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Title: The ecology of myxogastrids (myxomycetes).
Author: Feest, A.
ISNI:       0000 0001 3458 7610
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 1984
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1.Myxogastrids were shown to be common on bark of trees in the Bristol area and a variety of species were isolated. 2.Myxogastrids were more common on old bark than young bark. 3.Myxogastrids were isolated from banana peel but not from a variety of dung samples. 4.Myxogastrids were isolated from soil and a medium and method for their enumeration were developed.Soil was chosen as the habitat for further quantitative research. 5.The recor"ding unit for myxogastrids was the Plasmodium Forming Unit (P.F.U.). 6.Myxogastrids were found to be patchily distributed in soil and more abundant in the surface layers than from several centimetres deep. 7.A precise and repeatable sampling system was devised consisting of many small samples pooled to form a single large sample. Samples from nine sites were taken at monthly intervals for one year. These samples were assayed for myxogastrids by a standard proceedure. 8.The biological and edaphic parameters of the series of soil samples were also measured and weather records from the Long Ashton recording station collected. 9.A series of soil samples was taken from Sites of Special Scientific Interest in the Bristol area and assayed as for the temporal samples. IO.A number of soil samples were obtained from various countries and assayed for myxogastrids. 11.Myxogastrids were not abundant in typical woodland soils but they were in many other sites, even including a Barley field. 12.Graphical analysis of some of the biological parameters and of the soil moisture of the temporally sampled sites showed that there was a high negative correlation between soil bacterial numbers and P.F.U.'s in response to changes in soil moisture. 12.Populations of soil ciliates and amoebae showed a response to soil bacteria similar to that shown by the P.F.U.'s but not always synchronously. 13.Frost appeared to lead to increased numbers of myxogastrids in soil. l4.Statistical analysis of the the ecological data showed a high positive correlation between P.F.U.'s and pH and negative with organic matter. Numbers of P.F.U.'s were highly positively correlated with those of other soil protozoa which, with the exception of dictyostelids, all showed similar responses to soil physical properties • IS. The S.S.S.I. data analysis showed similar correlations to that of the temporal data but not as strongly. 16.The foreign samples showed myxogastrids to be widespread and not confined to normally moist soils for some were recovered from deserts. 17.Myxogastrids were amenable to experimental manipulations used to follow their population dynamics, and were shown to possess forms resistant to freezing. The latter appeared to stimulate excystment of dormant P.F.U.'s. 18.Microcosm experiments showed a pronounced rhizosphere effect, but a role for myxogastrids in the enhancement of nutrient cycling and uptake was not conclusively shown. 19.A series of samples from Czechoslovakia showed similar characteristics to samples from the Bristol area. 20.Most species of myxogastrids isolated from soils were of the genus Didymium but with the exception of Didymium squamulosum • I and D. difforme conclusive identification of most 1solates was not.possible. 21. Calculations suggest myxogastrids represent a significant biomass in some soils and that this biomass corresponds to a similarly significant biomass of bacterial prey.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Ecology