Importance of Myriophyllum alterniflorum D.C., an aquatic macrophyte, in biomonitoring of trace metal pollution in running freshwater
Abstract
Many pollutions in freshwater could be assessed by biological indicators ranging from microscopic to macroscopic level. Insect larvae and diatoms are commonly used for many years but aquatic macrophytes are still unknown and poorly used. Somes taxa like Elodea, Potamogeton, Hydrilla and Myriophyllum were studied for their biomonitoring capabilities and/or their bioaccumulation potential. However few studies focused on biomarkers and to our knowledge, all of them were conducted only on natural populations. The aim of this study was to review the use of aquatic macrophytes as biomonitors for trace metals pollution in freshwater and to highlight the high potential of macrophytes physiological biomarkers (CAT, APX, chlorophylls, carotenoids, PC....) in the early detection of pollution. Moreover some preliminary results on in vitro culturing of a running freshwater species, Myriophyllum alterniflorum, will be presented. Watermilfoil cloning could allows us (1) to use this species in bioindication studies without endangering natural populations, (2) to compare plant reaction to trace metal pollution in situ and ex situ without genotypic variation and (3) to restore degraded areas. A large screening of potentially Cu and/or Cd early responding biomarkers of M. Alterniflorum is in progress using in situ and ex situ conditions. This study will lead to define the most useful endpoints to detect early pollutions even at low concentrations.