Tomato plant nutrition as affected by arsenite concentration

Abstract

As a part of a general study of environmental contamination by arsenic (As), the effects caused by arsenite on the processes of uptake and accumulation of macronutrient elements calcium (Ca), potassium (K), magnesium (Mg), nitrogen (N), and phosphorus (P) in tomato plants (Lycopersicum esculentum Mill, cultivar Marmande) were studied. Tomato plants were grown in nutrient solution (hydroponic growing system) containing three levels of As (added as sodium arsenite, NaAsO₂): 2, 5, and 10 mg As L^‐1. One control, with no As addition, was also included. Vegetative growth and fruit yield were affected by As level in the nutrient solution. Plant growth, expressed as dry and fresh weights of leaves and roots, were significantly restricted by As. Fresh fruit production decreased to 60.7, 47.3, and 23.3% at 2, 5, and 10 mg As L^‐1, respectively, compared to control. Contamination by As caused changes in both concentration and uptake of all the macronutrients studied. A reduction in the root concentration of P, Ca, and Na was observed while there was a statistically significant increase in root N and K. Arsenic treatments changed the foliar concentrations of P, K, and Ca from sufficiency to deficiency levels. These biologically significant reductions in leaf P, K, and Ca, however, were not important enough to justify the toxic effects of arsenite on tomato plants as a simple nutritional disorder.

Notes

Corresponding author. Present address: Wetland Biogeochemistry Institute, Louisiana State University, Baton Rouge, LA 70803–7511; Fax # [phone]; e‐mail address: [email protected].