Sexual compatibility in Gonium pectorale (Volvocales: Chlorophyceae) from soil of a single pond

Abstract

Clones of Gonium pectorale O.F.M. were crossed in all combinations at 20 °C and the resultant zygotes were examined to determine the degree of sexual compatibility within a single pond (dry soil sample originally). Two distinct groups were recognized within the 31 clones isolated and tested from a single sample, with all the clones in one group incompatible with those of the other. However, members of both groups were compatible with three additional clones. The existence of more than one group of sexually compatible clones isolated from a single soil sample indicates the fallacy of applying the term 'population' to such a sample, although geographically a small unit (<15 cm diam).