Exogenous melatonin ameliorates salinity-induced oxidative stress and improves photosynthetic capacity in sweet corn seedlings

Abstract

Melatonin (MT) is involved in physiological processes in plants under abiotic stress. In this study, we investigated the effects of melatonin on maize photosynthetic and antioxidant capacities under salinity stress. Our findings indicated salinity stress significantly inhibited maize growth. However, exogenous MT promoted maize growth and antioxidant capacity. Superoxide dismutase, peroxidase, and catalase increased by 138.8, 38.7, and 32.0%, respectively, while H2O2 and malondialdehyde decreased by 23 and 31%, respectively. Exogenous MT also improved maize photosynthesis under salinity stress. Net photosynthetic rate, transpiration rate, and stomatal conductance increased by 134, 67.2, and 46.3%, respectively. Maximum quantum yield of PSII photochemistry, effective quantum yield of PSII photochemistry, photochemical quenching coefficient, and electron transport rate increased by 5.8, 70.4, 65.3, and 41.0%, respectively. Therefore, our findings suggested exogenous MT significantly ameliorated maize physiological and photosynthetic adaptation under salinity stress, thereby providing helpful guidance for maize cultivation in areas of high salinity. Highlights • Exogenous melatonin (MT) mediated physiological and photosynthetic adaptation in sweet corn • Exogenous MT maintained the balance of ROS metabolism under salinity stress • Exogenous MT ameliorated salinity-induced damages of sweet corn seedlings et al. 2020). Several studies have reported a significant decline in growth and biomass yield of plants under salinity stress (Ahanger et al. 2018, Alam et al. 2019). The effects of salinity stress on photosynthesis have several outcomes. A decrease in stomatal conductance leads to a decrease in carbon dioxide assimilation. Moreover, salinity stress is associated with a decrease in chlorophyll (Chl) content,

Exogenous spermidine enhances the photosynthetic and antioxidant capacity of citrus seedlings under high temperature

“…H 2 O 2 was determined by using the method reported by Wang et al . 30 with minor modification. 0.5 g of fresh leaves homogenized with 5 mL of 0.1% (w/v) TCA in an ice bath.…”

Recent Progress on Melatonin-Induced Salinity Tolerance in Plants: An Overview

“…Melatonin was first described in the animal pineal gland. Today, it is known to be synthesized by various plants (Wang et al, 2021). Melatonin is synthesized in mitochondria and chloroplasts in plants (Siddiqui et al, 2019).…”

“…Melatonin application increased leaf antioxidant enzymes and abscisic acid, and decreased salt stress in strawberries (Zahedi et al, 2020). Some researchers emphasized that exogenous treatment of melatonin induces the activities of some antioxidant enzymes, including SOD, POD and CAT, under salt stress, and reduces MDA and electrolyte leakage (Jiang et al, 2016b;Chen et al, 2018;Mohamadi and Karimi, 2020;Park et al, 2021;Wang et al, 2021).…”

“…improve SOD, POD, CAT, photosynthesis, transpiration rate, stomatal conductance decreases H2O2 accumulation, malondialdehyde (MDA) (Wang et al, 2021) Sugar beet (Beta vulgaris L.) increase shoot and root fresh weight, shoot and root dry weight, leaf area, root length, promote photosynthesis, maintain ion homeostasis, removal of ROS, strengthen antioxidant defense system (Zhang et al, 2021) The various effects of melatonin on morphological, physiological and biochemical properties under salinity stress have been summarized in Table 1.…”

“…Higher production of ROS damages membranes, breaks the DNA chain, and inactivates various vital enzymes through lipid peroxidation (Li et al, 2017). Melatonin (MEL), a small molecular weight and tryptophan derivative indolamine molecule found in all kingdoms, from prokaryotes to eukaryotes, animals to plants (Kabiri et al, 2018;Varghese et al, 2019;Xu et al, 2019;Wang et al, 2021) as well as a free radical scavenger and broad-spectrum antioxidant, and plays a role in various biological processes in plants (Dawood and El-Awadi, 2015;Ke et al, 2018). In the past studies, it has given information about melatonin formation and exogenous application of melatonin in plants exposed to abiotic stress.…”