The multiple effects of exogenous silicon on alleviation of cadmium toxicity in Raspberry (Rubus idaeus L.)

Abstract

Abstract Aims Cadmium (Cd) is a heavy metal, which is highly highly toxic to humans and plants. Exogenous silicon (Si) has been shown to alleviate Cd toxicity in various plant species, but the mechanism in raspberry has not been cleared. Methods A pot experiment was adopted to evaluate the effects of Si on the growth, biochemical parameters, ultrastructure and Cd content of Cd-treated raspberry plants. In this experiment, raspberry was treated with three levels of cadmium (0, 5, and 10 mg kg−1), and each level of cadmium was treated with three levels of silicon (0, 100 and 200 mg kg-1). Results The exogenous application of Si (especially at 200 mg kg-1 level) obviously enhanced plant growth, photosynthetic pigments, gas exchange attributes, and ameliorated Cd-induced ultrastructural alterations by reducing malondialdehyde (MDA) content and further increasing enzymatic antioxidative defense system activity. Si applied also reduced available Cd content in the soil, resulting in lower Cd content in plant tissues and the translocation factor. Conclusions This study revealed that external application of Si alleviates the adverse effect of Cd by enhancing the growth of plant, increasing photosynthesis, strengthening the antioxidant defense systems, reducing oxidative injury, amending Cd-induced ultrastructural changes and reducing Cd bioavailability, thereby decreasing Cd uptake and translocation with different Cd levels in raspberry.