Communicating editor: U. Karsten.
Effect of irradiance and temperature on the photosynthesis of a cultivated red alga, Pyropia tenera (= Porphyra tenera), at the southern limit of distribution in Japan
Article first published online: 15 APR 2014
© 2014 Japanese Society of Phycology
Volume 62, Issue 3, pages 187–196, July 2014
How to Cite
Watanabe, Y., Nishihara, G. N., Tokunaga, S. and Terada, R. (2014), Effect of irradiance and temperature on the photosynthesis of a cultivated red alga, Pyropia tenera (= Porphyra tenera), at the southern limit of distribution in Japan. Phycological Research, 62: 187–196. doi: 10.1111/pre.12053
- Issue published online: 10 JUL 2014
- Article first published online: 15 APR 2014
- Manuscript Accepted: 9 JAN 2014
- Manuscript Received: 24 SEP 2013
- Japanese Ministry of Education, Culture, Sport and Technology (RT). Grant Numbers: #22510033, #25340012
- Special Coordination Funds for Promoting Science and Technology of Ministry of Education, Culture, Sport, Science and Technology (GNN)
- pulse amplitude modulation-chlorophyll fluorometry;
- temperature tolerance
The effect of irradiance and temperature on the photosynthesis of the red alga, Pyropia tenera, was determined for maricultured gametophytes and sporophytes collected from a region that is known as one of the southern limits of its distribution in Japan. Macroscopic gametophytes were examined using both pulse-amplitude modulated fluorometry and/or dissolved oxygen sensors. A model of the net photosynthesis–irradiance (P-E) relationship of the gametophytes at 12°C revealed that the net photosynthetic rate quickly increased at irradiances below the estimated saturation irradiance of 46 μmol photons m−2 s−1, and the compensation irradiance was 9 μmol photons m−2 s−1. Gross photosynthesis and dark respiration for the gametophytes were also determined over a range of temperatures (8–34°C), revealing that the gross photosynthetic rates of 46.3 μmol O2 mgchl-a−1 min−1 was highest at 9.3 (95% Bayesian credible interval (BCI): 2.3–14.5)°C, and the dark respiration rate increased at a rate of 0.93 μmol O2 mgchl-a−1 min−1°C−1. The measured dark respiration rates ranged from −0.06 μmol O2 mgchl-a−1 min−1 at 6°C to −25.2 μmol O2 mgchl-a−1 min−1 at 34°C. The highest value of the maximum quantum yield (Fv/Fm) for the gametophytes occurred at 22.4 (BCI: 21.5–23.3) °C and was 0.48 (BCI: 0.475–0.486), although those of the sporophyte occurred at 12.9 (BCI: 7.4–15.1) °C and was 0.52 (BCI: 0.506–0.544). This species may be considered well-adapted to the current range of seawater temperatures in this region. However, since the gametophytes have such a low temperature requirement, they are most likely close to their tolerable temperatures in the natural environment.