School of Biological Sciences, University of Bristol, Bristol, BS8 1UG, UK.
Plant J. 2013 Mar;73(6):980-92. doi: 10.1111/tpj.12088. Epub 2012 Dec 31.
Plants detect the presence of neighbouring vegetation by monitoring changes in the ratio of red (R) to far-red (FR) wavelengths (R:FR) in ambient light. Reductions in R:FR are perceived by the phytochrome family of plant photoreceptors and initiate a suite of developmental responses termed the shade avoidance syndrome. These include increased elongation growth of stems and petioles, enabling plants to overtop competing vegetation. The majority of shade avoidance experiments are performed at standard laboratory growing temperatures (>20°C). In these conditions, elongation responses to low R:FR are often accompanied by reductions in leaf development and accumulation of plant biomass. Here we investigated shade avoidance responses at a cooler temperature (16°C). In these conditions, Arabidopsis thaliana displays considerable low R:FR-mediated increases in leaf area, with reduced low R:FR-mediated petiole elongation and leaf hyponasty responses. In Landsberg erecta, these strikingly different shade avoidance phenotypes are accompanied by increased leaf thickness, increased biomass and an altered metabolite profile. At 16°C, low R:FR treatment results in the accumulation of soluble sugars and metabolites associated with cold acclimation. Analyses of natural genetic variation in shade avoidance responses at 16°C have revealed a regulatory role for the receptor-like kinase ERECTA.
植物通过监测环境光中红光 (R) 与远红光 (FR) 波长比值 (R:FR) 的变化来检测邻近植被的存在。植物光受体中的光敏色素家族感知到 R:FR 的减少，并引发一系列被称为避荫回避综合征的发育反应。这些反应包括茎和叶柄的伸长生长增加，使植物能够超越竞争植被。大多数避荫回避实验都是在标准实验室生长温度 (>20°C) 下进行的。在这些条件下，低 R:FR 诱导的伸长反应通常伴随着叶片发育减少和植物生物量积累减少。在这里，我们在较冷的温度 (16°C) 下研究了避荫回避反应。在这些条件下，拟南芥显示出相当大的低 R:FR 介导的叶面积增加，而低 R:FR 介导的叶柄伸长和叶片下弯反应减少。在 Landsberg erecta 中，这些截然不同的避荫回避表型伴随着叶片厚度增加、生物量增加和代谢物谱的改变。在 16°C 下，低 R:FR 处理导致可溶性糖和与冷驯化相关的代谢物的积累。在 16°C 下对避荫回避反应的自然遗传变异进行分析表明，受体样激酶 ERECTA 发挥了调节作用。
