Exogenous Melatonin Alleviates Oxidative Damages and Protects Photosystem II in Maize Seedlings Under Drought Stress

Abstract

The protective role of melatonin in plants against various abiotic stresses have been widely demonstrated, but poorly explored in organ-specific responses and the transmission of melatonin signals across organs. In this study, the effects of melatonin with the root-irrigation method and the leaf-spraying method on the antioxidant system and photosynthetic machinery in maize seedlings under drought stress were investigated. The results showed that drought stress led to the rise in reactive oxygen species (ROS), severe cell death, and degradation of D1 protein, which were mitigated by the melatonin application. The application of melatonin improved the photosynthetic activities and alleviated the oxidative damages of maize seedlings under the drought stress. Compared with the leaf-spraying method, the root-irrigation method was more effective on enhancing drought tolerance. Moreover, maize seedlings made organ-specific physiological responses to the drought stress, and the physiological effects of melatonin varied with the dosage, application methods and plant organs. The signals of exogenous melatonin received by roots could affect the stress responses of leaves, and the melatonin signals perceived by leaves also led to changes in physiological metabolisms in roots under the stress. Consequently, the whole seedlings coordinated the different parts and made a systemic acclimation against the drought stress. Melatonin as a protective agent against abiotic stresses has a potential application prospect in the agricultural industry.

Exogenous melatonin improves glutathione content, redox state and increases essential oil production in two Salvia species under drought stress

“…2). These results are consistent with Huang et al 52 and Ahmad et al 53 who reported that melatonin application alleviated the negative effects of oxidative stress and ROS production. Even at mild water stress (60% FC), a reduced Fv/Fm ratio was recorded in the two species, and a more intense water stress (40% FC) had a further negative effect on this physiological parameter (Fig.…”

Role of melatonin in improving growth, yield quantity and quality of Moringa oleifera L. plant under drought stress

“…However, growth and yield reductions by drought were alleviated significantly by different concentrations (50, 100, and 150 mM) of melatonin (Tables 2 and 3). Earlier studies have confirmed that melatonin acted as a growth regulator of plant and thus could increase growth parameters in various plants (Li et al (2015), Liu et al (2015), Ye et al (2016), Cui et al (2017), Kabiri et al (2018), and Huang et al (2019)). Melatonin treatment could alleviate the adverse effects of drought stress on M. oleifera plant via improving their growth and physiological attributes.…”

“…Melatonin could alleviate the harmful effects of oxidative damages on proteins, lipids, and nucleic acids via its role as ROS scavenger or by regulating nonenzymatic antioxidants or enzymatic antioxidant biosynthesis or activities (Li et al 2015). The improved role of melatonin on decreasing oxidative damage induced by water deficit has been proven earlier in different plant species of cucumber (Zhang et al 2014a), apple (Li et al 2015), soybean (Wei et al 2015), wheat (Sadak 2016a), Moldavian balm (Kabiri et al 2018), and maize (Huang et al 2019). Treatment of plants with melatonin enables plants to tolerate abiotic stress via enhancing the recovery potential (Tan et al 2012b).…”

Effects of Light Quality and Phytochrome Form on Melatonin Biosynthesis in Rice

“…Melatonin acts as a hormone in plants, and as a signaling molecule in a wide range of biological activities [5]. For example, melatonin treatment enhances plant tolerance against many stresses, including salt [6,7], drought [8,9], viruses [10], pathogens [11,12], waterlogging [13], and senescence [14], among others [15][16][17]. Melatonin is also involved in plant development processes such as growth [18,19], seed viability [20], flowering [21,22], endoplasmic reticulum (ER) quality control [23,24], secondary metabolite synthesis [25], and others [26].…”