IMPROVING TOLERANCE OF CORTADERIA SELLOANA PLANTS TO IRRIGATION WATER SALINITY THROUGH SALICYLIC ACID APPLICATION

In order to improve the ability of the Cortaderia selloana (pampas grass) seedlings to withstand the salinity of irrigation water, a pot experiment was conducted at the Experimental Farm of Ornamental Plants and Landscape Gardening, Res. Dept., Hort. Res. Inst., ARC, Giza, Egypt during 2017/2018 and 2018/2019 seasons. Seedlings were irrigated with a saline water containing NaCl at concentrations of 0, 6000, 8000 and 10000 ppm and sprayed with salicylic acid (SA) at concentrations of 0, 50, 100 and 150 ppm. The results showed that irrigation with saline water led to a remarkable gradual decrease in all vegetative, flowering and root characteristics as well as the contents of total carbohydrates and chlorophylls with increasing salinity levels, this was accompanied with more accumulation of proline, sodium and chlorine in leaves. Regarding foliar spraying with SA, there was an increment in vegetative, floral and root characteristics due to increasing SA concentrations until reaching the maximum growth rate at a concentration of 150 ppm, and it also increased the leaf content of total carbohydrates, total chlorophylls and proline. On the other hand, SA reduced the accumulation of sodium and chlorine in the leaves. The interaction between SA and saline water treatments cleared that SA application ameliorated the adverse effects of salinity on shoots, flowers and root growth. The best results were obtained with SA at 150 ppm for plants under a salinity of 6000 ppm, where this interaction achieved the best vegetative and floral growth equal or better than control in most cases. Accordingly, it may be recommended to spray Cortaderia selloana with a solution of SA at a rate of 150 ppm once every three weeks to obtain good growth under salinity stress of water up to 6000 ppm conditions