Characteristics of Pectic Polysaccharides from Rice Shoots

Pectic polysacchasides from the starch-free cell wall preparation of rice (Oryza sativa) shoots have been extracted in sequence with cyclohexane-trans-1,2-diaminetetra-acetate(CDTA)and Na2CO3. The total amount of polysaccharides extracted with the agents was estimated as approximately 1% of the cell walls. The extracted polysaccharides were fractionated by DEAE-Trisacryl M ion-exchange chromatography yielding five fractions, and the monosaccharide composition and molecular mass were constructed from homogalacturonan and rhamnogalacturoanan containing the "hairy" region with galactosyl and arabinosyl side-chains. The solubilized pectic polysaccharides after treatment with two pectolytic enzymes accounted for 0.4～0.6% of the starch-free cell walls.