Regulation of Proline Metabolism in Soybean Leaves Under Drought Stress at Seedling Phase

Soybean is the most important oil crop globally; however, droughts are expected to seriously affect the growth and development of soybean in the context of climate change. In this study, polyethylene glycol (PEG) was used to simulate drought to explore the regulation of proline metabolism in soybean leaves under different degrees of drought stress at the seedling stage. The results showed that the activities of ornithine aminotransferase and Δ1-pyrroline-5-carboxylate synthetase increased while the activities of proline dehydrogenase decreased with an increase in drought stress. During the same number of treatment days, the higher the degree of drought stress, the greater the increase or decrease in enzyme activity. The content of leaf proline increased gradually with an extension in stress time at PEG concentrations of 5% and 10%, first increased and then decreased at PEG concentrations of 15% and 20%, and the peak value appeared on the 7th and 9th day, respectively.