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

52spores do not occur in this new species.G. botryoids spores have a wallthickness of 20.00 µm and their sizerange is 145.00 to 250.00 µm ( Rothwell& Victor, 1984). Yet, in this newspecies the spore wall thickness is up to35.84 µm and both the minimum andmaximum spores’ size (128.00- X -192.00 µm) less than that given from G.botryoids.In G. tenebrosum and G. etunicatesspores are yellow to very dark brown inthe former, and yellow to brown in thelatter; and spores size is (200.00-)240.00 (-270.00) X (205.00-) 230.00 (-270.00) µm in the former and 68.00 X144.00 µm in the latter ( Berch & Fortin,1983; and Becker & Gerdemann, 1977).Young spores of Glomus sp are similarto spores of these two species, but themature spores are black; and theirspore’s size range is larger than G.etunicates and smaller than G.tenebrosum.Spores of Glomus sp can easily beidentified according to their size, color,wall, and subtending hyphal features.Spore wall groups, thickness, and poreopening size are more easily determinedif black spores are treated with 100%Clorox (100% Sodium hypochloritesolution) for 10 minutes.C. EFFECTS OF SOIL DEPTH,MOISTURE, AND pH. ON VAMCOLONIZATIONCompetition for a limited resource is oneof the strongest selective pressuresoperative in native plant communities(St. John and Coleman, 1983; Read,1991). My data compare a singlespecies (O. hymenoides) growing inthree levels of competitive constraint: 1.in competition with other species in thevegetated community, 2. underpresumably less competition in thesemivegetated community, and 3.without competition from other speciesin the pioneer community. There is asignificant increase in the ability of soilto support mycorrhizal colonizationwhen O. hymenoides grows in