Scenedesmus acutus Meyen was cultured at four temperatures (9.5 degrees, 16.5 degrees, 24 degrees, and 29 degrees C) in standard medium or in medium with filtered water from a Daphnia culture, Growth was significantly reduced at low temperatures. At 9.5 degrees C it took more than a week before formation of eight-celled coenobia occurred in both the absence and presence of water from a Daphnia culture, At higher temperatures, formation of four- and eight-celled coenobia occurred more rapidly and was already observed in the presence of Daphnia water within 2 days, As cultures aged, also in the absence of Daphnia water, four-celled coenobia became dominant. At cold temperature, cell volume initially was significantly larger but declined after 3-4 weeks. Grazer-induced colony formation had occurred independent of the incubation temperature, but the number of cells per colony was increased with declining temperature. The morphological expression may be interpreted as a cyclomorphosis driven by nutrients, temperature, and chemical cues from gazers. [KEYWORDS: colony formation; cyclomorphosis; Daphnia; ecomorph; growth; infochemicals; phenotypic plasticity; Scenedesmus acutus; temperature Phenotypic plasticity; morphological-changes; daphnia-pulex; phytoplankton; growth; cyclomorphosis; light; transformation; infochemicals; consequences]
Original languageEnglish
JournalJournal of Phycology
Journal publication date1999

ID: 231915