The response of myxogastrids to soil amendments

Myxogastrids (also referred to as myxomycetes or plasmodial slime moulds) are common to abundant organisms in soils, where they probably account for ~50% of the protozoan component represented by soil amoebae. In the present study, an effort was made to assess the possible effects of various soil amendments on myxogastrids, which exemplify the role of soil protozoans while also being relatively easy to quantify in soil samples. Amendments to soil in either field or microcosm experiments included the addition of water, glucose, a bacterial suspension and the herbicide Dalapon. Both trophic forms and encysted forms of myxogastrids were considered. As general observation, the responses of myxogastrids to the various amendments were distinct in the case of the herbicide, with the most obvious effect being the ratio of trophic to encysted forms. Any assessment of soil protozoans invariably will result in occasions where the population is grossly underestimated if samples are not tested after freezing as well as fresh. Frozen samples provide data on the total encysted population, which appears to “awakened” by the action of freezing.