Puccinellia Tenuiflora Seedlings Under Salinity Stress Ion Balance Adjustment Mechanism

As is a kind of Puccinellia, Puccinellia tenuiflora is gramineous, perennial, and herbaceous. It can live in circumstance of pH10 depending on its salt-resistant ability. To research relations of varied elements between surface and intracellular of leaves and factors effecting on these relations under stress of different concentration of Na₂CO₃, we did experiments with ESEM, EDS, TEM, ultramicrotome, and analyzed systematically from following aspects such as basic parameters of culture medium, content of element on the leaves, content of element in epidermis and mesophyll, orientation of ultrastructure of Ca²⁺-ATPase and H⁺-ATPase of Puccinellia tenuiflora. We came to the conclusion that relative content of Na of leaves surface under stress of Na₂CO₃ was higher than that in natural circumstance, while relative content of K of leaves surface under stress of Na₂CO₃ was lower than that in natural circumstance. And we also found that under stress of concentration of 0⁴0mmol/L of Na₂CO₃, ratio of Na/K increased but when the concentration was 40mmol/L up, the ratio changed hardly, which might be resulted from the ability of lightening poison of Na by discharging it under lower concentration of Na₂CO₃ and absorbing K under higher concentration. We studied relations of relative content of Na and K in cell wall, vacuole, and cytoplasm both in epidermis and mesophyll, and got results as following: Under concentration of Na₂CO₃ in my experiment, as relative content of Na is concerned, it was higher in cell wall and vacuole than in cytoplasm both of epidermis and mesophyll, however, when it comes to K, it was lower in cell wall of epidermis than all the others. We calculated ratio of Na/K based on results above and found the ratio in cytoplasm was less than that in cell wall and vacuole both in epidermis and mesophyll, which showed us seedlings of Puccinellia tenuiflora did contain low Na/K to lighten poison of high concentration of Na. Under concentration of Na₂CO₃ in my experiment, relative content of Ca in cell wall and vacuole was higher than that in cytoplasm both of epidermis and mesophyll, which can be the base to confer ratio of Na/Ca in vacuole was not as high as that in cell wall and cytoplasm and thereby contracture and function of membrane were protected. Activity of Ca²⁺-ATPase in mesophyll and thin wall cell was enhanced when Puccinellia tenuiflora seedlings were under stress of lower concentration of Na₂CO₃ yet lightened under higher stress. Activity of H⁺-ATPase in mesophyll changed hardly when seedlings were under stress of lower concentration of Na₂CO₃. As concentration was increased, the activity was enhanced, but further increase of stress could decrease the activity of H⁺-ATPase.