Fig. 3. Linear discriminant analysis based on fatty acid profiles of desmid strains belonging to the time-isolation group. (a) Discrimination of the clusters ("very old", "old" and "new") at the start of cultivation (2 days). (b) Discrimination of the clusters at the end of cultivation (24 days). DF1 – the first discrimination function 1; DF2 – the second discrimination function; red triangles – strains cultivated> 35 years ("very old"); green quadrangles – strains cultivated between 15 and 35 years ("old"); blue circles – strains cultivated ≤ 15 years ("new"). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)