The effect of silicon on membrane integrity and antioxidative pigments on Echium amoenum that exposed to cadmium stress

Some researchers reported that silicon (Si) increase tolerance in some higher plants against biotic and abiotic stress. The beneficial effects of Si are mainly associated with its high deposition in plant tissue and enhancing their strength and rigidity. We investigated the role of Si against cadmium stress in (Echium amoenum Fisch. & C.A.Mey.) in greenhouse condition. When the seventh leaf appeared, plants were pretreated with five levels of Si: 0,0.2, 0.5, 0.7and 1.5 mM Si (as sodium trisilicate, Na2(sio2)3) and then the plants were treated with two levels of Cd (30 and 90 mM). The effects of Silicon and Cd were investigated on some physiological and biochemical parameters such as: lipid peroxidation (malondialdehyde (MDA) and other aldehydes), anthocyanin and flavonoid content. Our results showed that Cd significantly increased MDA, other aldehydes, antocyanin and flavonoids content in Echium and silicon offset the negative effect and increased tolerance of Echium against Cd stress. From this results we concluded that Si increase membrane integrity and antioxidative ability in this plant against cd stress.