Assessing the Ecological Significance of Arbuscular Mycorrhizal Fungi in Ethiopian Plant Communities and Their Contribution to Agro-Ecosystem Resilience

Abstract

In this review it has been tried to surface out the role of arbuscular mycorrhizal fungi to the agro ecosystem. Particularly, AMF's contribution to stabilize soil fertility, reduction of use of phosphate fertilizer, increase in plant tolerance against biotic & abiotic stresses, and enhancement of quality plant production was reviewed. Besides, this review has attempted to compile several efforts, conducted so far in the study of AMF diversity and abundance at different land use patterns in Central, Rift Valley, Northern and Southern Ethiopia. AMF diversity, plant-fungus assemblages, is generally influenced by the slope, soil physico-chemical nature. Especially soil PH, availability of extractable chemicals such as calcium & potassium, its cation exchange capacity, electrical conductivity and field capacity are determinant factors. However, the effects of factors such as plant community in the AMF community composition are less clear. In general, infectivity and diversity of AMF communities is often reduced in disturbed habitats such as agro ecosystems or post-mining sites. AMF are considered to have low specificities of association with host species, but this conclusion is mostly based on experiments in which individual isolates of fungal species are grown separately. When fungi are examined as a community, evidence suggests fungal growth rates are highly host-specific, hence it can be concluded that ecological specificity applied to some arbuscular mycorrhizal associations. However, the competitive balance between AM fungal species in terms of their ability to colonize roots may be affected by environmental conditions. This specificity of fungal response could contribute to the maintenance of diversity within the AMF community. Regarding the seasonal diversity of AMF, evidence has showed that fungal spore density differs seasonally, with some fungi sporulating in late spring and others sporulating at the end of summer. As the spores represent the dormant state of the fungus, the physiologically active state is most likely the mirror image of the seasonal spore counts. Though scholars in Ethiopia have contributed tremendously, yet there are still lots of tasks which are required to be carried out to help respond the outstanding questions allied with fungi-plant assemblages.