氮肥形态对伴矿景天生长和锌镉吸收性的影响研究

以锌镉超积累植物伴矿景天为供试植物,采用单边根袋法盆栽试验研究了铵态氮肥和硝态氮肥施用对植物根际和非根际土壤中Zn、Cd的化学行为,以及伴矿景天生物量和Zn、Cd吸收性的影响。结果表明,施用硝态氮肥更能提高根际土壤Zn和Cd的生物有效性,显著增大植物体内Zn和Cd浓度(P0.05),增率分别为38.2%和110%,但施用铵态氮肥更有利于促进伴矿景天的生长,增率为49.4%;氮肥形态对伴矿景天生物量的影响显著大于对植物地上部Zn、Cd浓度的效应,施用铵态氮肥显著提高Zn和Cd总吸收量,增率分别为53.3%和123%,施用硝态氮肥对其则无显著影响。施用铵态氮肥较硝态氮肥更能提高伴矿景天的污染土壤Zn、Cd吸取修复效率。

Effects of Nitrogen Forms on Growth and Zn/Cd Uptake of Sedum Plumbizincicola

Different forms of nitrogen affect not only plant growth and metabolism, but also heavy metal absorption by plants. A pot experiment was conducted to study the effects of different nitrogen forms(either NO₃^- or NH₄⁺) on soil solution Zn and Cd concentrations in rhizospheric and bulk soils, and biomass and Zn and Cd uptake of metal hyperaccumulator Sedum plumbizincicola using a unilateral root bag method. Application of NO₃^- increased bio-availability of Zn and Cd in rhizospheric soil and thus the concentrations of Zn and Cd in Sedum plumbizincicola. In NO₃^- treatment, plant Zn and Cd concentrations were respectively 38.2% and 110% greater than the control. However, NH₄⁺ treatment had no effects on bioavailability and plant concentrations of Zn and Cd, but enhanced plant biomass by 49.4%. Different nitrogen forms showed greater effects on the biomass than on plant Zn and Cd concentrations. Treatment with NH₄⁺ significantly increased total amount of plant Zn and Cd uptake by 53.3% and 123%, respectively, but NO₃^- did not. These results indicate that applying ammonium fertilizer would enhance phytoextraction efficiency of Zn and Cd contaminated soils by Sedum plumbizincicola.