Abstract
Growing crops on marginal and salt-affected soils with saline water will be more important for agricultural production in the future. The most prevalent anions in saline soils, chloride (Cl-) and sulfate (SO42-) have distinct effects on plant growth, metabolism, nutrient composition, productivity, and nutrient requirements. In order to ascertain the role of phosphorus in mitigating salinity stress in tomato plants, a pot experiment was conducted in a screen house under two types of saline environments chloride-dominated (Cl-: SO42- = 7:3) and sulfate-dominated (Cl-: SO42- = 3:7), with two comparable ECe levels (non-saline and 6 dS m−1) and four graded phosphorus levels (0, 12.5, 25, 50 mg kg−1soil). The significant increase in yield up to 50 ppm added P indicated that plants require more P under chloride salinity than sulfate salinity. In non-saline, chloride, and sulfate-dominated conditions, increased P from 0 to 50 ppm increased chlorophyll 'a‘ and 'b‘ values by 21.4, 19.8 and 23.8% and 10, 20 and 14%, respectively. The reduced photochemical efficiency due to salinity, was increased 32%, 30% and 13% as P level increased from 0 to 50 ppm in non-saline, Cl--6 and SO42—6 conditions, respectively. The TSS, ascorbic acid content and titrable acidity of tomato fruits was improved with mild salinity stress but reduced with added P. The plant N, P and K content increased significantly with each added P level irrespective of types of salinity. The plant composition indicated an antagonism between phosphorus and chloride ions and synergism between phosphorus and sulfate ions.
Acknowledgments
We are thankful to CCS Haryana Agricultural University, Hisar, Haryana, for providing necessary facilities for conducting this research.
Disclosure statement
No potential conflict of interest is reported.