Department of Biological Sciences, College of Science, University of North Texas, 1155 Union Circle #305220, Denton, TX 76203-5017, USA.
Departamento de Ciencias Agrarias y del Medio Natural, Universitat Jaume I, Campus Riu Sec, Castello de la Plana E-12071, Spain.
Sci Signal. 2018 Feb 20;11(518):eaam9514. doi: 10.1126/scisignal.aam9514.
The plant canopy functions as an aerial array of light-harvesting antennas. To achieve maximal yield, each leaf within this array and the array as a whole need to rapidly adjust to naturally occurring fluctuations in light intensity and quality. Excessive light stress triggers the closing of pores in leaves called stomata to minimize moisture loss. We found that different leaves within the canopy of an plant, including leaves not directly exposed to light, coordinated stomatal closure in response to light stress by sending and receiving rapid systemic signals. This response required the plant hormones abscisic acid and jasmonic acid and was mediated by a rapid autopropagating wave of reactive oxygen species (ROS) production. Furthermore, this response depended on the function of genes encoding the ROS-generating NADPH oxidase RBOHD and various stomatal regulators, such as the anion channel SLAC1, GHR1 (guard cell hydrogen peroxide resistant 1), and lipoxygenase 1 (LOX1). Our findings reveal that plants function as highly dynamic and coordinated organisms, optimizing the overall response of their canopies to fluctuating light intensities.
植物冠层起到光捕获天线的空中阵列的作用。为了达到最大产量，该阵列中的每个叶片以及整个阵列都需要快速适应自然发生的光强和质量波动。过量的光应激会触发叶片中气孔的关闭，以最大程度地减少水分流失。我们发现，植物冠层内的不同叶片，包括未直接暴露在光线下的叶片，通过发送和接收快速系统信号来协调对光应激的气孔关闭。这种反应需要植物激素脱落酸和茉莉酸，并且由活性氧（ROS）产生的快速自动传播波介导。此外，这种反应取决于编码产生 ROS 的 NADPH 氧化酶 RBOHD 的基因以及各种气孔调节剂的功能，例如阴离子通道 SLAC1、GHR1（保卫细胞过氧化氢抗性 1）和脂氧合酶 1（LOX1）。我们的发现表明，植物作为高度动态和协调的生物体发挥作用，优化其冠层对波动光强的整体反应。
