plant surface microbiology.pdf

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Anton Hartmann et al.
media are applied. This corroborates the findings of Hengstmann et al. (1999),
who reported similar results in their studies on the microbial community of
the rice rhizosphere. The separation into the three compartments, bulk soil,
ectorhizosphere and rhizoplane/endorhizosphere has to be performed with
great care and actually needs an optimization for each plant and soil type
under study. The degree to which adhering soil particles (ectorhizosphere)
are included in the rhizosphere studies considerably influences the outcome
of the study, since these soil particles are carrying a microbial community
resembling, to a varying extent, the soil situation compared to the root surface
or rhizoplane situation. The microbial population colonizing the root surface
should be approached only after washing the roots free of adhering soil particles.
In conclusion, the way “rhizosphere” is defined by the experimental protocol
is of crucial importance for the results of root colonization studies.
Certainly, in situ and ex situ studies (with the separated rhizosphere compartments)
both complement each other to give a more comprehensive picture.
Although the microscopic in situ approach has the great advantage of
providing detailed spatial information about root surface colonization, quantitative
and qualitative data about the structural and functional diversity of
root colonization can be obtained by a variety of complementary ex situ
approaches.
References and Selected Reading
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