• ISSN 1008-505X
  • CN 11-3996/S
杜萌, 李丹丹, 杨军, 杨俊兴, 郭俊娒, 陈同斌. 不同氮肥类型及配施壳聚糖对八宝景天修复镉污染土壤的强化效果[J]. 植物营养与肥料学报, 2020, 26(9): 1714-1723. DOI: 10.11674/zwyf.20011
引用本文: 杜萌, 李丹丹, 杨军, 杨俊兴, 郭俊娒, 陈同斌. 不同氮肥类型及配施壳聚糖对八宝景天修复镉污染土壤的强化效果[J]. 植物营养与肥料学报, 2020, 26(9): 1714-1723. DOI: 10.11674/zwyf.20011
DU Meng, LI Dan-dan, YANG Jun, YANG Jun-xing, GUO Jun-mei, CHEN Tong-bin. Study on different nitrogen forms and combined application of chitosan for enhancing phytoremediation of Cd-contaminated soil by Hylotelephium spectabile[J]. Journal of Plant Nutrition and Fertilizers, 2020, 26(9): 1714-1723. DOI: 10.11674/zwyf.20011
Citation: DU Meng, LI Dan-dan, YANG Jun, YANG Jun-xing, GUO Jun-mei, CHEN Tong-bin. Study on different nitrogen forms and combined application of chitosan for enhancing phytoremediation of Cd-contaminated soil by Hylotelephium spectabile[J]. Journal of Plant Nutrition and Fertilizers, 2020, 26(9): 1714-1723. DOI: 10.11674/zwyf.20011

不同氮肥类型及配施壳聚糖对八宝景天修复镉污染土壤的强化效果

Study on different nitrogen forms and combined application of chitosan for enhancing phytoremediation of Cd-contaminated soil by Hylotelephium spectabile

  • 摘要:
    目的 八宝景天 (Hylotelephium spectabile) 是研究最多的修复Cd污染土壤的植物之一,但还需进一步提高其修复效率以增加其实际应用价值。本研究比较分析了不同氮肥类型以及螯合剂对污染土壤上八宝景天Cd吸收转运的影响及其作用机制,以期为强化八宝景天Cd修复效率提供科学依据和技术支持。
    方法 采用八宝景天进行了盆栽试验,供试土壤为采自四川绵竹的潴育水稻土和广西阳朔的棕色石灰土,两个土壤Cd含量均超过我国农田土壤污染风险筛选值。在氮磷钾肥料施用量一致的条件下,设置生理中性的碳酸氢铵 (NH4HCO3)、生理酸性氯化铵 (NH4Cl)、生理碱性氨水 (NH3·H2O) 以及NH4HCO3配施壳聚糖4个处理。八宝景天生长20天后,测定根、茎、叶生物量和Cd含量,并测定了根际土壤pH、有效态Cd含量以及不同形态Cd含量。
    结果 NH4Cl较NH4HCO3处理降低了两种土壤根际pH,提高了有效态Cd含量。NH4HCO3配施壳聚糖处理对根际土壤酸化效果强于NH4Cl处理,潴育水稻土和棕色石灰土两种土壤根际有效态Cd含量分别较NH4Cl处理提高18.6%和15.5%。此外,与施用NH4HCO3相比,NH4Cl提高了两种土壤水溶态和弱酸提取态Cd含量,而NH4HCO3配施壳聚糖处理虽使水溶态Cd含量增加,但由于壳聚糖与土壤中Cd形成稳定性较强的络合物,同时促进了八宝景天对弱酸提取态Cd的吸收,因此其根际弱酸提取态Cd含量无显著差异。NH4HCO3、NH4Cl和NH3·H2O 3种氮肥类型对八宝景天生长和Cd吸收转运的促进作用无显著差别,而NH4HCO3配施壳聚糖则使八宝景天生物量较其他施氮处理显著提高了29.6%~79.8%,同时NH4HCO3配施壳聚糖对八宝景天Cd吸收转运的促进作用受土壤类型、理化性质和污染程度的影响,对棕色石灰土上八宝景天各部位Cd含量、生物富集系数和转运系数分别提高了16.0%~143.4%、45.8%~137.5%和25.3%~81.6%,而在潴育水稻土上促进作用均较小。
    结论 在施氮量一致的情况下,施用生理酸性氮肥有利于促进八宝景天Cd吸收,肥料和壳聚糖配施可能是强化八宝景天Cd修复效率的有效措施。其强化效果在中性偏碱性土壤上好于在酸性土壤上。

     

    Abstract:
    Objectives Hylotelephium spectabile is one of the most potential plants used for remediating Cd-contaminated soil, while further measures still needed to improve its phytoextraction efficiency, and thereby increase the practical value in phytoremediation of Cd-contaminated field. This study compared the effect of different nitrogen forms and chelator on Cd absorption and translocation of H. spectabile in Cd-contaminated soils as well as the control mechanism.
    Methods A pot experiment of H. spectabile was conducted using two typical Cd-contaminated soils in southern China, waterloggogenic paddy soil (pH 7.07) was collected from Mianzhu City, Sichuan Province and brown rendzina (pH 6.0) from Yangshuo County, Guangxi Region. Under the same fertilizer rates of nitrogen, phosphorus and potassium, application treatments of physiological neutral N (NH4HCO3), physiological acid N (NH4Cl), physiological alkaline N (NH3·H2O) and combined application of NH4HCO3+chitosan (NH4HCO3+chitosan) were setup. After the H. spectabile was transplanted and cultured for 20 days, the dry weight and Cd concentrations of roots, stems and leaves were investigated. The soil pH, available Cd content and the contents of different Cd forms in rhizosphere soil were measured.
    Results The pH in rhizosphere of two tested soils was significantly decreased, while the available Cd concentrations were significantly increased with addition of NH4Cl in comparison with NH4HCO3. In addition, combined application of NH4HCO3+chitosan possessed more superior ability in acidization of rhizosphere soils than NH4Cl, which significantly increased the available Cd concentration in two rhizosphere soils by 18.6% and 15.5%, respectively. Compared with NH4HCO3, addition of NH4Cl also significantly increased the water soluble and acid extractable Cd contents of two tested soils. However, although combined application of NH4HCO3+chitosan increased the water-soluble Cd concentration, no significantly differences were found in acid extractable Cd when compared to NH4HCO3 treatment. The results may be attributed to that chitosan led to formation of relatively stable complex with Cd in soils, and promoted growth and Cd absorption of acid extractable Cd in rhizosphere soils. Application of three nitrogen forms showed no obvious differences in promoting growth and Cd absorption and translocation of H. spectabile, while combined application of NH4HCO3+chitosan significantly increased the dry biomass of different tissues of H. spectabile by 29.6%–79.8% compared with NH4HCO3. Furthermore, the promotion effects of NH4HCO3+chitosan treatment on Cd absorption and translocation of H. spectabile varied with soil types, pH, and contamination levels. In brown rendzina, the Cd concentrations in different tissues of H. spectabile, the bioconcentration factors and translocation factors were significantly increased by 16.0%–143.4%, 45.8%–137.5%, and 25.3%–81.6% respectively, compared with NH4HCO3, while in water loggogenic paddy soil the promotion effects were not significant.
    Conclusions Application of physiological acid nitrogen is beneficial to Cd absorption by H. spectabile under the condition of same nitrogen fertilizer rates, and the combined application of nitrogen fertilizer and chitosan may be an effective measure for enhancing phytoremediation of Cd-contaminated soils using H. spectabile, which is more effective in neutral or alkaline soil than in acid one.

     

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