Effects of melatonin on germination and amino acid content in different wheat varieties seeds under polyethylene glycol stress

In this research, the effects of melatonin on germination and amino acid content in wheat (Triticum aestivum L.) seeds under polyethylene glycol (PEG-6000) stress were investigated. The results revealed that 10 M melatonin could aggravate the adverse effects of drought stress on germination percentage, germination index, and germination potential of two wheat varieties (JM22 and HG35). However, 300 M melatonin could obviously alleviate the negative effect of water stress on germination and increase radicle length, radicle number and plumule length of germinated seeds. Principal component analysis showed that amino acid content apparently changed in germination and the variation amplitude was different due to melatonin concentrations and wheat varieties. Lys content in wheat seed under 300 M melatonin plus PEG treatment increased compared with that under PEG. Meanwhile, Lys content was significantly and positively correlated with germination percentage, germination index, germination potential, radicle length, and plumule length, respectively. Our results suggested Lys play an important role in the regulation of melatonin on drought resistance of wheat seed during germination. This may be of value for saving water resources in North China Plain.