In this year there is the 40th anniversary of the first publication of plant nitric oxide (NO) emission by Lowell Klepper. In the decades since then numerous milestone discoveries have revealed that NO is a multifunctional molecule in plant cells regulating both plant development and stress responses. Apropos of the anniversary, these authors aim to review and discuss the developments of past concepts in plant NO research related to NO metabolism, NO signaling, NO's action in plant growth and in stress responses and NO's interactions with other reactive compounds. Despite the long-lasting research efforts and the accumulating experimental evidences numerous questions are still needed to be answered, thus future challenges and research directions have also been drawn up.

中文翻译：

---

四十年的历程：一氧化氮在植物中的产生和作用。

今年是Lowell Klepper首次发布植物一氧化氮（NO）排放40周年。从那以后的几十年中，许多里程碑式的发现揭示了NO是调节植物发育和胁迫响应的植物细胞中的多功能分子。在周年纪念日之后，这些作者旨在回顾和讨论植物NO研究中与NO代谢，NO信号传导，NO在植物生长中的作用以及胁迫响应以及NO与其他反应性化合物的相互作用有关的过去概念的发展。尽管进行了长期的研究工作并且积累了实验证据，但仍然需要回答许多问题，因此，也提出了未来的挑战和研究方向。