In situ measurements of cell wall components in the red alga Solieria chordalis (Solieriaceae, Rhodophyta) by FTIR microspectrometry

Cell wall composition of dried sections of Solieria chordalis have been studied in situ using FTIR microspectrometry. Infrared profiles were found to be similar to that of extracted iota-carrageenan. Cortex, sub-cortex and medulla were compared for their iota-carrageenan content through analysis of ratios between peak heights. Discrepancies in sulfate substitution on C2 and in the apparent proportion of 3,6-anhydrogalactose rings are discussed. An iota-carrageenase treatment on the tissues resulted in a drastic decrease in the sulfate content of the cell wall, as well as a partial elimination of 3,6-anhydrogalactose rings. These preliminary results suggest that FTIR microspectrometry is an accurate method for assessment of cell wall differentiation and also variations in sulfate substitutions on the cell wall polysaccharides of S. chordalis.