When considering the CLPP results of all carbon sources individually,
more detailed distinctions can be made. Fig. 5A shows a
linear discriminant analysis (LDA) of the Abs590nm values after 94 h
of incubation, using the data of harvesting at 16 and 53 days.
Additionally, group means for all sample types are depicted with a
probability ellipse (standard deviation, p ¼ 0.68), and the font size
of the carbon sources corresponds to the score of each source on a
SIMPER analysis distinguishing between AgNP-exposed and nonexposed
bulk soil samples at these harvesting points. Similarly to
the results in Fig. 3, the findings demonstrate that at these other in the non-exposed samples than in the AgNP-exposed
samples. However, at these harvesting points, the carbon use
pattern of AgNP-exposed rhizosphere was more different from that
of the non-exposed rhizosphere than was the case at harvesting
points 16 and 53 days. Nonetheless, this difference did not result
from a similar change in carbon use pattern as in the bulk soil, as
indicated by the SIMPER results in Fig. 5A and B. While C-sources
like D-xylose, phenylethylamine and 4-hydroxy benzoic acid
seemed to contribute the most to the difference between nonexposed
and AgNP-exposed bulk soil at harvesting points 16 and
53 days, it were mainly glycogen, alpha-cyclodextrin and itaconic
acid that distinguished non-exposed and AgNP-exposed rhizosphere
at 39 and 75 days. The general pattern shown by the LDAs
pointed out that no C-sources were strictly typical for any
sample type in general, and that differences were mainly caused
by generally lower C-oxidation values in AgNP-exposed samples,
compared to non-exposed samples.