Sporulation of symbiotic arbuscular mycorrhizal fungi inside dead seeds ofa non-host plant

Abundant spores of arbuscular mycorrhizal fungi (AMF) were found in the cav ities of dead seeds of the non-host plant species Chenopodium album, one of the first colonizers of polluted soils on waste deposits from the pyrite s melter and of power station fly ash. The aim of this study was to verify th is phenomenon and to find out whether the cavity inside the seeds or the or ganic matter released from decomposing seeds is crucial for sporulation. Am endment of whole seeds into four polluted soils significantly increased spo rulation of native fungi, namely indigenous Glomus sp. BEG140, a cluster-fo rming isolate preferably sporulating within seed cavities. No effect of see d amendment was found for non-indigenous Glomus mosseae BEG25, suggesting a possible adaptation of sporulation strategy of the AMF isolate indigenous in polluted soils. Whereas soil amendment with whole seeds stimulated sporu lation many fold, as compared to soil without seeds, amendment with crushed seeds had no significant effect on sporulation; therefore increased sporul ation was probably caused by the presence of seed cavities rather than by o rganic matter. There was no significant effect of seed amendment on root co lonisation of lettuce as a host plant, however, seed amendment influenced t otal length of extraradical mycelium and its NADH-diaphorase activity. Biot est conducted with maize as a host plant grown in the soils from the experi ment showed no effect of previous seed amendment on inoculum viability.