Endomycorrhizae in plant colonization on coastal sand-dunes at Cooloola, Queensland

Abstract

Soil, fungi, including species forming endomycorrhizae, appear to be important to pioneer plants colonizing coastal sand-dunes in the subtropics. In three mobile dunes at Cooloola, Queensland, networks of fungal hyphae were very common in the surface 0-20 cm of bare sand of the colonizing zones. These networks, consisting of long threads of hyphae, extend out into the bare sands from the roots of pioneer seedlings, most of which are endomycorrhizal. The fungi intermesh sand-grains to form aggregates which appear to be an important factor in stabilizing these loose sands. The sands are dominantly quartz grains partly covered by thin sesquioxide coatings which contain some phosphorus. Phosphorus held by sesquioxide is generally regarded as being unavailable to most plants. However, the close attachment of hyphae to these coatings, the lack of alternative sources of phosphorus and the prominence of endomycorrhizal fungi are consistent with these fungi obtaining phosphorus from these surfaces. These fungi appear to be important in plant colonization of these dunes and could have appliction in revegetaton of disturbed areas.