The American pokeweed (Phytolacca americana) is an invasive alien plant species
that occurs in various ruderal habitats in Slovenia and potentially alters the abiotic
properties of soil as well as the composition of microbial communities. The aim of this
master’s thesis was to quantitatively assess the impact of P. americana on the
composition of bacterial, archaeal, and fungal communities in soils of three stands
near Grad Jable (Trzin). Metagenomic sequencing of samples collected beneath P.
americana plants, 0.5 m outside the stands, and 1 m outside the stands revealed
statistically significant differences in the relative abundances of the bacterial phyla
Pseudomonadota, Bacteroidota, Bacillota, and Candidatus Colwellbacteria.
Taxonomic analyses further indicated that the presence of P. americana shifts
bacterial community composition towards changes in nitrogen metabolism. We also
sought to identify the mechanism by which P. americana influences soil microbiome
composition. Based on previous studies, we hypothesized that soil acidification
increases the availability of phosphorus and other nutrients, and in some cases leads to
the hyperaccumulation of Mn and Al. Due to the complexity of the system and the
limited number of samples, the mechanism could not be confirmed. However, we
established that the studied population of P. americana is a hyperaccumulator of Al,
while hyperaccumulation of Mn was not confirmed.
|
