Brassinolide (BR), as a new type of plant hormones, is involved in the processes of plant growth and stress response. Previous studies have reported the roles of BR in regulating plant developmental processes and also response tolerance to abiotic stresses in plants. The main purpose of our study was to explore whether nitric oxide (NO) plays a role in the process of BR-induced adventitious root formation in cucumber (Cucumis sativus L.). Exogenous application of 1 μM BR significantly promoted adventitious rooting, while high concentrations of BR (2–8 μM) effectively inhibited adventitious rooting. NO donor (S-nitroso-N-acerylpenicillamine, SNAP) promoted the occurrence of adventitious roots. Simultaneously, BR and SNAP applied together significantly promoted adventitious rooting and the combined effect was superior to the application of BR or SNAP alone. Moreover, NO scavenger (c-PTIO) and inhibitors (L-NAME and Tungstate) inhibited the positive effects of BR on adventitious rooting. BR at 1 μM also increased endogenous NO content, NO synthase (NOS-like) and Nitrate reductase (NR) activities, while BRz (a specific BR biosynthesis inhibitor) decreased these effects. In addition, the relative expression level of NR was up-regulated by BR and SNAP, whereas BRz down-regulated it. The application of NO inhibitor (Tungstate) in BR also inhibited the up-regulation of NR. BR promoted the formation of adventitious roots by inducing the production of endogenous NO in cucumber.

中文翻译：

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一氧化氮参与油菜素内酯诱导的黄瓜不定根发育

油菜素内酯（BR）作为一种新型植物激素，参与植物生长和胁迫响应过程。先前的研究报道了BR在调节植物发育过程中的作用，以及对植物中非生物胁迫的响应耐受性。我们研究的主要目的是探讨一氧化氮（NO）是否在BR诱导黄瓜（Cucumis sativus L.）的不定根形成过程中起作用。外源施用1μMBR可显着促进不定根，而高浓度的BR（2-8μM）可有效抑制不定根。NO供体（S-亚硝基-N-乙酰青霉胺，SNAP）促进不定根的发生。同时，BR和SNAP一起使用可显着促进不定根生根，其综合效果优于单独使用BR或SNAP。而且，NO清除剂（c-PTIO）和抑制剂（L-NAME和钨酸盐）抑制BR对不定根生根的积极作用。1μM的BR也增加了内源性NO含量，NO合酶（类似NOS）和硝酸还原酶（NR）的活性，而BRz（一种特定的BR生物合成抑制剂）降低了这些作用。另外，NR和NRAP上调NR的相对表达水平，而BRz下调NRz的相对表达水平。NO抑制剂（钨酸盐）在BR中的应用也抑制了NR的上调。BR通过诱导黄瓜内源性NO的产生，促进了不定根的形成。NO清除剂（c-PTIO）和抑制剂（L-NAME和钨酸盐）抑制BR对不定根生根的积极作用。1μM的BR也增加了内源性NO含量，NO合酶（类似NOS）和硝酸还原酶（NR）的活性，而BRz（一种特定的BR生物合成抑制剂）降低了这些作用。此外，BR和SNAP上调了NR的相对表达水平，而BRz下调了NRz的相对表达水平。NO抑制剂（钨酸盐）在BR中的应用也抑制了NR的上调。BR通过诱导黄瓜内源性NO的产生，促进了不定根的形成。NO清除剂（c-PTIO）和抑制剂（L-NAME和钨酸盐）抑制BR对不定根生根的积极作用。1μM的BR也增加了内源性NO含量，NO合酶（类似NOS）和硝酸还原酶（NR）的活性，而BRz（一种特定的BR生物合成抑制剂）降低了这些作用。另外，NR和NRAP上调NR的相对表达水平，而BRz下调NRz的相对表达水平。NO抑制剂（钨酸盐）在BR中的应用也抑制了NR的上调。BR通过诱导黄瓜内源性NO的产生，促进了不定根的形成。另外，NR和NRAP上调NR的相对表达水平，而BRz下调NRz的相对表达水平。NO抑制剂（钨酸盐）在BR中的应用也抑制了NR的上调。BR通过诱导黄瓜内源性NO的产生，促进了不定根的形成。另外，NR和NRAP上调NR的相对表达水平，而BRz下调NRz的相对表达水平。NO抑制剂（钨酸盐）在BR中的应用也抑制了NR的上调。BR通过诱导黄瓜内源性NO的产生，促进了不定根的形成。