ALIZARIN RED DYE AS A MARKER FOR MEASURING GROWTH IN<i>CORALLINA OFFICINALIS</i>L. (CORALLINACEAÈ, RHODOPHYTA)¹

Abstract

ABSTRACT The vital stain alizarin red was incorporated into the calcified walls of incipient medullary cells of Corallina officinalis L. while they were being produced in a terminal meristem. After about 5 h the stained tier of medullary cells formed a red‐purple band from which additional growth could be measured in the field and in non‐agitated cultures. Alizarin red was also taken up by epithallial cells and one month after staining, plants in the field lacked stained epithallia, whereas those in culture retained some of the stain. Possibly the lack of water motion in culture reduced the epithallial sloughing that occurs in nature. Growth rates measured by this technique were approximately 1.4 mm per month in the field and 1.2 mm per month in culture and were not affected by alizarin red.