Mycorrhizal status of indigenous tree species in a forest biome of the Eastern Cape, South Africa

Abstract

Mycorrhizal fungi are intimately associated with plant roots, affecting plant growth, health and increasing the plants' tolerance to environmental stress. Several mycorrhizal types are recognized based primarily on morphological characteristics within plant roots. When considering propagation and management of an indigenous plant species, it is essential to know its mycorrhizal status. Root samples from 17 tree species common to the pockets of forest in the Eastern Cape province, and representing the families Rubiaceae, Scrophulariaceae, Oleaceae, Podocarpaceae, Myrsinaceae, Anacardiaceae, Caesalpinoideae, Papilionoideae, Rutaceae, Meliaceae, Celastraceae, Flacouticeae and Ebenaceae, were sampled and examined for mycorrhizal colonization. Microscopic examination of all the species produced evidence of morphological structures indicative of endomycorrhizal associations as indicated by the presence of intercellular hyphae combined with vesicles, arbuscules or hyphal coils. Hyphal coils (also known as Paris-type associations) appeared to be abundant, especially within the Cassine genus. Arbuscules (also known as Arum-type associations) were scarce but sometimes present, and vesicles were prolific in Olea capensis. Most of the tree species examined have been assigned arbuscular mycorrhizal status. No ectomycorrhizal associations were recorded.