arid and semiarid environments. The stages that are most vulnerable to salinity are germination and early seedling growth. There are limited reports on the responses of Lupinus albus L. to salinity. Therefore, in the study, we aim to test germination and early seedling growth of L. albus under different salinity levels. To this end, seeds of L. albus were treated with different concentrations (0, 50, 100, 150, and 200 mM) of NaCl under laboratory conditions. A total of 16 parameters, including germination and growth, were examined. The results showed that under 200 mM NaCl, germination percentage (GP) decreased by 13.4% and germination rate index (GRI) decreased by 69.24%, while mean germination time (MGT) increased by 30.02%. In addition, the shoot length (SL), root length (RL), shoot fresh weight (SFW), root fresh weight (RWF), and root dry weight (RDW), root to shoot dry matter (R/S DM), shoot water content (SWC), root water content (RWC), and seedling vigor index (SVI) were reduced respectively by 82.69%, 75.65%, 53.30%, 70%, 66.66%, 70.86%, 23.47%, 0.35% and 82.57% under 200 mM NaCl, compared to the control condition. However, root to shoot ratio (R/S), shoot dry weight (SDW), shoot dry matter (SDM), root dry matter (RDM) were increased by 43.33%, 65.07%, 249.68%, and 3.22% under 200 mM NaCl. Overall, the study results showed that the critical level to mitigate the negative effect of salinity is 150 mM NaCl (-0.6 MPa osmotic potential) for germination and 50 mM NaCl (-0.2 MPa osmotic potential) for growth. Therefore, L. albus has a low tolerance to salinity.