Ameliorative effect of melatonin improves drought tolerance by regulating growth, photosynthetic traits and leaf ultrastructure of maize seedlings

• Published in: BMC plant biology Vol. 21; no. 1; pp. 1 - 368
• Main Authors: Ahmad, Shakeel, Muhammad, Ihsan, Wang, Guo Yun, Zeeshan, Muhammad, Yang, Li, Ali, Izhar, Zhou, Xun Bo
• Format: Journal Article
• Language: English
• Published: London BioMed Central Ltd 12.08.2021; BioMed Central; BMC
• Subjects: Abiotic stress; Antioxidant enzymes; Antioxidants; Biomass; Carotenoids; China; Corn; Drought; Drought resistance; Drought stress; Droughts; Environmental aspects; Enzymatic activity; Field capacity; Gene expression; Growth regulators; Hardiness; Leaf ultrastructure; Maize; Malondialdehyde; Melatonin; Moisture content; Oxidative stress; Photosynthesis; Photosynthetic pigments; Physiological aspects; Physiology; Pigments; Plant growth; Plant growth promoting substances; Plant species; Plants; Proteins; Reactive oxygen species; Seedlings; Soils; Stomata; Sugar; Ultrastructure; Water content; China
• ISSN: 1471-2229; 1471-2229
• DOI: 10.1186/s12870-021-03160-w

Melatonin is considered a potential plant growth regulator to enhance the growth of plants and increase tolerance to various abiotic stresses. Nevertheless, melatonin's role in mediating stress response in different plant species and growth cycles still needs to be explored. This study was conducted to understand the impact of different melatonin concentrations (0, 50, 100, and 150 [mu]M) applied as a soil drench to maize seedling under drought stress conditions. A decreased irrigation approach based on watering was exposed to maize seedling after drought stress was applied at 40-45% of field capacity. The results showed that drought stress negatively affected the growth behavior of maize seedlings, such as reduced biomass accumulation, decreased photosynthetic pigments, and enhanced the malondialdehyde and reactive oxygen species (ROS). However, melatonin application enhanced plant growth; alleviated ROS-induced oxidative damages by increasing the photosynthetic pigments, antioxidant enzyme activities, relative water content, and osmo-protectants of maize seedlings. Melatonin treatment also enhanced the stomatal traits, such as stomatal length, width, area, and the number of pores under drought stress conditions. Our data suggested that 100 [mu]M melatonin application as soil drenching could provide a valuable foundation for improving plant tolerance to drought stress conditions.