Exogenous hydrogen peroxide reversibly inhibits root gravitropism and induces horizontal curvature of primary root during grass pea germination
Exogenous hydrogen peroxide reversibly inhibits root gravitropism and induces horizontal curvature of primary root during grass pea germination
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外源过氧化氢可逆性抑制草豌豆萌发过程中根系向地性并诱导初生根水平弯曲
DOI：
10.1016/j.plaphy.2012.01.017
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发表时间：
2012-04-01
影响因子：
6.5
通讯作者：
Wang, Chongying
中科院分区：
文献类型：
--
作者：
Jiang, Jinglong;Su, Miao;Wang, Chongying
在水平放置的培养皿上，在蒸馏水(dH(2O)O)中萌发过程中，由于向灰色性，草豆L的初生根垂直于培养皿底部生长。然而，当在外源过氧化氢(H_2O_2)中萌发时，初级根平行于培养皿底部并不对称地生长，形成水平弯曲。时间-过程实验表明，在初生根出现之前喷施过氧化氢的效果最强。萌发后施加过氧化氢不能诱导根弯曲。剂量研究表明，随着H_2O_2浓度的增加，初生根弯曲频率显著增加。这种曲度可以被过氧化氢的清除剂二甲基硫脲(DMTU)直接抵消，但不能被过氧化氢产生的抑制剂二苯基碘(DPI)和吡啶所抵消。外源H_2O_2处理提高了过氧化氢清除酶[包括抗坏血酸过氧化物酶(APX：EC 1.11.1.11)、过氧化氢酶(CAT：EC 1.11.1.6)和过氧化物酶(POD：EC 1.11.1.7)]的活性，降低了内源H_2O_2水平和根系活力。虽然豌豆种子在萌发过程中吸收了外源H_2O_2，但石蜡切片DAB染色表明，外源H_2O_2只进入根的表皮，而不进入内部组织。这些数据表明，在幼苗胚根萌发过程中，外源H_2O_2处理会导致根部向重反应的可逆性丧失和初级根的水平弯曲。(C)2012年爱思唯尔·马森公司。版权所有。
During germination in distilled water (dH(2)O) on a horizontally positioned Petri dish, emerging primary roots of grass pea (Lathyrus sativus L) grew perpendicular to the bottom of the Petri dish, due to grayitropism. However, when germinated in exogenous hydrogen peroxide (H2O2), the primary roots grew parallel to the bottom of the Petri dish and asymmetrically, forming a horizontal curvature. Time-course experiments showed that the effect was strongest when H2O2 was applied prior to the emergence of the primary root. H2O2 failed to induce root curvature when applied post-germination. Dosage studies revealed that the frequency of primary root curvature was significantly enhanced with increased H2O2 concentrations. This curvature could be directly counteracted by dimethylthiourea (DMTU), a scavenger of H2O2, but not by diphenylene iodonium (DPI) and pyridine, inhibitors of H2O2 production. Exogenous H2O2 treatment caused both an increase in the activities of H2O2-scavenging enzymes [including ascorbate peroxidase (APX: EC 1.11.1.11), catalase (CAT: EC 1.11.1.6) and peroxidase (POD: EC 1.11.1.7)] and a reduction in endogenous H2O2 levels and root vitality. Although grass pea seeds absorbed exogenous H2O2 during seed germination, DAB staining of paraffin sections revealed that exogenous H2O2 only entered the root epidermis and not inner tissues. These data indicated that exogenously applied H2O2 could lead to a reversible loss of the root gravitropic response and a horizontal curvature in primary roots during radicle emergence of the seedling. (C) 2012 Elsevier Masson SAS. All rights reserved.