Received 11 October 1993. Accepted 1 February 1994.
ECOTYPIC VARIATION IN PHYLLOPHORA PSEUDOCERANOIDES (RHODOPHYTA) ENSURES WINTER REPRODUCTION THROUGHOUT ITS GEOGRAPHIC RANGE1
Article first published online: 19 OCT 2004
Journal of Phycology
Volume 30, Issue 3, pages 392–402, June 1994
How to Cite
Molenaar, F. J. and Breeman, A. M. (1994), ECOTYPIC VARIATION IN PHYLLOPHORA PSEUDOCERANOIDES (RHODOPHYTA) ENSURES WINTER REPRODUCTION THROUGHOUT ITS GEOGRAPHIC RANGE. Journal of Phycology, 30: 392–402. doi: 10.1111/j.0022-3646.1994.00392.x
We thank Drs. J. Cabioch, J. Hansen, C. A. Maggs, and A. Peters for collecting the isolates and Dr. I. Novaczek for establishing unialgal cultures. Technical assistance by Ms. T. E. Linders and Ms. E. M. Nijsing-Amptmeijer is acknowledged. Mr. E. Leeuwinga prepared the figures for publication. We are very grateful to the staff and technicians of the Biologische Anstalt Helgoland and the Station Biologique d Roscoff for their hospitality and for providing working facilities. F. J. M. especially thanks Dr. W. H. C. F. Kooistra, Dr. J. Cabioch, Dr. P. Leukart, Mr. H. Reichenberger, Mr. J. Begeman, and the local diving teams for assistance and cooperation. We also wish to thank Prof. C. van den Hoek for critical comments on the manuscript. The first author was supported by grants from the Royal Netherlands Academy of Sciences (K.N.A.W. Committee for Marine Biological Stations, seven travel grants for Helgoland and seven for Roscoff), by the French National Centre for Scientific Research (C.N.R.S.), the Netherlands Organization for Scientific Research (N.W.O.) (two travel grants for Roscoff), and the “Groninger Universiteits Fonds” (travel grant to Mr. J. Begeman).
- Issue published online: 19 OCT 2004
- Article first published online: 19 OCT 2004
- life history regulation;
- Phyllophora pseudoceranoides;
- temperature/daylength responses
Responses to temperature and daylength were determined in laboratory culture for isolates of the red alga Phyllophora pseudoceranoides (Gmelin) Newroth et A.R.A. Taylor from Nova Scotia, Iceland, Roscoff (France), and Helgoland (Germany). All isolates grew from 3° to 25° C and survived from -2° or 0° C to 27° C but not 30° C. Reproductive requirements differed between life history phases and isolates. Isolates from Helgoland and Roscoff formed sporangial sori at 3°-20° C, tetraspores at 3°-12° C, and procarps at 10°-20° C, irrespective of daylength. Spermatangia developed at 10°-23° C but only in long days. As the other European isolates, the isolate from Iceland formed tetrasporangia at 3°-12° C, but it had an additional requirement for short days. The Nova Scotian isolate formed sori at 10°-20° C and sporulated at 10°-18° C. When grown plants were transferred from noninductive to inductive conditions, sori were formed after 4 months and tetraspores developed and were shed (1-)3 months later. Procarps formed 1(-3) months after transfer.
The phenology of P. pseudoceranoides was studied at Helgoland and Roscoff, where similar seasonal patterns were observed. Plants were perennial, forming new blades from October to June, which degenerated between August and February. In June, reproductive structures (sori, spermatangia, and procarps) started to appear on the new blades. From October to April, mature cystocarps were found. Mature tetrasporangia were observed only in February.
The life history of P. pseudoceranoides is regulated by temperature and daylength. Differential effects on the different life history phases all serve to confine the production of spores (both carpospores and tetraspores) to the winter season. Differences in response between isolates from different geographic regions bring about the same effect: spores are shed only in winter.
The nature of the geographic boundaries of P. pseudoceranoides is discussed.