Abstract:

A pot experiment was conducted to study effects of Citric acid (CA) and EDTA on physiological characteristics and Cd accumulation of R. communis. Results show that the application of EDTA alone significantly reduced the biomass of shoots and the content of chlorophyll of R. communis, evidently affected the activity of antioxidant enzyme in leaves of the plant(P<0.05), and even inhibited the activities of SOD and POD, when the application rate reached 10 mmol•kg-1. The application of EDTA and CA together reduced the toxicity of EDTA to R.communis to a certain extent, the effect of EDTA, at 1 or 5 mmol•kg^-1, lowering the biomass of shoots and the content of chlorophyll of R.communis and the effect of EDTA, at 1 mmol•kg^-1, increasing the content of MDA in the plant. The application of EDTA alone, at 5 mmol•kg-1, brought Cd accumulation and transfer capacity of the plant to the peak, two times as high as in CK. However, once 2 mmol•kg^-1CA was applied in combination, the effect of EDTA reached a new peak, 3 times as high as in CK. Therefore, combined application of EDTA with Ca should be a practice of great potential in enhancing the effect of R.communis remedying Cd polluted soils.

Key words: Ricinus communis, CA, EDTA, biomass, Cd