The effects of inoculum forms (single-spore, multi-spores, or colonized root pieces) and host plants (Nicotiana tabacum L., Sorghum sudanense (Piper) Stapf, and Trifolium repens L.) on the development and inoculum potential (IP) of the arbuscular mycorrhizal fungi (AMF) :Glo-mus macrocarpum Tul & Tul, donuis mosseae (Nicol & Gerd.) Gerdemann & Trappe, Glomus ver-siforme (Karsten) Berch, and Sclerocystis sinu/osa Gerdemann & Bakhi cultured in pots were investigated. The lag phase of treatment with 50 spores or 0.5 g (fresh weight) of colonized root pieces was 4 weeks, much shorter than that of the treatment with 1 spore (8 weeks); the value of IP (VIP) and percentage of root colonization (PRC) of the former were greater than those of the latter. Only on the early stages of colonization was there difference between the 50 spores and the 0.5 g (fresh weight) of colonized root piece inoculation treatments. The EP per plant inoculated with 0.5 g (fresh weight) of colonized root pieces of AMF was greater than that of the other two treatments except G. versiforme on Nicotiana tabacum, while the PRC of the plants inoculated with 50 spores and 0.5 g (fresh weight) of colonized root pieces of AMF was higher than that of the 1 spore inoculation after 10 weeks. Trie VIP of AMF on Trifolium repens was significantly higher than that on the other two hosts. The VIP of G. mosseae, G. versiforme, and S. sinuosa was respectively greater than that of G. macrocarpum. This suggested that different species of AMF produced different VIP of the inoculum . Nicotiana tabacum was much better than the other host plants which used to be inoculated with single spore, and to produce inocula of AMF.
Resources and ecological distribution of Arbuscular mycorrhizal fungi(AMF) on wild plants in Shandong vegetation region were investigated during 1995-1997. A total of 182 rhizospheric soil samples were collected from 50 wild plants. Spores of AMF occurred in all samples. More than fourty species of AMF were isolated and 35 species in five genera were identified. Among the five genera,the frenquency of occurence was Glomus (51.7%)> Scutellospora (23.1)> Gigaspora(14.1%)>Acaulospora(9.5%)>Entrophospora (0.8%). Glomus mosseae, Gigaspora margarita are prominent species, G.versiforme, G.constrictum, S.gilmorei are common species to be isolated. The spore density of AMF was different: Gigaspora>Glomus>Scutellospora>Acaulospora>Entrophospora . The occurence and distribution of AMF are related to regional difference, soil factors(contents of N, P; organic matter and pH) and host plant.The prominent species in eastern part were Gi.margarita, G.mosseae and G.versiforme , while in middle and western part of Shandong province was G.mosseae . The occurence frequency of Glomus, Gigaspora and Scutellospora was much higher than that of other genera in eastern and middle part of Shandong province. While Glomus and Acaulospora were higher in the western part. The spore number of Gigaspora and Scutellospora were much more than that of other genera in the samples collected in the eastern and middle area, while Glomus and Acaulospora are more frequently encountered in the western part of Shandong provence.
