CHANGES IN ESTERIFICATION OF THE URONIC-ACID GROUPS OF CELL-WALL POLYSACCHARIDES DURING ELONGATION OF MAIZE COLEOPTILES
CHANGES IN ESTERIFICATION OF THE URONIC-ACID GROUPS OF CELL-WALL POLYSACCHARIDES DURING ELONGATION OF MAIZE COLEOPTILES
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DOI：
10.1104/pp.98.2.646
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发表时间：
1992-02-01
期刊：
影响因子：
7.4
通讯作者：
CARPITA, NC
中科院分区：
文献类型：
--
作者：
KIM, JB;CARPITA, NC
禾本科植物的细胞壁含有两种主要的多糖，即半纤维素葡糖醛酸阿拉伯聚糖和富含半乳糖醛酸的果胶。 利用酯化糖醛酸羧基选择性还原生成6，6-二氘中性糖的技术，测定了玉米伸长过程中这两种糖醛酸的酯化程度和酯化变化。胚芽鞘 葡萄糖醛酸阿拉伯聚糖的葡萄糖醛酸在胚芽鞘伸长过程中的任何时候似乎都没有酯化。 胚胚芽鞘的半乳糖基糖醛酸约65%酯化，但这一比例增加到近80%，在快速伸长阶段，然后返回到约60%，在伸长结束。 未膨胀胚芽鞘细胞壁中的半乳糖醛酸甲酯约占总酯化量的三分之二。 甲基酯的比例在整个伸长过程中下降，并没有占酯化半乳糖醛酸单位的比例在增长过程中的增加。 结果表明，在细胞壁膨胀过程中，草果胶多糖的半乳糖醛酸单元可能转化为其它类型的酯或形成酯样化学作用。 新的酯或酯样相互作用的积累与含有半乳糖醛酸单元的聚合物与细胞壁的共价连接是一致的。
Cell walls of grasses have two major polysaccharides that contain uronic acids, the hemicellulosic glucuronoarabinoxylans and the galactosyluronic acid-rich pectins. A technique whereby esterified uronic acid carboxyl groups are reduced selectively to yield their respective 6,6-dideuterio neutral sugars was used to determine the extent of esterification and changes in esterification of these two uronic acids during elongation of maize (Zea mays L.) coleoptiles. The glucosyluronic acids of glucuronoarabinoxylans did not appear to be esterified at any time during coleoptile elongation. The galactosyluronic acids of embryonal coleoptiles were about 65% esterified, but this proportion increased to nearly 80% during the rapid elongation phase before returning to about 60% at the end of elongation. Methyl esters accounted for about two-thirds of the total esterified galacturonic acid in cell walls of unexpanded coleoptiles. The proportion of methyl esters decreased throughout elongation and did not account for the increase in the proportion of esterified galactosyluronic acid units during growth. The results indicate that the galactosyluronic acid units of grass pectic polysaccharides may be converted to other kinds of esters or form ester-like chemical interactions during expansion of the cell wall. Accumulation of novel esters or ester-like interactions is coincident with covalent attachment of polymers containing galactosyluronic acid units to the cell wall.