Effects Of Selenium Zinc And Silicon On Reducing Cadmium In Potato

Potato(Solanum tuberosum L.),as a grain,vegetable,feed and industrial raw material crop,plays an important role in promoting economic development and ensuring food security.Southwest China is one of the main potato producing areas in China,including Enshi in Western Hubei,Western Sichuan Plateau,Yunnan and Guizhou.Cadmium(Cd)pollution is widespread,and the Cd content of potato tubers in some areas exceeds the standard.Cd is a ubiquitous and highly toxic heavy metal element in the natural environment.Cd pollution caused by human activities has become a global environmental problem.The human body mainly ingests Cd through the food chain,so reducing Cd in food is very important to alleviate Cd toxicity.Through pot experiments,this study explored the effects of different kinds,concentrations of trace elements and their application methods on Cd content in different parts of potato,in order to provide a theoretical basis for scientific and reasonable reduction of Cd in potato.The results are as follows:1.The application of 5 mg/kg Cd inhibited the growth of potato and reduced the tuber quality.Compared with no application of Cd,5 mg/kg Cd reduced the net photosynthetic rate and transpiration rate by 76.0% and 45.0% respectively.The specific growth indexes were as follows: in different growth stages,5 mg/kg Cd reduced potato plant height by 9.8%-13.4% and stem diameter by 8.4%-11.3%.5 mg/kg Cd reduced the contents of Vitamin C,crude protein and non-structural carbohydrate in potato tubers by22.4%,21.9% and 23.1% respectively.2.Different kinds of trace elements and application methods can reduce the content of Cd in potato.Comparison of trace elements in different species with the same application method,basal application of selenium(Se)had the best effect on reducing Cd,and the content of Cd in tubers decreased by 17.6% compared with that only applied with Cd;In the spraying treatment,spraying zinc(Zn)had the best effect on reducing Cd,and the Cd content of tubers decreased by 29.4% compared with only applying Cd.Compared with different application methods of the same element,the effect of spraying was better than that of base application,and the effect of spraying Zn was the best.Overall,the decrease of Cd content in potato tubers under spraying treatment was 1.4-3.0 times that of basal application.The Cd enrichment coefficient of potato tubers under spraying treatment also decreased more than that under base application treatment.Among them,the Cd enrichment coefficient of potato tubers after spraying Zn treatment decreased the most,with a decrease of 33.3%.Silicon(Si)treatment increased the transport coefficient of Cd from root to stem and leaf by 55.4%,but decreased the transport coefficient of Cd from stem and leaf to tuber by 25.0%.3.There were significant differences in the effects of different concentrations of Se,Zn and Si on reducing Cd content in potato tubers.After spraying 450 mg/L Zn,the content of Cd in potato tubers was the lowest,which was 30.6% lower than that of Cd only.Compared with the same kind of trace elements,the content of Cd in tubers sprayed with 5 mg/L Se,450 mg/L Zn and 1500 mg/L Si decreased the most.Spraying trace elements can not only reduce the content of Cd in potato tubers,but also improve the activities of antioxidant enzymes in leaves and enzymes related to nitrogen metabolism in tubers.After spraying 450 mg/L Zn,the contents of malondialdehyde and proline in potato leaves were the lowest,which were 38.3% and 32.8% lower than that of Cd only.Compared with other concentrations of the same medium and trace elements,the activities of peroxidase(POD),catalase(CAT)and superoxide dismutase(SOD)were the highest when spraying 5 mg / L Se and 450 mg/L Zn;The nitrate reductase(NR)activity of 1500 mg/L Si treatment was the highest,which was 37.5% higher than that of Cd only;The activity of glutamine synthetase(GS)in the treatment of spraying 5mg/L Se was the highest,which was 64.3% higher than that of applying Cd only.In conclusion,5 mg/kg Cd inhibited the growth of potato and reduced the quality of potato.The application of Se,Zn and Si reduced the Cd content of potato tubers.The spraying effect was better than the base application,and the best spraying concentrations were Se: 5 mg/L,Zn: 450 mg/L and Si: 1500 mg/L.