Extraction of arbuscular mycorrhizal fungus spores from clayey soil

Abstract

A n o p t i m a l s p o r e e x t r a c t i o n procedure is deduced for collecting spores of arbuscular mycorrhizal fungi (AMF spores) from clayey soil. The key to ef ficient spore collection is how to dif fuse gathered clayey particles, since significant numbers of spores are coated with clayey par ticles. A sucrose-centrifuge spore extraction method was used for AMF spore collection. The ef fect on collected spore numbers of the soil-suspension shaking time and the ultrasonic processing time was tested using a clayey soil taken from a natural tropical forest. The number of AMF spores increased gradually with shaking-time up to approximately 20 minutes, suggesting that the AMF spores were ef fectively released from clayey soil by shaking. Ultrasonic processing for longer than 30s reduced the extracted spore numbers. It is concluded that 40 minutes soil-suspension shaking-time and 30 seconds ultrasonic processing gives a suitable extraction procedure for collecting AMF spores for clayey soil. This extraction procedure for AMF spores from clayey soil is set out step by step in an Appendix.