| Abstract: | Each of four clones from the Synura petersenii complex was grown at different pHs (5.5, 6.5, 7.5, 8.5) in batch culture experiments. Growth response curves and exponential growth rates were compared among clones and pH treatments in order to examine growth trend variation among the clonal groups. The clones were isolated from geographically distant North American localities. The clonal groups represented distinct mating types, an isolate and its subisolate, and S. petersenii- and S. glabra-like scale morphologies. No consistent relationship existed between growth response curve, and culture medium pH. Additionally, the trends across time differed according to clone and pH combination. Pairwise comparisons of linear trends from transformed growth response curves indicated two distinct clonal associations. Although the clonal associations corresponded with the final cell density of the cultures, growth response curves did not correspond with mating type, the parent-isolate and subisolate, or scale morphology. Clones with glabra-like scales had greater growth rates than the clone with petersenii-like scales. The conflicting results generated from growth response curve and growth rate analyses support the concept that S. petersenii and S. glabra form a highly variable, homogeneous grouping. |
