NITROGEN ALLOCATION AND STORAGE PATTERNS IN <i>GRACILARIA TIKVAHIAE</i> (RHODOPHYTA)¹

Abstract

ABSTRACT Internal nitrogen pools in thalli of Gracilaria tikvahiae McLachlan were examined in three experiments as a function of total nitrogen content of the thallus, nitrogen deprivation, and nitrogen resupply. Amino acids and proteins appeared to form the major nitrogen storage pools in G. tikvahiae , while DNA appeared to be relatively unimportant in this regard. Inorganic nitrogen in the forms of NH 4 + and NO 3 − was found in the thalli; however, its contribution to the total nitrogen, pools was small. Within the protein pool, the phycoerythrin pigments appear important as a source of nitrogen when thalli are initially becoming nitrogen limited. In general, there was an inverse relationship between the levels of nitrogen and the carbohydrate content of the algal thalli.