Control by Light Quality of Chlorophyll Synthesis in the Brown Alga Desmarestia aculeata

Z. Naturforsch. 46c, 542-548 (1991); received February 13, 1991 Blue-Light Photoreceptor, Chlorophyll Synthesis, Desmarestia aculeata, Green-Light Photo­ receptor, Nitrate The chlorophyll synthesis in the brown algae Desmarestia aculeata is affected by light quali­ ty and by the nutrient state in the medium before the illumination. Pulses of 5 min of red, green and blue light together with 200 |iM nitrate in plants growing under natural conditions deter­ mined similar induction of chlorophyll synthesis. However, when the plants were incubated previously under starvation conditions the light effect was different. The induction of chloro­ phyll synthesis was greater after blue and green light than after red light pulses. Red-light pho­ toreceptor was only involved in the chlorophyll synthesis under no nutrient limitations and under starvation conditions after previous illumination with blue light followed by far-red light. The induction of chlorophyll synthesis by green and blue light pulses applied together with nitrate was greater when the algae were incubated in starvation conditions than in natural conditions (normal nutrient state). Because all light effects were partially reversed by far-red light the involvement of a phytochrome-like photoreceptor is proposed. In addition, a coaction between blueand a greenlight photoreceptors and phytochrome is suggested.