The Effects of Zinc, Lead and Cadmium Pollution on the Leaf Surface Microflora of Lolium perenne L.

Abstract

The influence of Zn, Pb and Cd contamination on the phylloplane microflora of L. perenne growing at various distances from a smelting complex was investigated. Bacteria, yeasts and filamentous fungi were isolated using a leaf washing method, and relative metal tolerance was assessed by the incorporation of Zn, Pb and Cd salts into the growth media. Numbers of fungal propagules were also assessed by direct observation of leaf segments. Non-pigmented yeasts of the genus Cryptococcus were particularly tolerant to the metals in vitro and in vivo. Bacteria were less tolerant in vitro, but populations in the field were found even under the highest levels of metal contamination. Filamentous fungi were more tolerant than bacteria to heavy metals in vitro but population levels appeared to be particularly influenced by Pb contamination on the leaf surface.