Semester

Fall

Date of Graduation

1999

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Horticulture

Committee Chair

Alan Sexstone.

Abstract

BIOLOGRTM GN and GP microtitre plates were used to compare functional diversity of large (>0.45 mum, LC) and small (<0.45 mum, SC) cells within A and B horizons of cultivated and forested Guernsey silt-loam soil without enrichment and following enrichment in dilution culture. Without enrichment, SC exhibited limited substrate utilization compared with LC. B horizon SC failed to positively utilize any carbon substrates, which suggests that they may be physiologically inactive and/or metabolically distinct from those in A horizon soils. Following enrichment, A horizon SC from highly diluted enrichment cultures produced substrate utilization patterns distinct both from all enrichments of LC and from SC obtained in less dilute enrichments. At any given inoculum dilution, A horizon SC exhibited greater substrate utilization than B horizon SC, which exhibited positive substrate utilization following enrichment. Amplified ribosomal DNA (ARDRA) analyses of SC dilution culture enrichments demonstrated distinct bacterial sub-populations from a single soil sample.

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