Sasaki K, Taylor I E
Department of Botany, University of British Columbia, 3529-6270 University Blvd., Vancouver, British Columbia, V6T 2B1, Canada.
Plant Physiol. 1986 Jun;81(2):493-6. doi: 10.1104/pp.81.2.493.
Radiolabeled d-[1-(3)H]glucose was fed by imbibition under sterile conditions to bean (Phaseolus vulgaris L.) seeds. After 72 and 96 hours of feeding, the (3)H was located in uronic acid and pentose residues as well as hexose residues of cell wall polysaccharides in growing hypocotyl and root. Free myo-inositol present in cotyledons, hypocotyl, and root also contained (3)H, showing that de novo synthesis of myo-inositol from [1-(3)H]glucose did occur during the first 72 hours of germination. More than 90% of the labeled, free myo-inositol was present in the cotyledons. The (3)H percentage in trifluoroacetic acid-soluble arabinose residues of cell wall polysaccharides from 72-hour-old bean hypocotyls was only half of their mole percentage. On the other hand, (3)H percentages in hexose residues were higher than their mole percentages. The results suggest that myo-inositol is synthesized from reserve sugars during the very early stages of germination, and that the newly synthesized myo-inositol, as well as that stored in cotyledons, can be used for the construction of new hypocotyl and root cell wall polysaccharides after conversion into uronic acids and pentoses via the myo-inositol oxidation pathway.
在无菌条件下，通过浸吸法将放射性标记的d-[1-(³H)]葡萄糖供给菜豆（Phaseolus vulgaris L.）种子。供给72小时和96小时后，³H存在于正在生长的下胚轴和根中细胞壁多糖的糖醛酸、戊糖残基以及己糖残基中。子叶、下胚轴和根中存在的游离肌醇也含有³H，这表明在萌发的最初72小时内确实发生了由[1-(³H)]葡萄糖从头合成肌醇的过程。超过90%的标记游离肌醇存在于子叶中。72小时龄菜豆下胚轴细胞壁多糖中三氟乙酸可溶性阿拉伯糖残基的³H百分比仅为其摩尔百分比的一半。另一方面，己糖残基中的³H百分比高于其摩尔百分比。结果表明，肌醇是在萌发的早期阶段由储备糖合成的，并且新合成的肌醇以及储存在子叶中的肌醇，在通过肌醇氧化途径转化为糖醛酸和戊糖后，可用于构建新的下胚轴和根细胞壁多糖。
