Salinity-phosphorus interaction in forage sorghum plants

Abstract

It was conducted an entirely randomized experiment using 3x2 factorial arrangement with four replications A treatment was used as control (without addition of NaCl) and another as saline (containing 72 mM of NaCl). Both control and salt-stressed seedlings were subjected to three phosphorus concentrations in the nutrient solution: 0.025, 0.250 and 0.500 mM. After 15 days of salt treatment, plants were harvested and leaf area and shoot and root dry mass were measured. The mature leaves were harvested, frozen dried, grounded and used to measure P contents. Leaf P contents were higher in salt-stressed than in control plants for both genotypes. The growth responses to P application in the nutrient solution were different in control and salt-stressed plants. Shoot dry mass of control plants of this genotype raised 34, 0% when the P concentration in nutrient solution was increased from 0,025 to 0,500 mM. On the other hand, it was observed a decrease of 5% in shoot dry mass of salt-stressed plants for the same increase in P concentration. The results showed a significant salinity x phosphorus interaction in sorghum plants for all evaluated parameters.