Influence of atmospheric zinc deposition on different genotypes of the moss Atrichum undulatum

Granted to Ingeborg Lang (AUT) and Marko Sabovljevic (SRB)
(Scientific & Technological Cooperation between Austria and Serbia)  

Duration of project: 01.07.2018 - 30.06.2020
Project No: SRB 15/2018 

Abstract

Atmospheric pollution is one of the main threats to modern world. It influences humans but also other life forms including mosses. However, mosses are often treated as indicator species for air pollution and widely used in atmospheric heavy metal deposition measurements. The reason for this is the lack of absorbance from the substrate due to an absence of roots (rhizoids are just for anchoring). Nutrients are taken up by the whole aerial surface (moss body) which does not possess a cuticle and is therefore not preventing contact with pollutants as in vascular plants. Though, it is not known if there are significant differences in heavy metal attachments to the moss body received by rain deposition from the atmosphere among different species or even different genotypes. On the other hand, it is widely accepted that life forms (acrocarps vs. pleurocarps) and the peculiar cell wall properties of bryophytes should be considered in an explanation of the amount of bound metal ions.
Possible mechanisms involve cation exchange capacities and the adsorption to the cell wall (Lang & Wernitznig 2011) which have been shown to be species and metal dependent (Sassmann et al., 2015a). To date, no experiments have been conducted under controlled conditions (i.e. to exclude synergistic or antagonistic effects of the environment and other moss-cohabitants) to explain the mechanisms and differences in heavy metal accumulation among species and among genotypes within the same species. Thus, the aseptic in vitro cultures of dozen genotypes of the moss Atrichum undulatum from different areas of Europe will be used in experiments with Zn(II)-enriched rain simulation . This will allow to analyse the Zn(II) binding pattern(s) and detect any differences among the populations. Zn-binding and localization in the moss tissues will be tested using confocal microscopy with aid of the fluorescent marker (FluoZin™-3). The amount of Zn attached to the moss tissue will be measured by X-ray microanalysis on the Scanning Electron Microscope (EDX-SEM). The influence of Zn(II) on the ploidy level of the different organs/tissues (via endoreduplication) of the tested moss A. undulatum will be documented by flow cytometry. The correlation of the moss survival and Zn-adsorption with endopolyploidy will be investigated. Endopolyploidy and polyploidy in general often is influenced by external biotic and abiotic factors, one of those being heavy metals.