Water relations in rice seedlings in saline medium

Abstract

We evaluated the seedling water content (SWC), leaf relative water content (LRWC), transpiration intensity (TI), and the cell sap concentration (CSC) in four rice varieties, differentiated by the degree of their salt tolerance. Pokkali and IR24 were tested for salt tolerance and MI 48 and Perla for susceptible behavior. Seedlings of four varieties were sown in nutrient solution under controlled laboratory conditions using Hoagland nutrient solution (control) and Hoagland nutrient solution enriched with NaCl (0.7%,). The pH was kept at 5.0. The SWC, LRWC, and TI were determined by gravimetric methods and the CSC by refractometry in five replications at 21 d after planting. The SWC, LRWC, and TI significantly diminished under salinity stress in all varieties (see table) because plants could not absorb adequate water. The TI was more pronounced than SWC or LRWC. Plants adjust their T1 as a defense mechanism to compensate for water loss.