Potassium silicate has a better mitigating effect than Potassium Nitrate on Salt Stress of Kentucky Bluegrass (Poa pratensis)

Potassium silicate has a better mitigating effect than Potassium Nitrate on Salt Stress of Kentucky Bluegrass (Poa pratensis

Potassium or silicon could enhance salt tolerance of plants. However there is little information about the combined effects of these two elements on plants under stress. Effects of KNO3, K2SiO3 with K+ removal or K2SiO3 on NaCl tolerance of Poa pratensis were compared. Leaf gas exchange, osmotic adjustment substances, antioxidative enzyme activities and biomass were compared between different treatments. It showed that the addition of KNO3 or K2SiO3 could alleviate salt stress by promoting growth; reducing intracellular proline, soluble protein and soluble sugar; increasing chlorophyll content, photosynthetic rate, water use efficiency and antioxidative enzyme activities. K2SiO3 had a better mitigation than KNO3 when the K+ concentration was the same. At the same Si concentration, the mitigating effect of K2SiO3 was not significantly different from that of K2SiO3 with removal of K+. The results indicated that there was no synergistic effect between Si and K.