Arbuscular mycorrhizal fungi spore density and species diversity varied within plants species and between dry Afromontane forests in northwestern Ethiopia

Abstract

Ethiopian Afromontane forests are rich in biodiversity and they a part of the eastern biodiversity hotspot. However, they are the most degraded ecosystems, continuously shrinking in size. Arbuscular mycorrhizal fungi (AMF) form a symbiotic association with land plants; thereby assist plants by absorbing nutrients and water beyond root depletion zones. Further they help plants in tolerating abiotic and biotic stresses. The objective of this study was to determine the AMF spore density and species diversity associated to the dominant plant species in Aradie and Zengena dry Afromontane forests. Transects were laid down in Aradie and Zengena dry Afromontane forests and 20 plots were selected from each forest. About 1 kg rhizosphere soil was collected from each plant species in December, January and February. AMF spore extraction was done by using wet sieving and decantation method. The mean AMF spore density was varied between 17.3 and 196 spores per 100 g dry soil in Aradie forest and it was between 84 and 234 spores per 100 g dry soil in Zengena forest. The highest AMF spore density was recorded from Olea africana (196 spores per 100 g dry soil) in Aradie forest and 234 spores per 100 g dry soil from Cupressus lucitanica in Zengena forest. Six AMF morphotypes belonging to three genera and 15 morphotypes belonging to four genera were recorded from Aradie and Zengena forests, respectively. Genus Acaulospora was dominantly recorded from 71.4% of plant species in Aradie forest and from 100% plants in Zengena forest. Plants Acacia abyssinica and Cupressus lucitanica harbored the highest AMF species. Hence, these plant species and AMF species associated to them can be used in the rehabilitation and restoration of dry Afromontane forests in Ethiopia.