Organs such as hypocotyls and petioles rapidly elongate in response to shade and temperature cues, contributing to adaptive responses that improve plant fitness. Growth plasticity in these organs is achieved through a complex network of molecular signals. Besides conveying information from the environment, this signaling network also transduces internal signals, such as those associated with the circadian clock. A number of studies performed in Arabidopsis hypocotyls, and to a lesser degree in petioles, have been informative for understanding the signaling networks that regulate elongation of aerial plant organs. In particular, substantial progress has been made towards understanding the molecular mechanisms that regulate responses to light, the circadian clock, and temperature. Signals derived from these three stimuli converge on the BAP module, a set of three different types of transcription factors that interdependently promote gene transcription and growth. Additional key positive regulators of growth that are also affected by environmental cues include the CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) and SUPPRESSOR OF PHYA‐105 (SPA) E3 ubiquitin ligase proteins. In this review we summarize the key signaling pathways that regulate the growth of hypocotyls and petioles, focusing specifically on molecular mechanisms important for transducing signals derived from light, the circadian clock, and temperature. While it is clear that similarities abound between the signaling networks at play in these two organs, there are also important differences between the mechanisms regulating growth in hypocotyls and petioles.

中文翻译：

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调节空中植物器官伸长的分子途径：重点是光，昼夜节律和温度

诸如下胚轴和叶柄的器官响应于阴影和温度提示而迅速伸长，有助于改善植物适应性的适应性反应。这些器官的生长可塑性是通过复杂的分子信号网络来实现的。除了从环境中传递信息之外，该信令网络还转换内部信号，例如与生物钟相关的信号。在拟南芥下胚轴中进行的许多研究以及在叶柄中进行的程度较小的研究，对于了解调节空中植物器官伸长的信号网络都是有益的。特别地，在理解调节对光，生物钟和温度的响应的分子机制方面已经取得了实质性的进展。从这三种刺激产生的信号会聚在BAP模块上，一组相互依赖地促进基因转录和生长的三种不同类型的转录因子。其他关键的正向生长调节剂也受环境提示的影响，包括组成性光生性蛋白1（COP1）和PHYA-105（SPA）E3泛素连接酶抑制蛋白。在这篇综述中，我们总结了调节下胚轴和叶柄生长的关键信号通路，特别关注了重要的分子机制，这些机制对转导源自光，昼夜节律和温度的信号非常重要。尽管显然在这两个器官中起作用的信号网络之间存在很多相似之处，但调节下胚轴和叶柄生长的机制之间也存在重要差异。