INTRODUCTION

Mycorrhiza is the mutualistic symbiosis (non-pathogenic

ASSOCIATION) between soil-borne fungi with the roots of

higher plants (Sieverding, 1991). Two types of

mycorrhiza are known today: ecto- and endomycorrhizas.

The ectomycorrhizas are characterized by an

extracellular fungal growth in the ROOT cortex. They are

more common in temperate and boreal forest trees and

number over 5000 species mainly within the

Basidiomycetes (Siverding, 1991). Some tropical trees

such as pine and eucalyptus plants, however, have also

been found to form ectomycorrhizal associations. The

endomycorrhizas are characterized by inter-and

intracellular fungal growth in root cortex, forming specific

fungal structures, referred to as vesicles and arbuscles.

This characteristic growth gives the endomycorrhiza the

alternate name, vesicular arbuscular mycorrhiza. It is the

most widely distributed association in plants. About 80%

of all terrestrial plant species form this type of symboisis

(Smith and Read, 1997) and 95% of the world’s present

species of vascular plants belong to FAMILIES that are

charcteristically mycorrhizal (Quilambo, 2000).