Biomass production and protein synthesis by alfalfa under salt stress

Abstract

This study was conducted on alfalfa (Medicago sativa L.) plants under normal and salt stress conditions using Hoagland solution in a growth chamber. The biomass production and protein synthesis by one low salt tolerant alfalfa cultivar ('Mesa‐sirsa 83CL, MS 83CL') and one germination salt tolerant selection ('Mesa‐sirsa cycle 3, MS Cycle 3') were investigated under normal (Control = 0.3 bars osmotic pressure) and NaCl salinity (6.0 bars osmotic pressure) conditions. The 15‐day‐old seedlings were grown for 15 additional days in complete Hoagland solution before and 90 days after the completion of salt treatment. Three harvests were made on days 30, 60, and 90 after the completion of salt treatment.

Total biomass production (fresh and dry weights of shoots) by plants were measured and plant tissues were analyzed for crude protein and protein‐N content. The MS Cycle 3 selection produced slightly more (statistically not significant) biomass than the standard cultivar under salt stress condition. However, this difference was statistically significant when compared the alfalfa cultivar and the selection under normal (non‐saline) condition. Total crude protein and protein‐N content of plants were substantially higher for MS Cycle 3 selection compared with the MS 83CL cultivar for any corresponding treatment. The NaCl stress resulted in substantial reduction in all these parameters for both the alfalfa cultivar and the selections.