Analysis of melatonin regulation of germination and antioxidant metabolism in different wheat cultivars under polyethylene glycol stress

Abstract

Melatonin is effective in enhancing various abiotic stress resistances of plants. However, its underlying mechanisms in drought-resistance in winter wheat (Triticum aestivum L.) is not clear. The goal of this work was to investigate the effect of melatonin on seed germination and to evaluate leaf antioxidant physiology for two wheat varieties. Experiments included 20% PEG, melatonin plus 20% PEG and a control using two contrasting wheat varieties (JM22-drought sensitive and HG35-drought resistant). Melatonin levels were 0, 1, 10, 100 and 300 μmol L-1. Results revealed that 300 μmol L-1 of melatonin alleviated the negative effect of water stress on germination and increased radicle length, radicle number, and plumule length of the germinated seeds. Principal component analysis showed a significant change in amino acid content during germination and this change was dependent on melatonin concentration and the variety. Lysine (Lys) content in wheat seeds under the PEG plus 300 μmol L-1 melatonin treatment increased compared with that of the seeds under PEG alone. There was a significant and positive correlation between Lys content and morphological index of germination. During seedling growth, soluble protein was involved in osmotic adjustment and superoxide dismutase (SOD) activity was increased to mitigate the damage in the cytomembrane of JM 22 leaf under 300 μmol L-1 melatonin plus PEG treatment. The effect of melatonin was dependent on SOD activity increasing significantly for HG35-a drought resistant variety. The results of this work lays a foundation for further studies to determine if melatonin can be economically used to mitigate the impact of dry planting conditions on wheat productivity in North China Plain.

Exogenous Melatonin Promotes the Salt Tolerance by Removing Active Oxygen and Maintaining Ion Balance in Wheat (Triticum aestivum L.)

“…Salt stress promoted storage protein degradative, and thus, amino acid content changed accordingly (Zhang et al, 2017). Lysine (Lys) content is decreased with MT and transforms into other substances to raise the level of stress tolerance in wheat seeds during germination under drought stress (Li et al, 2020). MT also accelerates the metabolic flow from the precursor amino acids arginine and methionine to polyamines and decreases the degradation of salt-induced polyamines (Ke et al, 2018).…”

“…Totally, two layers of filter paper saturated with three different treatment solutions: CK (distilled water), NaCl (100 mM), and NaCl-MT (100 mM NaCl + 300 µM MT) were placed in each plate. The concentrations of NaCl and MT solutions were selected referring to , Ke et al (2018), and our former study (Li et al, 2020). The germination conditions were set at a light/dark shift (12/12h).…”

“…MT at 200 µmol L −1 can effectively inhibit ROS production, improve the biomass and chlorophyll content, and regulate the photosynthetic characteristics of cotton seedlings under salt stress (Jiang et al, 2021). MT at 300 µmol L −1 alleviates the negative effect of water stress on wheat germination and promotes morphological development including radicle length, radicle number, and plumule length of germinated seeds (Li et al, 2020). About 800 µmol L −1 MT used for priming seed significantly improves germination energy, germination percentage, proline content, and total phenolic content of maize (Jiang X. et al, 2016).…”

Induction of Low Temperature Tolerance in Wheat by Pre-Soaking and Parental Treatment with Melatonin

“…Melatonin also enhanced the seed germination by osmotic regulation under salt stress in cotton [ 28 ]. It could activate the antioxidant systems to protect the seeds against drought-induced oxidative stress in wheat [ 29 ]. A similar result was found in Phacelia tanacetifolia , in which melatonin combined with priming medium significantly alleviated the negative effects of light and high temperature on seed germination [ 30 ].…”

Rehydration Compensation of Winter Wheat Is Mediated by Hormone Metabolism and De-Peroxidative Activities Under Field Conditions

“…Drought-tolerant variety Hengguan35 (HG, sourced from Drought Agricultural Experiment Station of Hebei Academy of Agriculture and Forestry Sciences, Hebei, China) and drought-sensitive variety Shinong086 (SN, sourced from Hebei Dadi Seed Industry Co., Ltd., Hebei, China) were used in this study ( Li D. et al, 2020 ). The seeds were sown in a field at the Shenzhou Experimental Station of Arid Crops Research Institute, Hebei Academy of Agriculture and Forestry Sciences (Hebei, China, 37.91°N, 115.71°E) on October 13, 2018.…”