水分条件对湿地植物红蛋吸收镉及其根际土壤中镉化学形态变化的影响

Effect of Water Conditions on Echinodorus osiris Absorption of Cadmium and on Cd Speciation Changes in Rhizosphere Soil

选用对镉（Cd）具有较强耐性和累积性的湿地植物红蛋（Echinodorus osiris）为研究材料,研究了其在不同土壤水分条件和Cd污染水平下,植株对Cd的吸收累积特性以及土壤中Cd化学形态的变化情况。结果表明,根区土壤具有更低的p H值,随着时间的增加,土壤p H呈逐渐升高的趋势。无论在淹水还是非淹水条件下,根区土壤中酸提取态Cd和可氧化态Cd含量均高于非根区土壤,分别提高了1.48%~4.33%和10.25%~16.24%。土壤淹水处理显著提高了红蛋植株生物量、根表铁膜含量、铁膜中Cd含量以及植株体内Cd的含量。总体来说,淹水条件更有利于红蛋植株对土壤中Cd的吸收和累积。

The wetland plant Echinodorus osiris was selected to study its Cd absorption ability under different soil water conditions,and the Cd speciation changes in rhizosphere soil was also researched. The results indicated that there was a lower soil p H value in plant rhizosphere soil,and the soil p H increased as the study time prolonged. In either water-logged or moist soils,the concentration of acid-extractable Cd and Oxidizable Cd was higher in rhizosphere soil than that in non-rhizosphere soil,which were increased by 1. 48 %-4. 33 % and 10. 25%-16. 24 %,respectively. The contents of plant biomass,root Fe-plaque,Fe-plaque bond Cd,and plant Cd were all increased in waterlogged condition. Generally,the water-logged soil condition was more benefit for Echinodorus osiris growth and accumulation of Cd.