Taxonomy and Ecology Of Inland Sand Dune ... - Mycorrhizae

10irregular, reniform, fusiform, and clavatein spores occur in VAM fungi. Sporecolor can range from hyaline to white topale yellow, orange, red, brown, darkbrown, or black. The differences incolor can be due to pigmentation in thespore wall or in the spore content(Morton, 1988).Traditionally,morphologicalcharacteristics of the spore walls ofVAM fungi are used in speciesidentification (Mosse and Bowen, 1968;Gerdemann and Trappe, 1974; Trappe,1982). Spore wall characteristicsbecame the most importantmorphological characteristic afterWalker (1983) suggested usingstandardized terminology and wallmurographs. He originally proposedfour wall types, viz., the unit, laminated,evanescent, and membranous wall. Healso introduced the concept of a hyphalperidial wall. As new species weredescribed, new categories of spore wallswere added, i.e., the coriaceous wall byWalker (1986), the amorphous wall byMorton (1986), the expanding wall byBerch and Koske (1986), and thegerminal wall by Spain et al. (1989).b. SUBTENDING HYPHALMORPHOLOGYThe spores of most VAM fungi areproduced on one or more subtendinghyphae. Most Glomus species have asingle subtending hypha on their spore(Morton, 1988). Some species, such asG. glomerulatum Sieverding, G.halonatum Rose and Trappe, G.heterosporum Smith and Schenck, andG. lacteum Rose and Trappe producespores on 1-3 subtending hyphae. G.formosanum Wu and Chen and G.multisubtensum Mukerji, Bhattacharjeeand Tewari form spores on 1-4subtending hyphae. The color ofsubtending hyphae in most species ofGlomus, Sclerocystis, Gigaspora, andScutellospora is similar or lighter thanspore wall color. Subtending hyphalshapes range from straight, recurved,cylindrical, flared, funnel-shaped,constricted or irregular. The openingbetween the subtending hypha and thespore content may remain open or maybe closed by a plug, a septum, a spore-