DARK FIXATION OF C14O2 BY OBLIGATE AND FACULTATIVE SALT MARSH HALOPHYTES

After dark fixation of C14O2 by salt marsh obligate halophytes, most of the 80% ethanol-soluble label appeared in the amino acid fraction. Species tested were Batis maritima L., Salicornia europaea L., Salicornia virginica L., and Borrichia frutescens (L.) D.C.A time study was made of the dark fixation products of C14O2 by Spartina alterniflora Loisel, a facultative halophyte, cultured with and without NaCl in the nutrient medium. In this species the greater proportion of label was recovered from amino acids (principally aspartic and glutamic acids) at times of 1 hour and less, the pattern changing to favor organic acids at longer times, mainly malic acid in NaCl-free plants. The shift to organic acids was slower in plus NaCl plants with aconitic and an unidentified acid appearing along with malic as the principal labelled acids.NaCl reduced the rate of C14O2 assimilation by Spartina alterniflora. Initially, the fixation pattern resembled that of obligate halophytes, becoming more like that of terrestial plants (glycophytes) after 1 hour.