Polymorphism of selected marine Chaetophoraceae (Chlorophyta)

Abstract

The effect of variations in light-intensity and temperature on morphology, and the formation of setae as a function of nitrate and phosphate concentrations were determined for ten species of epiphytic, endozoic and epizoic marine Chaetophoraceae. Pronounced morphological plasticity, e.g. production of laxly branched or discoid thalli, occurred in the genera Ochlochaete and Ectochaete and branched, discoid or sarcinoid-like thalli in Pseudendoclonium. Bolbocoleon was not variable under a wide range of environmental conditions. Setae were always formed by two taxa, Bolbocoleon piliferum and Ectochaete ramulosa, but were never formed by Pseudendoclonium submarinum, Pseudulvella heterotricha, Pseudulvella prostrata or Entocladia testarum under variable nitrate and phosphate concentrations. In media deficient in nitrogen and phosphorus, algae that normally did not produce setae had long delicate bulbous setae, e.g. Entocladia viridis and Entocladia flustrae. The phenotypic plasticity of the marine Chaetophorac...