and benefits to plant–microbe interactions in
J. A. W. Morgan, G. D. Bending and P. J.
Warwick HRI, University of Warwick, Wellesbourne,
Warwick CV35 9EF, UK.
This review looks briefly at plants
and their rhizosphere microbes, the chemical communications
that exist, and the biological processes they sustain.
Primarily it is the loss of carbon compounds from
roots that drives the development of enhanced microbial
populations in the rhizosphere when compared with
the bulk soil, or that sustains specific mycorrhizal
or legume associations. The benefits to the plant
from this carbon loss are discussed. Overall the general
rhizosphere effect could help the plant by maintaining
the recycling of nutrients, through the production
of hormones, helping to provide resistance to microbial
diseases and to aid tolerance to toxic compounds.
When plants lack essential mineral elements such as
P or N, symbiotic relationships can be beneficial
and promote plant growth. However, this benefit may
be lost in wellfertilized (agricultural) soils where
nutrients are readily available to plants and symbionts
reduce growth. Since these rhizosphere associations
are commonplace and offer key benefits to plants,
these interactions would appear to be essential to
their overall success.
Micro-organisms, mycorrhiza, nodulation, nutrition,
phosphate, rhizosphere, pathogens.