Silicon alleviates cadmium stress in basil (Ocimum basilicum L.) through alteration of phytochemical and physiological characteristics

摘要

Cadmium (Cd) toxicity can disorder normal plant growth and development causing catastrophic crop failures and food insecurity. Silicon (Si) plays a pivotal role in mitigation of toxic stress by influencing plant physiological and metabolic responses. This attempt was conducted to evaluate the efficiency of Si on physio-biochemical traits and secondary metabolites production of basil plant under Cd stress. In this direction, the plants were grown in greenhouse condition and subjected to various concentration of Cd (0, 25, and 50 mg kg-1 soil) and foliar of Si solutions (0, 1 and 2 mM) alone and/or in combination. Cd toxicity amplified activities of defense enzymes and compounds, oxidation of cell membrane, and production of secondary metabolites. With increasing Cd toxicity in soil, the level of Cd dramatically raised in both shoot and root of basil. The results indicated that Si has an anti stress effect on Cd-contaminated basil plants. Thereupon, Si supply alleviated Cd toxicity and promoted basil growth by reducing Cd accumulation, root-to-shoot Cd transport, Malondialdehyde (MDA) content, electrolyte leakage (EL) percentage and increasing activity of antioxidant enzymes, concentration of phenolics and flavonoids, as well as the amount of caffeic, chicoric and rosmarinic acids.