Department of Plant Science, Faculty of Science, Shahrekord University, Iran.
Department of Plant Science, Faculty of Science, Shahrekord University, Iran; Research Institute of Biotechnology, Shahrekord University, Shahrekord, Iran.
Plant Physiol Biochem. 2019 Jun;139:548-557. doi: 10.1016/j.plaphy.2019.04.021. Epub 2019 Apr 17.
Stress priming (pre-exposure of plants to various types of moderate stresses) could affect plant responses to subsequent severe stresses. Drought stress is one of the major threats to plants which reduces the global agricultural productions. Here we demonstrated that light emitting diodes (LEDs)-driven tolerant to drought stress in lemon balm plantlets was highly correlated with priming with these lighting sources. Plantlets of the two genotypes of M. officinalis L. were first grown in 4 incubators with different LED lamps, including white LEDs (380-760 nm), blue LEDs (460 nm), red LEDs (650 nm) and red + blue LEDs (70%:30%), in a greenhouse for 4 weeks. The potted plants were then subjected to drought stress. Under drought stress, LED-primed plants maintained significantly higher fresh and dry weight, relative water content (RWC), concentration of soluble sugars, antioxidant activity and higher content of proline, HO, abscisic acid (ABA) and rosmarinic acid than non-primed plants. The results of Real-Time RT-PCR confirmed that LED pretreatment up-regulated the expression levels of respiratory burst oxidase homologues (RBOHs) or NADPH oxidase, 9-cis epoxy carotenoid dioxygenase (NCED), and rosmarinic acid synthase (RAS), while down-regulated that of ABA 8'-hydroxylase (ABA8Ox). These findings suggest, for the first time, that pre-treatment of plants with red + blue LEDs could improve their growth and quality under drought stress.
胁迫预处理（植物暴露于各种类型的适度胁迫下）可能会影响植物对后续严重胁迫的反应。干旱胁迫是植物面临的主要威胁之一，它降低了全球农业产量。在这里，我们证明了发光二极管（LED）驱动的柠檬香脂植物幼苗对干旱胁迫的耐受性与这些光源的预处理高度相关。两种基因型的柠檬香脂（M. officinalis L.）的植物幼苗首先在 4 个带有不同 LED 灯的培养箱中生长，包括白色 LED（380-760nm）、蓝色 LED（460nm）、红色 LED（650nm）和红+蓝 LED（70%：30%），在温室中生长 4 周。然后将盆栽植物置于干旱胁迫下。在干旱胁迫下，LED 预处理的植物保持了显著更高的鲜重和干重、相对含水量（RWC）、可溶性糖浓度、抗氧化活性以及脯氨酸、HO、脱落酸（ABA）和迷迭香酸的含量均高于未预处理的植物。实时 RT-PCR 的结果证实，LED 预处理上调了呼吸爆发氧化还原酶同源物（RBOHs）或 NADPH 氧化酶、9-顺式环氧类胡萝卜素双加氧酶（NCED）和迷迭香酸合酶（RAS）的表达水平，而下调了 ABA8'-羟化酶（ABA8Ox）的表达水平。这些发现首次表明，用红+蓝 LED 预处理植物可以在干旱胁迫下改善其生长和品质。
