XVI International Botanical Congess

Wetland soil and lake sediments are characterized by oxygen deficiency and redox potentials below -150 mV. One of the most significant adaptation of plants to water-saturated soil or flooding is the increasing rate of atmospheric oxygen transfer through the plant down to the submerged organs. The oxygen release into soil and sediment causes changes in redox potential and has an effect on the bacterial population dynamics. This sediment aeration in relation to the bacterial population was studied on an artificial root surface in anoxic sediment and in constructed wetland planted with tropical and subtropical plant species, before and after applying LAS detergent. After extraction and fixation of bacteria the population was examined by whole cell hybridization with CY3-labeled rRNA-targeted oligonucleotide probes, specific for different taxonomic levels. The presence of physiological active representatives could be localized in distinct zones of sediment samples. Beta-Proteobacteria constituted the numerically most important bacteria, whereas no significant amount for the domain Archaea could be detected.