Response of Organic Biostimulants and Silicon to Growth, Yield and Quality of Tomato under Soil Salinity Conditions

Abiotic stresses strongly affect plant growth, nutrient composition and quality of production; final crop yield can be really compromised if stress occurs in plants’ most sensitive phenological phases. The present field study was conducted to evaluate the effect of biostimulants on improvement of tolerance and yield of tomato plants exposed to salinity. The tomato field soil condition with pH- 8.7 and EC- 4 dS m-1 was recorded. After the first fruit set of tomato, Organic biostimulant (Organic mix with high concentration of carboxylic acids, containing calcium oxide (CaO), ammonium ligninsulfonate and Zinc) were given by soil drenching and Orthosilicic acid as silicon source by foliar spray at every 10 – 15 days interval. The treatments include Organic biostimulant at 0.3ml/plant & 0.6ml/plant, Orthosilicic acid at 0.2% and 0.4%. The observations were taken during greener and red ripening stage. The biostimulants positively affected the plant height and chlorophyll fluorescence. Biostimulants were allowed to maintain the lower level of electrolyte leakage and osmotic potential within the plant. The activities of catalase (CAT) and superoxide dismutase (SOD) enzymes increased with the increases in salinity: biostimulants thereby kept the lower the level of reactive oxygen species. Under saline conditions due to the ionic imbalance, potassium and calcium content in both the shoots and roots were recorded lower, whereas the sodium content was found to be higher than the control plants. Similarly, a significant increase in total soluble solids and firmness of the fruit was recorded in tomato fruits. Yield characters like fruit number per plant, single plant yield, single fruit weight and flower to fruit ratio were positively affected by the application of biostimulants. The organic biostimulant and Orthosilicic acid administered at a greater dose appeared to be the most effective in our investigation.