Influence of blue light on the photosynthetic capacity of marine plants from different taxonomic, ecological and morphological groups

• Published in: European journal of phycology Vol. 29; no. 1; pp. 21 - 27
• Main Authors: Forster, R.M., Dring, M.J.
• Format: Journal Article
• Language: English
• Published: Cambridge Taylor & Francis Group 01.02.1994; New York, NY Cambridge University Press
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Autoecology; Biological and medical sciences; Blue light; Brown algae; Fundamental and applied biological sciences. Psychology; Littoral ecology; Marine; Morphology; Phaeophyta; Photosynthesis; Plants and fungi; Taxonomy; Algae; Biological evolution; Environmental factor; Ecophysiology; Carbon; Marine environment; Absorption; Light; Morphology; Habitat; Photosynthesis; Thallophyta
• ISSN: 0967-0262; 1469-4433
• DOI: 10.1080/09670269400650441

The photosynthetic rates of 47 species of marine plants (mainly seaweeds) have been measured in a saturating irradiance of red light before and after exposure to a 2 min pulse of blue light. In the majority of brown algae tested (20 out of 25 species) the pulse of blue light caused a rapid and significant increase in the rate of photosynthesis, often of over 100%, which decayed away over the following 1-3 h. However, apart from a small response in Codium, blue light did not affect the light-saturated photosynthesis in any species of green or red algae tested, or in a planktonic diatom (Phaeodactylum tricornutum) or a seagrass (Zostera noltii). This type of response to blue light is, therefore, common among species of brown macroalgae but appears to be absent from all other taxonomic groups of marine plants tested so far. Within the brown algae, the greatest response to blue light was recorded in species from the littoral zone, and little or no stimulation was observed in sublittoral species. Brown algae with a thin or filamentous morphology exhibited a higher degree of blue light stimulation than species with thicker thalli. The maximum photosynthetic rate in red light of thin, littoral species such as Petalonia fascia or Colpomenia peregrina could be transiently increased by over 200% after exposure to blue light at 50 μmol m -2 s -1 for 2 min. The size of this contribution to the photosynthetic performance of the plant suggests that blue wavelengths are essential for maximal productivity of these species in the natural environment. Members of the Fucaceae were the only littoral brown algae which showed little or no photosynthetic response to pulses of blue light. Previous work had indicated that the stimulatory effect of blue light was the result of an increase in the rate of transport of inorganic carbon from seawater to the chloroplast. The distribution of the response among the brown algae supports this hypothesis, since blue light stimulation was more prevalent in algae from habitats in which inorganic carbon frequently limits photosynthesis (e.g. high light and low water movement in the littoral environment) than in those from habitats where plant growth is primarily limited by the availability of light (e.g. the sublittoral zone).