The influence of silica upon quantitative, qualitative, and biochemical traits of tomato under water stress

Water stress is by far the most serious limiting factor to tomato (Solanum lycopersicom) production, partic-ularly in Iran where located in arid and semi-arid regions. Silicon (Si) is considered an effective element to mitigate the adverse effects of water stress by promoting plant growth and production. Therefore, the present study was designed to evaluate the effects of the foliar application of Si (0, 100, and 200 mg L-1) and three water regimes - no stress (100), mild stress (80%), and severe stress (60%) - on the growth parameters, the yield, and the fruit quality as well as antioxidant status of the tomato. The imposed water stress significantly increased the total soluble solids (TSS), the total acidity (TA), and the flavonoids as well as antioxidant de-fense parameters such as catalase (CAT) and peroxidase (POX), while the growth parameters (plant height and leaf number) and tomato yield were decreased. In contrast, the foliar application of Si (200 mg L-1) re-markably improved the total yield of tomatoes when exposed to water stress by improving the antioxidant en-zyme activities and total flavonoid compounds. In addition, the application of Si could significantly improve the growth parameters (plant height and leaf number) and fruit quality (fruit firmness and size). As a result, the foliar application of Si could be suggested as an effective strategy for imparting water stress resistance in the tomato.