Effect of Silicon nutrition on alleviation the detrimental effects of nickel stress in (Ocimum basilicum)

Nickel is an essential microelement for plant growth, but upper levels of this element serve as heavy metal which create toxic effects on plants and human. Application of mineral nutrition is a useful strategy for overcoming of this serious problem. In order to investigate the effects silicon nutrition on growth and physiology indices of basil (Ocimum basilicum L.) under nickel stress condition a factorial experiment based on completely randomized design with four replication was conducted in Research Greenhouse of Mohaghegh Ardabili University at 2014-2015. Experimental factors included nickel stress(0, 75, 100 and 150 ppm) and foliar spraying of plants with 1Mm concentration of silicon and control (spraying with water). During this experiment traits such as plant height, plant dry weight, root and stem dry weight, leaf and stem number, leaf area, chlorophyll index, electrolyte leakage, relative water contents, photosynthetic pigments and antioxidant enzymes and nickel accumulation in root and aerial part of plants were measured. Results indicated that the effect of nickel stress on all of traits were significant. At 150 ppm concentration of nickel, vegetative growth criteria and biochemical characteristic of basil plants reduced significantly. Foliar spraying of silicon could be alleviated the unfavorable effects of nickel stress via increases in chlorophyll b, carotenoid and carbohydrate content of leaves and increases in catalase enzyme activity also reduction in nickel content in aerial part of plants.