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Arbuscular Mycorrhizae Fungi: A Tool For Sustainable Agriculture. Varaprasad Kolla et al

host. Further, thin-walled structures are also formed in It has also been reported that inoculation with AMF in-
the root cortex which are of different shape and size, creases the photo-availability of micronutrients like Cu
they function as storage organs, known as vesicles. and Zn and increase the biomass accumulation in plants
by enhancing signifi cantly the concentration of macro
SIGNIFICANCE OF AMF IN CROP PRODUCTI- and micronutrients, leading to increased photosynthate
VITY production. Improved levels of protein, Fe, and Zn were
The symbiosis of AM has raised the standards of com- observed in mycorrhizal chickpea (20).
mercial application, improved agricultural practices
and crop productivity. Studies have reported that AMF The water-stable aggregates formed by the produc-
colonization of the plant roots improves plant nutrition tion of glomalin on AMF colonization improves the
by various mechanisms. They form a hyphal network soil structure, promoting better provisions for the sur-
with the plant root which signifi cantly enhances ac- vival of a plant, especially in adverse or low-nutrient
cess to larger soil surface areas and increases the sur- environments. Studies suggest that the fungi may also
face absorbing capability of the host root. Colonization protect plant roots from invasion by plant parasitic pa-
with AMF increases the availability, translocation and thogens (PPN) by altering the root morphology (21),
uptake of various nutrients like P, K, Fe, Zn, and Cu competing for space and nutrition (22-23), by systemic
and trace elements like boron and molybdenum to the suppression of nematode infection (24), and by altering
plant (12-14). They increase the capability of the plant root exudation composition and level which can have
to absorb phosphorus, an element mostly inaccessible an effect on the hatching, motility and chemotaxis of
to plants and mobilized organically bound to nitrogen. PPN in the surrounding rhizosphere (25), thus confe-
(15). AMF help the plant in better nutrient absorption rring resistance to plant pathogens and diseases (26-28).
from nutrient defi cit soils, they facilitate selective up- Colonization with AMF infl uences plant exudation pat-
take of ions under stressed conditions in phosphorus and terns that alter the microfl ora of the rhizosphere which
water-defi cient soils, thus providing protection from ex- could infl uence plant growth, stability, survival, and
tremes in the environment. In many cases AMF have yield (29-31). AMF are known to associate synergisti-
themselves conferred resistance to stress conditions like cally with other benefi cial micro-organism and improve
high salinity and metals (16-19). AMF can help transfer plant growth. AMF act as biofertilizers, bioprotectants,
about 20–75% of the total N uptake to its host plants. or biodegraders and hence can alter plant productivity
Assimilation and absorption of inorganic phosphate is under unstressed and stressed regimes by providing es-
assisted by the extra-radicle hyphae. sential inorganic nutrients to host plant (32-33). Figure
1 shows the impact of AMF on crop productivity.

Figure 1. The impact of AMF on crop productivity

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Rev. Asoc. Col. Cienc.(Col.), 2020; 32: 63-76.