Variations in water relations, stomatal characteristics, and plant growth between quinoa and pea under salt-stress conditions

摘要

Salinity is a primary restrictive factor for crop growth at both the cellular and whole plant levels. The effects of salinity on water relations, stomatal morphology and physiology, and seedling growth in quinoa and pea were investigated to compare the salt tolerance mechanisms of these two species. The seedlings of quinoa and pea were cultivated in Hoagland’s solutions supplemented with different NaCl concentrations (0, 100 and 200 mM). For quinoa,the relative water content, transpiration ratio, osmotic potential, stomatal conductance, stomatal density, and stomatal length were all reduced significantly by salt stress. Interestingly, a greater stomatal conductance of the abaxial surface in quinoa was found during salt stress in comparison with the control. Similar trends (root stem leaf) were found for leaf water potential in quinoa and pea. For different organs, quinoa possessed greater leaf water and osmotic potentialsthan pea, indicating that quinoa might limit the translocation of inorganic ions to maintain the water balance. The turgor pressure in the two species increased significantly, which could play an important role in sustaining seedling growth. In conclusion, quinoa was less affected by salinity, which was verified by the different physiological responses of stomatal and plant water states.