Physiological response of red macroalgae <italic>Pyropia yezoensis</italic> (Bangiales, Rhodophyta) to light quality: a short-term adaptation

Abstract

Light quality is a common environmental factor which influences the metabolism of biochemical substances in algae and leads to the response of algal growth and development. <i>Pyropia yezoensis</i> is a kind of economic macroalgae that naturally grows in the intertidal zone where the light environment changes dramatically. In the present study, <i>P. yezoensis</i> thalli were treated under white light (control) and monochromatic lights with primary colors (blue, green, and red) for 14 days to explore their physiological response to light quality. During the first 3 days of treatment, <i>P. yezoensis</i> grew faster under blue light than other light qualities. In the next 11 days, it showed better adaptation to green light, with higher growth rate and photosynthetic capacity (reflected by a higher rETRmax = 61.58 and Ek = 237.78). A higher non-photochemical quenching was observed in the treatment of red light than others for 14 days. Furthermore, the response of <i>P. yezoensis</i> to light quality also results in the difference of photosynthetic pigment contents. The monochromatic light could reduce the synthesis of all pigments, but the reduction degree was different, which may relate to the spectral absorption characteristics of pigments. It was speculated that <i>P. yezoensis</i> adapted to a specific or changing light environments by regulating the synthesis of pigments to achieve the best use of light energy in photosynthesis and premium growth and metabolism.