Kelps usually form sori on their vegetative blades or sporophylls, and occasionally on stipes, with a notable exception being the primitive kelp Aureophycus aleuticus (Aureophycaceae), which forms sori on its discoid (haptera-free) holdfast. Here we reveal sorus formation on the holdfast (and blade and stipe) of the warm temperate annual kelp Ecklonia radicosa (Lessoniaceae), whose holdfast is formed by haptera, as is typical of the Laminariales. Surprisingly, hapteral sori continued to release zoospores until December, following blade loss in October. Such production of sori on holdfasts may be advantageous for surviving higher water temperatures and grazing pressure in warm temperate waters.
About the authors
Shingo Akita is a PhD candidate working with on a JSPS fellowship for young scientists at Tokyo University of Marine Science and Technology in Tokyo, Japan. He has studied ecology of Ecklonia radicosa during his Master’s course and genetic diversity of kelps. His research interests include ecology of kelps, herbivorous fish and deforestation.
Hirokazu Yamada is currently a researcher at the Suruga-Bay Deep Seawater Aquaculture Research Center of Shizuoka Prefectural Research Institute of Fishery in Shizuoka, Japan. His recent research is focused on restoration of seaweed beds in non-urchin barrens.
Madoka Ito is a group leader in the Fishery Management Division, Shizuoka Prefecture, Japan. His research interests include marine ecology and crustaceans.
Michael H. Graham is a Professor at Moss Landing Marine Laboratories. He is an experimental ecologist interested in the population biology of habitat-forming species, and the role that variability in the population dynamics and biogeography of these species plays in regulating the ecology and evolution of their associated communities. His research program currently focuses on seaweed-based systems (primarily kelps).
Daisuke Fujita is an Associate Professor at Tokyo University of Marine Science and Technology, Tokyo, Japan. He is a marine ecologist and phycologist and has worked on the ecology of deforestation and restoration of seaweed beds for more than 35 years. His recent research focuses on potential vegetation in urchin barrens.
The authors thank Akira Sasaki, Kunihiro Shirai and Naoki Iida for their assistance in SCUBA survey and colleagues in the laboratory for their advice during the sample treatments.
Akita, S. 2015. Survival strategy of Eckloniopsis radicosa inhabiting Diadema barren at Hirasawa, Numazu City, Sizuoka Prefecture. Tokyo University of Marine Science and Technology. Master thesis.Search in Google Scholar
Akita, S., H. Yamada, M. Ito and D. Fujita. 2014. Phenology of annual kelp Eckloniopsis (Phaeophyceae, Laminariales) forest on a Diadema barren in Uchiura Bay, Central Pacific Coast of Honshu, Japan. J. Appl. Phycol.26: 1141–1148.10.1007/s10811-013-0213-2Search in Google Scholar
Bartsch, I., C. Wiencke, K. Bischof, C.M. Buchholz, B.H. Buck, A. Eggert, P. Feuerpfeil, D. Hanelt, S. Jacobsen, R. Karez, U. Karsten, M. Molis, M.Y. Roleda, H. Schubert, R. Schumann, K. Valentin, F. Weinberger and J. Wiese. 2008. The genus Laminariasensu lato: recent insights and developments. Europ. J. Phycol.43: 1–86.10.1080/09670260701711376Search in Google Scholar
Bolton, J.J. 2010. The biogeography of kelps (Laminariales, Phaeophyceae): a global analysis with new insights from recent advances in molecular phylogenetics. Helgol. Mar. Res.64: 263–279.10.1007/s10152-010-0211-6Search in Google Scholar
Fairhead, V.A. and A.C. Cheshire. 2004. Rates of primary productivity and growth in Ecklonia radiata measured at different depths, over an annual cycle, at West Island, South Australia. Mar. Biol.145: 415–426.10.1007/s00227-004-1308-8Search in Google Scholar
Fujita, D. 2010. Current status and problems of Isoyake in Japan. Bull. Fish. Res. Agen.32: 33–42.Search in Google Scholar
Graham, M.H., J.A. Vásquez and A.H. Buschmann. 2007. Global ecology of the giant kelp Macrocystis: from ecotypes to ecosystems. Oceanogr. Mar. Biol. Annu. Rev. 45: 39–88.10.1201/9781420050943.ch2Search in Google Scholar
Hiatt, R.W. and D.W. Strasburg. 1960. Ecological relationship of the fish fauna on coral reefs of the Marshal Islands. Ecol. Monogr.30: 65–127.10.2307/1942181Search in Google Scholar
Kai, T., K. Nimura, H. Yasui and H. Mizuta. 2006. Regulation of sorus formation by auxin in Laminariales sporophytes. J. Appl. Phycol.18: 95–101.10.1007/s10811-005-9020-8Search in Google Scholar
Kawai, H., T. Hanyuda, L.M. Ridgway and K. Holser. 2013. Ancestral reproductive structure in the basal kelp Aureophycus aleuticus. Sci. Rep. 3: 1–7.10.1038/srep02491Search in Google Scholar PubMed PubMed Central
