FOLIAR SPRAY OF MINERAL ELEMENTS ANTAGONISTIC TO SODIUM ― A TECHNIQUE TO INDUCE SALT TOLERANCE IN PLANTS GROWING UNDER SALINE CONDITIONS

Plants growing in saline substrates show deficiencies in absorption of some essential mineral elements through roots due to presence of excessive sodium in the rhizosphere. Sodium being antagonistic to other cations does not let them enter in roots and hence apart from its own toxicity in metabolism, the plants suffer with deficiencies of some mineral elements necessary for growth. Potassium an essential mineral element is much affected due to this antagonistic behavior of sodium ion. Lagenaria siceraria being a broad leaf vegetable was selected for these experiments. Plants growing at saline substrate was sprayed with specially prepared spray material containing different dilutions of potassium nitrate. The anatomy of leaf with special reference to that of stomata was also studied to ensure absorption of required minerals. Plants were grown in Lysimeters filled with sandy loam and irrigated with 0.2 % (EC iw 3.4 dSm-1) and 0.4 % (EC iw 6.1 dSm-1) dilutions of sea salt. They were further subjected to four treatments viz., i) non- spray, ii) foliar spray with water, iii) foliar spray with 250 ppm KNO3, iv) foliar spray with 500 ppm KNO3 respectively. Those sprayed by 250 ppm KNO3 under saline conditions not only inhibited toxic effects of salt on fruit formation, but also increased their production 76.91 % by weight per plant, Spray with higher concentrations of KNO3 did not show much benefit