Changes in cell wall polysaccharides of each part of ethylene-treated mungbean sprout during the growth [Japanese]

摘要

Studies on cell wall polysaccharides in ethylene treated mungbean sprout have mainly been focused on the hypocotyls at early growth stage. In this paper, the quantitative changes in cell wall polysaccharides of each part (hypocotyl, cotyledon, root and seed coat) of commercially produced mungbean sprouts were investigated and evaluated the characteristics of cell wall biosynthesis in each part. Although fresh weight of both hypocotyl and root increased as the plants grew in darkness, the growth of hypocotyl was far bigger than that of root. Total uronic acid concentration in pectic substances increased in both hypocotyl and root within 3 days after ethylene treatment, while it increased thereafter in cotyledon. In hypocotyl, uronic acid concentration increased rapidly in water- and HCl-soluble fractions between the days 3 and 5, while neutral sugar concentration retained a low level or rather decreased. In root, a rapid increase in uronic acid concentration was detected in both EDTA- and HCl-soluble fractions, while neutral sugar concentration retained a low level during the experiment, irrespective of pectin sub-fractions. These results suggest that, when mungbean sprouts grew, the activity of the biosynthesis of main chain of water- and HCl-soluble pectin polymers were higher than other fractions in hypocotyl, while the activity of the biosynthesis of main chain of EDTA- and HCl-soluble pectin polymers were higher than other fractions in root.