Institute of Environmental Biology, Utrecht University, Utrecht, the Netherlands.
Plant Signal Behav. 2010 Jun;5(6):655-62. doi: 10.4161/psb.5.6.11401. Epub 2010 Jun 1.
Plants growing in dense vegetations compete with their neighbors for resources such as water, nutrients and light. The competition for light has been particularly well studied, both for its fitness consequences as well as the adaptive behaviors that plants display to win the battle for light interception. Aboveground, plants detect their competitors through photosensory cues, notably the red:far-red light ratio (R:FR). The R:FR is a very reliable indicator of future competition as it decreases in a plant-specific manner though red light absorption for photosynthesis and is sensed with the phytochrome photoreceptors. In addition, also blue light depletion is perceived for neighbor detection. As a response to these light signals plants display a suite of phenotypic traits defined as the shade avoidance syndrome (SAS). The SAS helps to position the photosynthesizing leaves in the higher zones of a canopy where light conditions are more favorable. In this review we will discuss the physiological control mechanisms through which the photosensory signals are transduced into the adaptive phenotypic responses that make up the SAS. Using this mechanistic knowledge as a starting point, we will discuss how the SAS functions in the context of the complex multi-facetted environments that plants usually grow in.
生长在茂密植被中的植物会与其邻居争夺水、养分和光等资源。光竞争受到了特别深入的研究，不仅因为其对适应性行为的影响，还因为它对植物获得光截获的影响。在地上，植物通过光感觉线索来检测其竞争者，特别是红光：远红光比值（R:FR）。R:FR 是一个非常可靠的未来竞争指标，因为它会以植物特有的方式减少，这种减少是通过光合作用吸收红光来实现的，并且可以通过光敏色素感受器来感知。此外，还可以感知到蓝光的消耗，以用于检测邻居。作为对这些光信号的响应，植物会表现出一系列表型特征，这些特征被定义为避阴反应（SAS）。SAS 有助于将进行光合作用的叶片定位在树冠的较高区域，那里的光照条件更为有利。在这篇综述中，我们将讨论将光感觉信号转导为构成 SAS 的适应性表型响应的生理控制机制。我们将利用这种机制知识作为起点，讨论在植物通常生长的复杂多方面环境中，SAS 是如何发挥作用的。
