Is autosporulation a feature ofNannochloris?

摘要

The green algal genusNannochlorisNaumann was originally described as having a simple binary division mechanism and lacking autosporulation and a parental cell wall. An initial observation of autosporulation in one isolate ascribed to this genus encouraged a broader investigation to determine whether or not autosporulation is restricted to only certain forms or is the reproductive mechanism used in the genus as a whole. Five cultures were examined; all had typically chlorophycean ultrastructure and both chlorophyllsaandb. Nannochloris atomusdiffered from the other forms (twoNannochlorisspp.,Nannochloris bacillaris, andNannochloris maculants) in having a pyrenoid and different wall structure and other ultrastructural features. However, reproduction in all five was by autosporulation with a thin, yet clearly defined, parental wall surrounding the twondash;four daughter cells in electron micrographs. These and related findings of other workers point to the need for a redefinition of the genus.