The Adaptability Of Arbuscular Mycorrhizal Fungi To Different Soil Environmental Factors

The adaptability of four isolates of fungi to different pH, relative water contents of substrates, and different soil comprehensive fertility were studied.1.In the subsrtate humidity experiment, ,the host plant soybean(GJycine max (L. ) Merr.) inoculated with four AM fungi isolates (G.versiformel , G .versiforme2, G.mosseae, G.diaphanum) respectively was grown in sand at three relative water content (25% , 50% , 80%). The following results has been achieved: l)The root colonization and quantity of external hyphae that inoculated with isolate G.m in all three humidity treatments were higher than other isolates. Isolate G.m infacted root faster and was more stable in latter stage. The quantity of external hyphae was increased at latter stage 2) Isolate G.d grew better in the higher water content in former stage, while in latter stage,under three water treatments, the erexternal hyphae was not in high quantity although root colonization was high. 3) Isolates G.vl gained more external hyphae under lower water treatment in former stage with the lower root colonization, In latter stage, the root colonization and amount of external hyphae by Isolates G.vl were lower than that of G.m ; 4) Root colonization and quantity of external hyphae by G.vl, G.v2, G.d in latter stage were higher than in former stage. 5) In former and latter stages, all four isolates enhanced the phosphorus absorbtion, the water using efficient, and shoot weight of soybean. 6) Inoculating four AMF isolates could decrease soybean leaf water potential , leaf nature saturated wane, the proline contend wither coeffient,and enhance relative water content,and then alleviated the drought hardiness of soybean plant. 2. In the substrate fertility experiment, green pepper(Capsicum annum) inoculated with four AMF isolates (G.vl , G.v2, G.m , G.d) respectively was grown in soil with four comprehensive fertility treatments (Tl ., T2, T3, T4). The results are as follows:The root colonization by isolate G.m slightly decreased with the raising of fertility, but still was the highest among four isolates. The quantity of external hyphae was the highest under T2 treatment(soil available phosphorus 19.8mg/kg). Unlike isolate G.m, the root coloniztion andquantity of external hyphae of G.d decreased more with the raising of fertility. Under Tl treatment (soil available phosphorus 4.73mg/kg),the root coloniztion and quantity of external hyphae were the highest among four isolates. The root colonization and quantity of external hyphae of two isolates of G.v were lower than other two isolates. The peak of root coloniztion and quantity of external hyphae by G.vl were under T2 treatment; and the peak of root coloniztion by G.v2 was under T3 while the quantity of external hyphae decreased with the raising of fertility. Isolates.G.m and G.d had much wider fertility range ,but only G.m had best effection in enhancing top weitht,nitrogen, phosphorus , potassium(K) contents of sweet pepper.3. In the substrate pH experiment, maize(Zea mays 1) inoculated with four AM fungi isolates respectively was grown in pure sand of three pH treatment(pH6.0, pH7.5, pH 8.5). The results indicated: The root colonization by isolates G.m and G.d increased when substrate pH raised, and higher than other two isolates under three substrate pH treatment.The root colonization by isolates G.vl decreased when substrate pH raised, The root colonization by isolate G.v2 increased with the increasing of substrate pH in former stage, but are contrary in latter stage. The quantity of external hyphae of G.m was higher than other three isolates in two sampling stages, and was increased when substrate pH increased. The quantity of external hyphae of G.d was not greatly affected by variation of substrate pH in former stage, while increased with the increasing of substrate pH in latter stage. G.vl was resemble to G.d in former state,but is contrary in latter stage. The quantity of external hyphae of G.v2 was higher under substrate pH7.5. The mycorrhizal effects under different substrate pH by four A...