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作 者 ：李廷强¹;朱恩²;杨肖娥¹;申屠佳丽¹

期 刊 ：应用生态学报 2008年 19卷 04期 页码：838-844

关键词：东南景天；

摘 要 ：采用盆栽和模拟试验研究了锌超积累植物东南景天根际土壤可溶性有机质(DOM)对土壤锌吸附解吸的影响.结果表明: 采用矿山土壤种植锌超积累植物东南景天后，根际土壤水溶性锌和乙酸铵提取态锌含量显著降低，而非根际土壤有效锌无明显变化.与不种植东南景天的对照土壤相比，根际土壤pH值降低了0.3个单位，有机质和DOM含量分别提高13.6%和20.9%.东南景天根际DOM对土壤锌吸附解吸的影响方式和程度与土壤类型有关.与对照DOM相比，在矿山土、黄筋泥和黄松土中，添加根际DOM使锌的最大吸附量(X_m)分别降低了17.8%、21.9%和27.7%，而非根际DOM对锌的最大吸附量没有影响.在3种供试土壤中添加根际DOM促进了锌的解吸，其中以黄松土最明显.东南景天根际DOM能降低土壤锌吸附容量，减少土壤对锌的吸附，促进吸附态锌的解吸，从而提高了根际锌的生物有效性.

Abstract:The study with pot experiment and simulation test showed that after planted hyperaccumulator Sedum alfredii Hance on mining soil, the water soluble Zn and NH₄OAc extractable Zn in rhizosphere were decreased obviously, while the available Zn in nonrhizosphere had less change. The pH value of rhizosphere soil was decreased by 0.3 units, whereas the organic matter and dissolved organic matter (DOM) contents were increased by 13.6% and 20.9%, respectively, compared with the soil without S. alfredii. The effects of DOM from S. alfredii rhizosphere on Zn absorption and desorption varied with the kinds of test soils. After the addition of rhizosphere DOM, the maximal absorption capacity (X_m) of mining soil, quaternary red clay soil, and fluaviomarine yellow loamy soil was reduced by 17.8%, 21.9% and 27.7%, respectively, whereas the addition of nonrhizosphere DOM had no effects on Zn absorption. The Zn desorption in the three soils, especially in fluavio-marine yellow loamy soil, was promoted by the addition of rhizosphere DOM. It was indicated that the DOM from S. alfredii rhizosphere could reduce the maximal absorption capacity and accelerate the desorption of adsorbed Zn, and thus, increase the Zn mobility and bioavailability.

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