Effects Of Plant Species Diversity On Colonization Of AMF Under Different Conditions

The ecological functions of arbuscular mycorrhizal fungi (AMF) in natural and agroecosystem was greatly concerned in recent decades. AMF plays a very important roles in nutrients absorption, ecological restoration of heavy metal polluted soil. Despite of lots of reports of influence of AMF on plant community succession and ecological restoration of lead (Pb) polluted soil, the relationship of plant species diversity and their AMF community under on different soil conditions and their potential application in the restoration of the Pb containminated soil was kept poorly known. Studies on the effects of plant species and their coexisting on their AMF community and its colonization under various soil environments by means of filed cultivation, pot culture and controlled sand culture were conducted during 2001-2003. Main results obtained were shown as follows. l.Comparison of colonization of AMF of different plants lead polluted soilsThe AMF colonization of 14 mono-cultivated weed species in Pb added soil ( 334.525 Img/kgsoil) were investigated by pot experiments in growth chamber. The results showed that Pb in soil at the concentration (334.5251mg/kgsoil) did not affect on the biomass of weed plants significantly. But the colonization and sporulation of AMF in soil were significantly affected by Pb-pollution. AMF infection rates of Poa amata, LaSiaapenme, Avenafatua, Vida cmcca, TrfoSvm repew decreased greatly in Pb-polluted soil, while that of Plantqp argmca, Gnopba&tm affine, Oxatis cornculata showed a significant increase. The AMF colonization of Vennda didyma showed less response to Pb-pollution. Mycorrhizal spores in most rhizospheric soil of weed species, except Vida cracca, TrfoHum npens and Oxalis cornculata, decreased significantly. 2 Influence of coexisting of various plant species on AMF colonization in Pb polluted soilComparing with monoculture,the results showed mat diversity did not affect on die AMFcolonization of weed plants (planted in soil at the concentration (334.5251mg/kgsoil) or nonpolluted soil)significandy.In the experiment of species combination with Trfolium repens, Lolium perenne, Poa annua, Plan tago virginica, the infection rate of all species increased in Pb treatment except Poa annua, implying that diversified plant species coexistence may alleviate theimpacts of Pb on mycorrhizal colonization.3 Influence of plant species coexisting on AMF colonization in root system under field conditionsThe field experiment showed that the influence of species coexisting community on the AMF colonization in these plant root system significantly depended upon the plant species character. Increased complexity did not always promote the colonization of AMF in me root of all tested species. Comparing the infection rate of Kummtroma striata under monoculture condition, the AMF colonization both in two-species coexisting of (Digitaria dHaris + Kumtneroivia striata) and (Kummeronxa striata + Ixeris denticulate) showed no significant change. But the AMF colonization rate Kiaameroma striata in three-species coexisting of Digtaria ciUaris + Kummerowia striata + Ixeris dentiatlata was significant higher than that in monoculture. As to Ixeris denticulate, the AMF colonization rate in its root in two-species coexisting (Kuramcroiaa striata + Ixeris denticulate, Dig'taria dMaris + Ixeris denticulatd) and three-species coexisting (Dig'taria dSaris + Kumaterottta striata + Ixeris dentiatlata) were significandy higher than mat in monoculture condition. The colonization of AMF in Digtaria ciUaris showed no significant influence by the species diversity of plant community. All roots showed approximately the same AMF colonization rate under monoculture, two-species coexisting and three-species community.In over-wintering species experiment, AMF colonization showed significant difference, which was greatiy dependent upon the plant species character. The AMF colonization rate and index of LaHumperenne in all community in which GnapbaHum affim existed showed better colonization than that in Latium perenne mono...