Involvement of nitric oxide in water stress-induced responses of cucumber roots
Involvement of nitric oxide in water stress-induced responses of cucumber roots
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DOI：
10.1016/j.plantsci.2009.09.007
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发表时间：
2009-12-01
期刊：
影响因子：
5.2
通讯作者：
Kubis, J.
中科院分区：
文献类型：
--
作者：
Arasimowicz-Jelonek, M.;Floryszak-Wieczorek, J.;Kubis, J.
研究了水分亏缺对黄瓜（Cucumis sativus cv.）一氧化氮（NO）生成的影响。利用no选择性荧光剂二氨基荧光素-2-二醋酸酯（DAF-2DA）的生物成像技术观察幼苗根系。轻度（5和10 h）水分亏缺的根系，根尖细胞和周围伸长区NO合成略有增加。然而，严重的（17 h）应力导致集中的NO生产主要集中在延伸区及以上。水胁迫诱导的NO生成被特异性NO清除剂2-（4-羧基苯基）-4,4,5,5-四甲基咪唑啉-1-氧-3-氧化物（cPTIO）和硝酸还原酶（NR）阻断，部分被一氧化氮合酶（nos样）抑制剂阻断。采用药理学方法验证了NO诱导黄瓜根系对水分亏缺的适应性反应的能力。NO供体（SNP 100 mu M和GSNO 100 mu M）预处理与植物水化状态（以相对含水量（RWC）衡量）呈正相关。在应激初期（5 h）， NO引起脂氧合酶（LOX）活性周期性升高，与脂质过氧化增强的时间依赖性相关。从10 h到严重胁迫（17 h），外源性NO能够降低LOX活性，减轻水亏诱导的膜通透性和脂质过氧化，通过原位组织化学染色测量TBARS含量。通过NO观察到的变化伴随着脯氨酸水平的显著降低，这表明这种渗透物的积累可能不是水分胁迫耐受所必需的。这些结果清楚地表明，NO的增加可能有助于植物在组织脱水的初始阶段触发有效的机制，减轻黄瓜幼苗根系严重的水分亏缺效应。2009爱思唯尔爱尔兰有限公司版权所有。
The effect of water deficit on nitric oxide (NO) generation was investigated in cucumber (Cucumis sativus cv. Dar) seedling roots using bio-imaging with an NO-selective fluorophor, diaminofluorescein-2-diacetate (DAF-2DA). Roots subjected to mild (5 and 10 h) water deficit showed slightly enhanced NO synthesis in cells of root tips and in the surrounding elongation zone. However, severe (17 h) stress resulted in an intensive NO production localized mainly in and above the elongation zone. Water stress-induced NO generation was blocked by a specific NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) as well as nitrate reductase (NR) and partially by nitric oxide synthase (NOS-like) inhibitors.A pharmacological approach was used in order to verify the capacity of NO to induce adaptive responses of cucumber roots to water deficit. A positive correlation was found between NO donor (SNP 100 mu M and GSNO 100 mu M) pretreatment and plant hydration status, measured as relative water content (RWC) during progressive dehydration. At an early stage (5 h) of stress duration NO caused a periodical increase in lipoxygenase (LOX) activity, correlated with time-dependent enhancement of lipid peroxidation. Beginning from 10 h up to severe stress (17 h) exogenous NO was able to diminish LOX activity and alleviate water deficit-induced membrane permeability and lipid peroxidation, measured as TBARS content and visualised by histochemical staining in situ. Observed changes via NO were accompanied by a significant reduction of proline level, suggesting that the accumulation of this osmolyte might not be essential in water stress tolerance. Obtained results clearly indicate that NO augmentation is likely to help the plant at the initial stage of tissue dehydration to trigger efficient mechanisms, mitigating severe water deficit effects in roots of cucumber seedlings. (C) 2009 Elsevier Ireland Ltd. All rights reserved.