XYLOSE-RICH POLYSACCHARIDES FROM THE PRIMARY WALLS OF EMBRYOGENIC-CELL LINE OF PINUS-CARIBAEA

Embryogenic cell lines of Pinus caribaea were isolated from somatic em bryogenesis from zygotic embryos. Previous studies showed that the pro teins and glycoproteins were characteristic of the embryogenic state. In the present work we were seeking typical feature in the polysacchar ide from the cell walls of embryogenic calli at nine days of culture. Sequential extraction with water, ammonium oxalate, dimethyl sulfoxide , sodium borohydride and 4.3 M potassium hydroxide revealed that the e xtracted polysaccharides contained high proportions of arabinose and s ignificant amounts of xylose. Fractionation of the hydrosoluble polyme rs on DEAE cellulose afforded a xylose-rich fraction (80% xylose, 24% glucose and lower properties of fucose and mannose). Methylation analy sis and C-13-NMR spectra showed that the glycan backbone consisted of beta 1-->4 linked xylosyl residues Similar study of the fractions extr acted respectively with DMSO and 4.3 M KOH showed the presence of poly disperse glycoxylans but excluded the presence of xyloglucan in signif icant amount. This could be a characteristic feature of embryogenic ce lls walls of Pinus caribaea or could be typical of cells grown as call uses. In the various fractions obtained from DEAE cellulose chromatogr aphy of the alkaline extract the infrequent occurrence of fucoxylans b eside an arabinogalactan showed again the unusual nature of the cell w all polymers of this embryogenic lines, which seems to differ greatly from those found in the primary wall of cells from suspension cultures . (C) 1997 Elsevier Science B.V.