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

11wall thickening or spore inner wall.Width and length measurement of thesubtending hyphae are used in speciesidentification.c. SPOROCARP MORPHOLOGYSporocarps are formed in peridial andpossibly in glebal hyphae of Sclerocystisand in some species of Glomus(Gerdemann and Trappe, 1974).Sporocarps are not known inEntrophospora, Gigaspora, andScutellospora (Ames and Schneider,1979; Berch, 1985; Walker and Sanders,1986). Sporocarps typically are absentin Acaulospora. The exceptions are A.myriocarpa Spain, Sieverding andSchenck, in which spores are in a cluster(Schenck et al., 1986), and A.sporocarpa Berch which has anaggregation of spores in a network ofhyphae (Berch, 1985). Externalsporocarp colorranges from white to brown. However,internal sporocarp color ranges fromwhite to black in Glomus and brown inSclerocystis species. Sporocarp shape isirregular in Glomus, but it is globose,subglobose or ellipsoid in Sclerocystisspecies (Morton, 1988). Two terms areused to describe hyphal arrangement insporocarps: the term peridium is usedwhen the hyphae form a loosely ortightly interwoven network on thesurface of the sporocarp, and the termglebal is used when the hyphae form amatrix in the sporocarp. Epigeoussporocarps can be large and brightlycolored. Hypogeous sporocarps aresmall and can be blend with soil textureand color. Sporocarps of diameters lessthan 1 mm can be separated by wetsieving and centrifugation (Powell andBagyaraj, 1984).2. SPORE DISPERSALAll VAM fungi depend on passivemeans of spore dispersal. Wind andanimals are good vectors for sporedispersal (Friese, 1984; MacMahon andWarner, 1984). In arid ecosystems,wind might be the most importantdispersal agent for VAM inoculum(Trappe, 1981; MacMahon and Warner,1984; Warner et al., 1987). However,animals are the major vectors for VAMinoculum in mesic habitats (Marx, 1975;