CHANGE OF WATER-SOLUBLE ARABINOGALACTAN-PROTEINS OF CABBAGE ACCOMPANYING ITS GROWTH .5. WATER-SOLUBLE GLYCOCONJUGATES OF VEGETABLES

Changes in water-soluble arabinogalactan-proteins (AGPs) in cabbages at five stages (I, seedlings with cotyledon; II, young seedlings with five to six leaves; III, initiation of head formation; IV, completion of head formation; V, flower stalk development) during the course of development were investigated. The results indicate that only the white head portion contained the higher molecular weight AGP (A-I) together with the lower molecular weight AGP (A-II) with the largest at stage IV. On the other hand, green leaves contained only A-II and its content decreased rapidly with progress of growth from stage I to stage IV. The chemical composition analyses also showed that the hydroxyproline content decreased significantly with growth. Based on these results, we concluded that cabbage leaves contained water-soluble AGPs throughout the growth of cabbage and AGP A-I was specific for head formation of cabbage.