Responses of Chondrus crispus Stackhouse to different qualities of light: Morphological, physiological and molecular plasticity

This research highlights the morphological responses of Chondrus crispus Stackhouse to culture conditions associated with narrow spectrum blue light and narrow spectrum red light. Broad spectrum white light was used as the control in a seven-week light quality study. Parameters measured include relative growth rates, increase in widths and lengths of algal fragments, and tissue toughness. In a different two-week study, the effect of these light qualities on the photosynthetic efficiency of the alga was also measured. Pulse Amplitude Modulation (PAM) fluorometry was used to determine maximum quantum yield of algal tissue fragments grown in culture vessels exposed to each light quality treatment. In a third study, the functionality of the algal light harvesting components was explored in a stable green colour mutation arising from a clonal C. crispus population. Analysis and a comparison of the phycobilisome (PBS) pigment composition of the two colour phenotypes demonstrated genotypic adaptation in this alga at the cellular level.;In the first investigation, the blue grown fragments were significantly different from the red and the white grown fragments in at least one of the seven-day growth periods. Growth rate, fragment length and width were consistently lower in the blue grown samples, and tissue texture was softer. In the second study, photosynthetic efficiency expressed as maximum quantum yield was measured weekly. PAM fluorometer measurements demonstrated that at the end of week one, the blue grown algal fragments exhibited a higher quantum yield relative to the red or the white treatments. By the end of week two, however, there were no longer any significant differences between treatments.