U. Karsten et al., C-13 AND H-1-NMR STUDIES ON DIGENEASIDE IN THE RED ALGA CALOGLOSSA-LEPRIEURII - A REEVALUATION OF ITS OSMOTIC SIGNIFICANCE, Plant physiology and biochemistry, 32(5), 1994, pp. 669-676
The main organic solutes potentially involved in the osmotic acclimati
on of the euryhaline red alga Caloglossa leprieurii (Ceramiales) were
analysed and spectroscopically characterised using natural abundance C
-13 and H-1 nuclear magnetic resonance (NMR) spectroscopy and gas-liqu
id chromatography/mass spectrometry (GLC/MS). In a marine and a freshw
ater isolate of C. leprieurii the polyhydric alcohol D-mannitol played
an important role as osmolyte. The heteroside digeneaside (alpha-D-ma
nnopyranosyl-(1-2)-glycerate) occurs in both populations, but its conc
entration remained low and almost unchanged with increasing external o
smotic pressures. In addition the quaternary ammonium compound trans-4
-hydroxyprolinebetaine was detected in marine isolates of C. leprieuri
i only. As with digeneaside the intracellular content remained low and
unaffected by salinity. While both metabolites are obviously not invo
lved in the osmotic acclimation of C. leprieurii, their possible funct
ion as compatible solutes is discussed.