Photoperiodic history affects the critical daylength of the short-day plant Acrosymphyton purpuriferum (Rhodophyta) |
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Authors: | Anneke M Breeman |
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Institution: | Department of Marine Biology, Biological Centre , University of Groningen , PO Box 14, NL 9750, AA Haren (GN), The Netherlands |
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Abstract: | The crustose tetrasporophyte of the red alga Acrosymphyton purpuriferum is a qualitative short-day plant in the formation of its tetrasporangia. The critical daylength for the response was determined in plants precultured in various long-day regimes 20:4, 18:6, 16:8 and 14:10 (L:D, h)]. There was a strong influence of photoperiodic history. The sharper the decrease in daylength the stronger and faster the plants responded. The critical daylength (daylength inducing 50% response) increased from 9·5 h for plants precultured in 14 h days to 12·5 h for plants precultured in 20 h days. Acrosymphyton thus responds to a change in daylength, rather than to a fixed critical value. This is of adaptive significance in synchronising the onset of reproduction throughout its broad depth range in the subtidal region. |
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Keywords: | Acrosymphyton purpuriferum critical daylength photoperiodism photoperiodic history red alga short-day response |
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