Kawashima, S. 1989. Illustrated book of Japanese kelp. 1st edition. North Japan Ocean Publication Center, Sapporo. pp. 156–157 (in Japanese).Search in Google Scholar
Kiriyama, T., M. Noda and A. Fujii. 2001. Grazing and bite marks on Ecklonia kurome, caused by several herbivorous fishes. Aquacul. Sci.49: 2–7 (in Japanese with English abstract).Search in Google Scholar
Kjellman, F.R. and J.V. Peterson. 1885. Om Japan’s Laminariaceer. Vega-exp. Vetensk. Iakttag.4: 263.Search in Google Scholar
Komazawa, I., T. Sugino, K. Takino, K. Ando and Y. Yokohama. 2006. Growth and maturation of the brown alga Eckloniopsis radicosa, on the coast of Izu-Oshima Island, central Japan. Aquacul. Sci.54: 489–494 (in Japanese with English abstract).Search in Google Scholar
Komazawa, I., Y. Sakanishi and J. Tanaka. 2015. Temperature requirements for growth and maturation of the warm temperate kelp Eckloniopsis radicosa (Laminariales, Phaeophyta). Phycological Res.63: 64–71.10.1111/pre.12068Search in Google Scholar
Kumura, T., H. Yasui and H. Mizuta. 2006. Nutrient requirement for zoospore formation in two Alariaceous plants Undaria pinnatifida (Harvey) Suringar and Alaria crassifolia Kjellman (Phaeophyceae: Laminariales). Fish. Sci.72: 860–869.10.1111/j.1444-2906.2006.01228.xSearch in Google Scholar
Leal, P.P., C.L. Hurd and M.Y. Roleda. 2014. Meiospores produced in sori of nonsporophyllous laminae of Macrocystis pyrifera (Laminariales, Phaeophyceae) may enhance reproductive output. J. Phycol. 50: 400–405.10.1111/jpy.12159Search in Google Scholar PubMed
Lee, R.E. 2008. Phycology. 4th edition. New York Cambridge University Pres, New York. pp. 448–464.10.1017/CBO9780511812897Search in Google Scholar
Lüning, K., A. Wagner and C. Buchholz. 2000. Evidence for inhibitors of sporangium formation in Laminaria digitata (Phaeophyceae) during the season of rapid growth. J. Phycol.36: 1129–1134.10.1046/j.1529-8817.2000.00017.xSearch in Google Scholar
Matsumura, W. and D. Fujita. 2002. Proposal of a self-sustainable abalone culture system water based on kelp intercalary growth in deep-sea water. Deep Ocean Water Res.3: 53–63 (in Japanese with English abstract).Search in Google Scholar
Ohmori, T. 1967. Morphogenetical studies on Laminariales. Biol. j. Okayama Univ. 13: 23–84.Search in Google Scholar
Okamura, K. 1927. Icones of Japanese Algae. Vol. 5, 8th edition. Kazamashobo, Tokyo. pp. 143–157.Search in Google Scholar
Rothman, M.D., L. Mattio, T. Wernberg, R.J. Anderson, S. Uwai, M.B. Mohring and J.J.J. Bolton. 2015. A molecular investigation of the genus Ecklonia (Phaeophyceae, Laminariales) with special focus on the southern hemisphere. J. Phycol. 51: 236–246.10.1111/jpy.12264Search in Google Scholar PubMed
Sanbonsuga, Y. and Y. Hasegawa. 1967. Studies on Laminariales in culture. I. On the formation of zoosporangia on the thalli of Undaria pinnnatifida and Costaria costata in culture. Bull. Hokkaido Reg. Fish. Res. Lab. 32: 41–48.Search in Google Scholar
Segawa, S. 1956. Colored illustrations of the seaweeds of Japan. 1st edition. Hoikusha, Osaka. pp. 44–45 (in Japanese).Search in Google Scholar
Sima, W. 2015. Ecology of benthic diatoms on Diadema barrens in Uchiura Bay, Shizuoka Prefecture. Tokyo University of Marine Science and Technology. Master thesis.Search in Google Scholar
Tsutsui, I. and M. Ohno. 1993. Growth and maturation of Undaria pinnatifida, U. undarioides and Eckloniopsis radicosa at Susaki Bay of Kochi in Japan. Aquacul. Sci.41: 55–60. (in Japanese with English abstract).Search in Google Scholar
Venegas, M., F.B. Tala and J.A. Vásquez. 1992. Sporangial sori on stipes of Lessonia nigrescens Bory (Laminariales Phaeophyta): a high frequency phenomenon in intertidal population of northern Chile. Bot. Mar. 35: 573–578.10.1515/botm.1922.214.171.1243Search in Google Scholar
Vergés, A., P.D. Steinberg, M.E. Hay, A.G. Poore, A.H. Campbell, E. Ballesteros, K.L. Heck Jr, D.J. Booth, M.A. Coleman, D.A. Feary, W. Figueira, T. Langlois, E.M. Marzinelli, T. Mizerek, P.J. Mumby, Y. Nakamura, M. Roughan, E. van Sebille, A.S. Gupta, D.A. Smale, F. Tomas, T. Wernberg and S.K. Wilson. 2014. The tropicalization of temperate marine ecosystems: climate-mediated changes in herbivory and community phase shifts. Proc. R. Soc. B281: 1–10.10.1098/rspb.2014.0846Search in Google Scholar PubMed PubMed Central
Yoshida T. 1998. Marine Algae of Japan. Uchida Roukakuho Publishing, Tokyo. pp. 344–347. (in Japanese).Search in Google Scholar
Yoshimura, T., T. Kiriyama and S. Kiyomoto. 2006. 3.1 The changing seaweed bed in western coast of Kyushu. In: (D. Fujita, M. Noda and H. Kuwahara, eds.) Marine Herbivorous Fish -Ecology, Fishery and Utilization-. Seizando-Shoten, Tokyo. pp. 33–50. (in Japanese).Search in Google Scholar
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