Plants depend on gravity to provide the constant landmark for downward root growth and upward shoot growth. The phytohormone auxin and its cell‐to‐cell transport machinery are central determinants ensuring gravitropic growth. Statolith sedimentation toward gravity is sensed in specialized cells. This positional cue is translated into the polar distribution of PIN auxin efflux carriers at the plasma membrane, leading to asymmetric auxin distribution and consequently, differential growth and organ bending. While we have started to understand the general principles of how primary organs execute gravitropism, we currently lack basic understanding of how lateral plant organs can defy gravitropic responses. Here we briefly review the establishment of the oblique gravitropic set point angle in lateral roots and particularly discuss the emerging role of asymmetric cytokinin signaling as a central anti‐gravitropic signal. Differential cytokinin signaling is co‐opted in gravitropic lateral and hydrotropic primary roots to counterbalance gravitropic root growth.

中文翻译：

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不对称细胞分裂素信号传导反对根中的向地性。

植物依靠重力为向下的根生长和向上的枝条生长提供恒定的标志。植物激素生长素及其细胞间运输机制是确保向地生长的核心决定因素。在专门的细胞中感知到重力沉降。这种位置提示被转化为质膜上 PIN 生长素流出载体的极性分布，导致生长素分布不对称，从而导致生长差异和器官弯曲。虽然我们已经开始了解初级器官如何执行向地引力的一般原则，但我们目前缺乏对侧向植物器官如何对抗向地力反应的基本了解。在这里，我们简要回顾了侧根中倾斜重力设定点角度的建立，并特别讨论了不对称细胞分裂素信号作为中枢抗重力信号的新兴作用。在向地侧和向水性初生根中选择了差异细胞分裂素信号，以平衡向地性根的生长。