Ja. Hemmingson et Rh. Furneaux, BIOSYNTHETIC ACTIVITY AND GALACTAN COMPOSITION IN DIFFERENT REGIONS OF THE THALLUS OF GRACILARIA-CHILENSIS BIRD, MCLACHLAN ET OLIVEIRA, Botanica marina, 40(4), 1997, pp. 351-357
Isotopic labelling with [C-13] and GC-MS analysis of the derived aldit
ol acetates have been used to detect and investigate galactan biosynth
esis in main branches and in four different regions along secondary br
anches of the thallus of the red alga Gracilaria chilensis Bird, McLac
hlan et Oliveira. Biosynthetic activity in terms of the proportion of
new galactan produced within these regions decreases with increasing b
ranch radius, i. e. with increasing distance from a branch tip, and is
lower still in main branches. Gas-liquid chromatographic analysis of
the alditol acetates of the constituent sugars of the galactan has sho
wn that tissue age has little effect on the proportions of L-galactopy
ranosyl-6-sulfate (i. e. precursor residues), or 6-O-methyl-D-galactop
yranosyl residues in the galactan of this species.