GELRITE AND AGAR DIFFERENTLY INFLUENCE CYTOKININ-SENSITIVITY OF A MOSS

Physcomitrella patens wild-type as well as its cytokinin-sensitive differentiation mutant PC22 exhibit premature as well as enhanced bud formation when grown on basal medium gelled with Gelrite compared to plants grown on basal medium gelled with agar. Thus, cultivation on Gelrite mimics cytokinin-treatment of mosses. However, plants could only respond to exogenous cytokinin when grown on agar-media but were inhibited by the growth regulator when grown on Gelrite. These effects could not be mimiced by the addition of inorganic salts, nor by the addition of glucose or rhamnose to agar-gelled basal media.