Agriculture Reference
In-Depth Information
dration of tissues thereby, helping the plants to grow normal even under
stress conditions. Reducing, nonreducing and total sugars are enhanced in
mycorrhizal plants compared to control.
14.3.4 REMEDIATION OF SOIL POLLUTANTS
Mycorrhizal fungal strain tolerant to heavy metals has provided evidence
for their rapid adaptation to contaminated soils (Bhalerao, 2013; Khan,
2007). Several heavy metal tolerant AMF strains have been isolated, that
is, cadmium-tolerant
Glomus mosseae
isolates. Copper (Cu) was absorbed
and accumulated in the extraradical mycelium of AMF isolates, as ob-
served in a study with
Glomus
spp. thus, protecting the host from dam-
age. Arbuscular mycorrhizal fungi tolerant to aluminum have also been
reported.
Glomus caledonicum
is the promising mycorrhizal fungus for
bioremediation of heavy metal contaminated soil, while it can uptake and
translocate of uranium towards the roots. Mycorrhizae are also found to
ameliorate toxicity of the trace metals in polluted soils. Since heavy met-
al uptake and tolerance depend on both plant and soil factors, including
soil microbes, interactions between plant root and their symbionts such
as AM fungi can play an important role in successful survival and growth
of plants in contaminated soils. Mycorrhizal associations increase the ab-
sorptive surface area of the plant due to extrametrical fungal hyphae ex-
ploring rhizospheres beyond the root-hair zone, which in turn enhances
water and mineral uptake. AM fungi can further serve as a filtration barrier
against transfer of heavy metals to plant shoots. The protection and en-
hanced capability of uptake of minerals result in greater biomass produc-
tion, a prerequisite for successful remediation.
14.3.5 RESTORATION OF DEGRADED AREAS
The soils of degraded sites are low in available nutrients and lack the N
2
-
fixing bacteria and mycorrhizal fungi usually associated with root rhi-
zosphere. As such, land restoration in semiarid areas faces a number of
constraints related nutrient and water shortage. Mycorrhizae enhance the
ability of the plant to coop with water stress situations, nutrient deficiency
and drought, mycorrhizal inoculation with suitable fungi has been pro-
posed as a promising tool for improving restoration success in semiarid
