Contribution of QuitoMax® to the hormonal and enzymatic metabolism in tomato under saline stress

Abstract

ABSTRACT Salinity stress severely restricts plant nutrition and hinders biochemical and physiological processes crucial for growth. In several crop systems bioactive products which confer growth promotion, are applied as a sustainable alternative for contributing to food security. The aim of this work was to evaluate the biochemical contribution of QuitoMax® to hormonal and enzymatic metabolism in tomato under saline stress. Three treatments were applied: saline without QuitoMax®, nonsaline + QuitoMax® and saline + QuitoMax®. A tolerant (Amalia) and a susceptible (Claudia) tomato variety were used as experimental models. The normalized difference vegetation index (NDVI) was measured as a morphological variable, and peroxidase (POD), glutamine synthetase (GS) and nitrate reductase (NR) enzyme activities were determined. Gibberellic (GA) and abscisic acid (ABA) concentrations were also determined. Due to the effects of QuitoMax®, the plants maintained high NDVI values even under saline conditions. A decrease in POD and GS activity and an increase in NR activity were also found. The GA concentration in the leaves was higher in the tolerant variety when QuitoMax® was applied than in the saline treatment but lower in the susceptible variety. The opposite behavior was found when the ABA concentration was quantified. This study demonstrates the protective action of QuitoMax® under salinity stress on tomato crops in both tolerant and susceptible varieties. In crux, QuitoMax® can be opted as a shotgun approach to tackle salinity in tomato.

Keywords

• Peroxidase activity
• glutamino synthetase
• nitrato reductase
• ABA
• GA