Salinity effects on carbohydrates, protein, and free amino acids in Miscanthus sinensis

Salinity is a major environmental stress that limits plant growth and development in arid and semi-arid regions. In order to better understand the salt-induced effects in Miscanthus sinensis, which has been identified as a good candidate for biomass production, seedlings of two accessions (salt-tolerant 'JM0119' and salt-sensitive 'JM0099') were subjected to 0 mM NaCl (control) or 250 mM NaCl (salt stress treatment) for two weeks. The contents of carbohydrates, soluble protein and total free amino acids in leaves were determined. Dramatically raised levels of soluble sugars were observed in the leaves of both accessions during salinity exposure. The starch content was slightly affected by salt stress. The total soluble protein content showed a significant reduction in leaves of JM0099 after long-time salt treatment, and the total content of free amino acids in leaves significantly increased in JM0119, while no remarkable changes were found for JM0099. Overall, accumulated soluble sugars and free amino acids provided osmotic adjustment and osmoprotection in M. sinensis leaves, and higher amount of sucrose, total free amino acids and soluble protein were associated with higher salt tolerance.