THE CRYPTIC-GROWTH RESPONSE OF MAIZE COLEOPTILES AND ITS RELATIONSHIP TO H2O2-DEPENDENT CELL-WALL STIFFENING
THE CRYPTIC-GROWTH RESPONSE OF MAIZE COLEOPTILES AND ITS RELATIONSHIP TO H2O2-DEPENDENT CELL-WALL STIFFENING
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DOI：
10.1111/j.1399-3054.1995.tb00959.x
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发表时间：
1995-07-01
影响因子：
6.4
通讯作者：
SCHOPFER, P
中科院分区：
文献类型：
--
作者：
HOHL, M;GREINER, H;SCHOPFER, P
生长素介导的玉米（Zea mays L.）膨压降低0.45MPa，胚芽鞘节段消失。在这些条件下，冻融后测量的不可逆片段长度（l（irr））在8 h内稳定增加，但体内长度（l（tot））保持恒定。这种现象被称为“隐蔽生长”，是细胞壁硬化过程的一个标志，这似乎是细胞壁不可逆延伸的内在组成部分。使用一系列的代谢抑制剂，它表明，隐蔽的增长是由温度敏感的生化过程中的细胞壁，依赖于O-2和活性过氧化物酶的存在下，但不是ATP和蛋白质的合成。厌氧条件下的隐蔽生长的抑制可以通过外部H2 O2来缓解。此外，抗氧化剂抗坏血酸可以部分抑制隐蔽生长。它的结论是隐蔽的增长代表了壁硬化反应介导的过氧化物酶催化，过氧化氢依赖性交联的酚残基的壁聚合物。在快速生长的器官中的壁硬化反应的实验证明支持这样的概念，即不可逆的细胞伸长（生长）是由两种化学流变反应的相互作用引起的，所述两种化学流变反应是turgor-dependent壁松弛反应和单独的壁硬化反应，所述壁硬化反应通过氧化交联固定粘弹性延伸的壁结构，从而赋予壁延伸不可逆性。
Auxin-mediated elongation growth of maize (Zea mays L.) coleoptile segments can be nullified by lowering the turgor pressure by 0.45 MPa. Under these conditions irreversible segment length (l(irr)) measured after freezing/thawing increases steadily over a period of 8 h although the in vivo length (l(tot)) remains constant. This phenomenon, designated as 'cryptic growth', is an indication of a wall-stiffening process which appears to be an intrinsic component of irreversible cell wall extension. Using a range of metabolic inhibitors it is demonstrated that cryptic growth is caused by a temperature-sensitive biochemical process in the cell wall which, depends on the presence of O-2 and active peroxidase, but not on ATP and protein synthesis. Inhibition of cryptic growth by anaerobic conditions can be alleviated by external H2O2. Moreover, cryptic growth can be partially inhibited by the antioxidant ascorbate. It is concluded that cryptic growth represents a wall-stiffening reaction mediated by peroxidase-catalyzed, H2O2-dependent cross-linking of phenolic residues of wall polymers. The experimental demonstration of a wall-stiffening reaction in a rapidly growing organ supports the concept that irreversible cell elongation (growth) is caused by an interplay of two chemorheological reactions, a turgor-dependent wall-loosening reaction and a separate wall-stiffening reaction which fixes the viscoelastically extended wall structure through oxidative cross-linking and thus conferring irreversibility to wall extension.