Publication Date


Document Type


First Advisor

Mathers, G.K.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences




Plasmodia of the myxomycete Physarum gyrosum Rost, were placed under re­duced air pressures of 520; 350 and 180 mm. of mercury, simulating air pressure condi­tions found at 10,000; 20,000 and 35,000 feet altitude respectively. Data on fruit­ing time and morphological characteristics of the fruiting bodies were recorded. There was not a statistically significant difference in fruiting time between the experimental and the control plasmodia. A gradation of atypical characteristics of the fruiting bodies paralleled the ab­normal air pressure conditions under which the fructifications were formed. All of the fruiting bodies formed under an air pressure of 520 mm. of Hg showed no noticeable difference from the controls. Three of the 28 fruiting bodies formed at 350 mm. of Hg also showed no difference, however seven of the group possessed a herder and thicker peridium. The remaining 18 fructifications formed at 350 mm. of Hg and all 10 formed at 180 mm. of Hg showed extreme differences which included: the lack of a definite peridium and capillitium, the fruiting bodies were hard and brittle through­out, the 'twisted tubes" appearance of the fructification was suppressed, lime deposits on the surface were extensive, iridescence was lacking, and the spores were thin- walled and varied considerably in size and shape. Since the plasmodia were not grown in pure culture, it is difficult to determine if the morphological differences were caused directly by the reduced air pressure or in­directly through an effect on the microorganisms growing in association with the plas­modia.


Includes bibliographical references (leaf 14)


[iii], 24 pages




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