EFFECTS OF SEED SOAKING WITH SELENIUM AND ZINC ON QUALITY AND CADMIUM CONTENT OF RADISH (RAPHANUS SATIVUS L.) GROWN IN CADMIUM-CONTAMINATED SOIL

Radish (Raphanus sativus L.) is a nutritious root vegetable planted worldwide. Based on the theories that selenium (Se) is a beneficial element and zinc (Zn) is an essential element for plant growth. In this study, a field experiment was conducted to evaluate the effects of seed soaking with Se (0, 5, 20 mg/L) or/and Zn (0, 25, 100 mg/L) on the growth, cadmium (Cd) content and nutritional quality of radish root grown in Cd-contaminated soil (CK: 0.044 mg/kg; Cd-M: 0.360 mg/kg; Cd-H: 0.950 mg/kg). The findings in this study confirmed that seed soaking with Se or Zn effectively reduced Cd accumulation in radish. At Cd-M level, Cd content was decreased by 20.59% (or 27.36%) soaked with Se 5 mg/L (or 20 mg/L) alone, and decreased by 4.74% (or 28.31%) soaked with Zn 25 mg/L (or 100 mg/L) alone. At Cd-H level, Cd content was decreased by 16.33% (or 9.59%) soaked with Se 5 mg/L (or 20 mg/L) alone, and decreased by 27.66% (or 23.44%) soaked with Zn 25 mg/L (or 100 mg/L) alone. Meanwhile, the quality was not reduced and even enhanced both at Cd-M and Cd-H levels. In addition, co-soaking with Se and Zn had no synergistic effect on reducing Cd content in radish edible parts and guaranteeing the quality of radish edible parts, nevertheless, seed soaking with 100 mg/L Zn + 5 mg/L Se indicated outstanding efficiency on that. At Cd-M level, seed soaking with 100 mg/L Zn + 5 mg/L Se enhanced soluble sugar and vitamin C content by 12.16%, 20.86%, respectively, and reduced nitrate and Cd content by 12.01%, 18.42%. At Cd-H level, seed soaking with 100 mg/L Zn + 5 mg/L Se enhanced soluble sugar, soluble protein and vitamin C content by 38.64%, 10.53%, and 5.09%, respectively, meanwhile, reduced nitrate and Cd content by 16.01%, 14.97%.