Life history of Porphyra hollenbergii Dawson (Bangiales, Rhodophyta) from the Gulf of California, México

Abstract

López-Vivas J.M., Pacheco-Ruiz I., Riosmena-Rodríguez R. and Yarish C. 2011. Life history of Porphyra hollenbergi Dawson (Bangiales, Rhodophyta) from the Gulf of California, México. Phycologia 50: 520–529. DOI: 10.2216/10-58.1

The life history of Porphyra hollenbergii Dawson, a species endemic to the Gulf of California (Mexico), was investigated in relation to temperature, photoperiod and photon fluence rates. The hypothesis was that its life history is controlled by extremes of temperature (< 10°C to > 30°C), photoperiod (short/neutral/long) and photon fluence levels (low/high light). Culture experiments were set up using a factorial 5 × 5 × 3 design with five photon fluence levels (10, 20, 40, 60 and 80) µmol photons m⁻² s⁻¹), five temperatures (10, 15, 20, 25 and 30°C) and three photoperiods [8:16, 12:12 and 16:8 light:dark (L:D)]. For the gametophyte phase, the optimal release of zygotospores was at 15°C, with photon fluence level of 60 µmol photons m⁻² s⁻¹ and long photoperiod 16:8 L:D. Germination was best at 20°C, a photon fluence level of 60 µmol photons m⁻² s⁻¹ and under a long photoperiod 16:8 L:D. The abundance of archeospores differed significantly at temperatures of 25 and 30°C. The number of archeospores mm⁻² of the conchocelis tufts was significantly different in the long photoperiod 16:8 L:D when compared with the neutral 12:12 and short 8:16 L:D. The abundance of conchosporangia at temperatures of 15, 25 and 30°C were different and differed from the other conditions. In addition, abundance of conchosporangia mm⁻² were significantly different in all photoperiod treatments. Conchospores were released after 6 weeks at 10°C, 20 µmol photons m⁻² s⁻¹ at 8:16 L:D. On the basis of our results, we found that water temperatures were the limiting factor for conchocelis growth. However, it is the combination of photoperiod and high water temperatures that are the environmental conditions that appear to control the development of archeospores and conchospores. Porphyra hollenbergii life history is controlled by an array of factors at each stage, strongly suggesting the environmental influence of the habitat on this species.

Key Words::

• Archeospores
• Conchocelis
• Conchospores
• Endemic
• Environmental
• Reproduction

ACKNOWLEDGEMENTS

This study was supported by the Mexican Council for the Sciences and Technology (CONACYT-50173Q) that granted a PhD scholarship (CONACYT 157780) and the Autonomous University of Baja California (UABC-0572). We also thank all those who participated in the laboratory work, as well as Alberto Gálvez T. and Biology students at UABC and personnel from UABCS herbarium for their assistance during the fieldwork. We thank the support of the Connecticut Sea Grant College Program, the National Marine Aquaculture Initiative (National Oceanic and Atmospheric Administration, US Department of Commerce) and US Agency for International Development Training, Internships, Exchanges, and Scholarships program between the Universidad Autónoma de Baja California and the University of Connecticut (UABC-UCONN).