An Analytical Study on Starch-degrading Enzymes and Composion of Carbohydrates in the Endosperm during Germination of Barley Seeds

  • KIRIBUCHI Shigeo
    Department of Agricultural Chemistry, Faculty of Agriculture, The University of Tokyo
  • NAKAMURA Michinori
    Department of Agricultural Chemistry, Faculty of Agriculture, The University of Tokyo

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Other Title
  • 大麦の発芽に伴うデンプン分解酵素活性および炭水化物含量の変動
  • オオムギ ノ ハツガ ニ トモナウ デンプン ブンカイ コウソ カッセイ オヨビ タンスイカブツ ガンリョウ ノ ヘンドウ オオムギ ノ ハツガ ニ カンスル ケンキュウ 1

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Description

In order to clarify the mechanism of breakdown of reserve starch in the endosperm of germinating barley seeds, analyses of carbohydrates and activities of starch-degrading enzymes were carried out during the course of germination.<br> 1) α-Amylase activity was found after about 2 days of seed imbibition, and the starch in the endosperm was degraded rapidly in a close parallel to the developmental pattern of α-amylase activity and disappeared from the endosperm starting from areas in contact with the scutellum.<br> 2) β-Amylase activity, already present in the endosperm of ungerminated seeds, increased immediately after seed imbibition. The starch in the endosperm was little degraded by β-amylase during the first 2 days of germination until the α-amylase activity appeared in the seed endosperm.<br> 3) Phosphorylase activity could not be detected in the extracts of seed endosperm during the germination, but there existed a starch-degrading enzyme activity that required inorganic phosphate.<br> 4) There was a transient decline in the content of soluble sugars during the first 2 days of seed germination, followed by the gradual increase which coincided with the degradation of starch. Among the soluble sugars, sucrose content was the highest in seed endosperm during germination, while free fructose content was very small. The content of glucose, although not present in ungerminated seed endosperm, was gradually increased after about 2 days of seed imbibition and did not decline appreciably even at very later stages.<br> 5) The significance of these analytical results was discussed in terms of the physiology of germinating barley seeds.

Journal

  • Nippon Nōgeikagaku Kaishi

    Nippon Nōgeikagaku Kaishi 47 (5), 333-340, 1973

    Japan Society for Bioscience, Biotechnology, and Agrochemistry

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