Corn and wheat plants were grown in a nutrient culture solution at four levels of phosphorus (0, 0.12,0.60 and 3.0 mmol L-1) and two levels of cadmium (0 and 4.0 pmol L--1) in greenhouse for a 18-day period.The concen...Corn and wheat plants were grown in a nutrient culture solution at four levels of phosphorus (0, 0.12,0.60 and 3.0 mmol L-1) and two levels of cadmium (0 and 4.0 pmol L--1) in greenhouse for a 18-day period.The concentrations of phosphorus and cadmium in cell wall, cytoplasm and vacuoles of roots and leaveswere examined by cell fractionation techniques. With increasing phosphorus in medium, the contents of Pin cell wall, cytoplasm and vacuoles of corn and wheat roots and leaves increased. The highest content of Pwas observed in cell wall, next in vacuoles, and the lowest in cytoplasm. The wheat subcellular fractions inboth roots and leaves had higher concentrations of phosphorus than those of corn. Increasing phosphorus inmedium significantly inhibited the intracellular Cd accumulation in both species. However, at P concentrationup to 3.0 mmol L--1, the Cd content in cell wall was increased. Increasing phosphorus resulted in reductionof the subcellular Cd content in corn and wheat leaves. Compared with corn, the wheat roots had a higherCd content in the cell wall and vacuoles and a lower in cytoplasm, while in leaf subcellular fractions thewheat cell had a higher Cd content in its vacuoles and a lower one in its cytoplasm. The results indicate thatphosphorus may be involved in sequestration of Cd ionic activity in both cell wall and vacuoles by forminginsoluble Cd phosphate.展开更多
文摘Corn and wheat plants were grown in a nutrient culture solution at four levels of phosphorus (0, 0.12,0.60 and 3.0 mmol L-1) and two levels of cadmium (0 and 4.0 pmol L--1) in greenhouse for a 18-day period.The concentrations of phosphorus and cadmium in cell wall, cytoplasm and vacuoles of roots and leaveswere examined by cell fractionation techniques. With increasing phosphorus in medium, the contents of Pin cell wall, cytoplasm and vacuoles of corn and wheat roots and leaves increased. The highest content of Pwas observed in cell wall, next in vacuoles, and the lowest in cytoplasm. The wheat subcellular fractions inboth roots and leaves had higher concentrations of phosphorus than those of corn. Increasing phosphorus inmedium significantly inhibited the intracellular Cd accumulation in both species. However, at P concentrationup to 3.0 mmol L--1, the Cd content in cell wall was increased. Increasing phosphorus resulted in reductionof the subcellular Cd content in corn and wheat leaves. Compared with corn, the wheat roots had a higherCd content in the cell wall and vacuoles and a lower in cytoplasm, while in leaf subcellular fractions thewheat cell had a higher Cd content in its vacuoles and a lower one in its cytoplasm. The results indicate thatphosphorus may be involved in sequestration of Cd ionic activity in both cell wall and vacuoles by forminginsoluble Cd phosphate.
