Effects of Piriformospora indica on the morphology and physiology of Poa pratensis under salt–alkali stress

In this study, we examined the alleviative effects of the fungus Piriformospora indica on the grass Poa pratensis under conditions of saline–alkali stress, in which we determined the effects on the growth, physiology, and soil indicators of P. pratensis during the later stages of growth. The results revealed that the symbiosis between P. indica and P. pratensis can effectively alleviate the damage caused by saline–alkali stress, and promote significant growth of the shoots and roots of P. pratensis under these stress conditions. Inoculation with P. indica was also found to enhance the antioxidant defense system in the leaves of P. pratensis, thereby contributing to an effective reduction in the damage caused to leaf cells by superoxide anions. Moreover, we detected reductions in the contents of H₂O₂ and malondialdehyde, as well as values of the RES index. Furthermore, this treatment was also found to promote increases in the contents of chlorophyll and osmoregulatory substances in cells, the latter of which contributed to maintaining the relative water content of cells, thereby enhancing the resistance of P. pratensis to salt–alkali stress. The detected root activity and nitrogen, phosphorus, and potassium contents in soil also indicated that P. indica has an alleviatory effect on P. pratensis plants exposed to salt–alkali stress. Our findings in this study thus indicate that P. indica can enhance the salt–alkali tolerance of P. pratensis, and that this treatment can indirectly contribute to improving saline–alkali soil.