Manier Nicolas, Deram Annabelle, Broos Kris, Denayer Franck-Olivier, Van Haluwyn Chantal
Institut Lillois d'Ingénierie de la Santé (ILIS), EA 2690, 42, rue Ambroise Paré, 59120 Loos, France.
J Environ Qual. 2009 Feb 25;38(2):685-92. doi: 10.2134/jeq2008.0013. Print 2009 Mar-Apr.
The morphological effects of heavy metal stress on the nodulation ability of Rhizobium spp. and growth of white clover (Trifolium repens L.) were studied in the laboratory under controlled conditions. Fourteen topsoils were collected from an area with elevated metal concentrations (Cd, Zn, and Pb). White clover was cultivated using a specialized "rhizotron" method to observe the development of root and nodule characteristics. Results show effects of increasing heavy metal concentrations on nodulation development, especially the nodulation index (i.e., the number of nodules per gram of the total fresh biomass). A significant decrease in nodulation index was observed at about 2.64 mg Cd kg(-1), 300 mg Zn kg(-1), and 130 mg Pb kg(-1) in these soils. The sensitivity of the nodulation index in relation to other morphological characteristics is discussed further. It is proposed that the nodulation index of white clover is a suitable bioindicator of increased heavy metal concentrations in soil.
在实验室可控条件下，研究了重金属胁迫对根瘤菌结瘤能力及白三叶草（Trifolium repens L.）生长的形态学影响。从金属浓度（镉、锌和铅）升高的区域采集了14种表层土壤。采用专门的“根箱”方法种植白三叶草，以观察根和根瘤特征的发育情况。结果表明，重金属浓度增加对结瘤发育有影响，尤其是结瘤指数（即每克总鲜生物量的根瘤数）。在这些土壤中，当镉含量约为2.64 mg/kg、锌含量为300 mg/kg、铅含量为130 mg/kg时，结瘤指数显著下降。进一步讨论了结瘤指数相对于其他形态特征的敏感性。提出白三叶草的结瘤指数是土壤中重金属浓度增加的合适生物指标。
