Effect of Exogenous Selenium Intake on Yield and Quality of Tomatoes Grown under Salt Stress

Abstract

The aim of the work undertaken is to study the impact of the exogenous supply of a biostimulant, which is selenium (sodium selenate Na2SO4), on tomatoes fruits quality under salt stress conditions. To this end, an experimental trial has been conducted on a seasonal tomato crop. Within the agricultural domain of the Regional Centre for Agricultural Research (CRRA), Sidi Bouzid, Tunisia (9 430 E, 35 010 N; altitude 354 m above sea level). The variety used is Firenze. The latter is irrigated with saline water with two different concentrations of NaCl (3 and 6 g/l of NaCl). For each type of salinity, three levels of treatment with the biostimulant were used which correspond to the control plants (without foliar spraying) and to the two doses of application of sodium selenate C1 and C2 which are respectively in the order of 0.5 mM and 1 mM Na2SeO4. The results show that salt stress has a depressive effect on the morphometric and physicochemical characteristics of fruits such as weight, size, color, Brix degree, and lycopene content. However, the application of selenium further improved these parameters. This improvement was more significant in plants that were grown at moderate salinity (3g/l) and were also sprayed with a high dose of selenium (1mM Na2SeO4). For example, yield and fruit weight increased by 228.45 percent and 73.07 percent, respectively, when compared to non-treated plants. Also, fruit width and length increased by 42.31% and 35.57%. In addition, for the physiocochemical parameters the Brix degree and the lycopene content increased respectively by 18.45% and 237.38%.