Exogenous Proline Alleviated Low Temperature Stress in Maize Embryos by Optimizing Seed Germination, Inner Proline Metabolism, Respiratory Metabolism and a Hormone Regulation Mechanism

作者：Shiyu Zuo, Jing Li, Wanrong Gu, Wei Shi · 发表于：Agriculture · 年份：2022 · DOI：10.3390/agriculture12040548 · 被引用次数：38 · 研究领域：Seed Germination and Physiology、Plant Stress Responses and Tolerance、Plant responses to water stress

Proline (Pro) is not only an important osmotic adjustment substance, but it also plays an important role in regulating plant abiotic stress resistance. The maize varieties, Xinxin 2 (low temperature insensitive) and Damin 3307 (low temperature sensitive), were chosen as materials, setting a normal temperature for germination (22 °C/10 °C, 9d), low temperature germination (4 °C/4 °C, 5d) and normal temperature recovery (22 °C/10 °C, 4d), combined with a proline (15 mmol·L−1) soaking treatment, to reveal the seed germination and regulation mechanism in maize embryos. The results showed that proline significantly improved the germination potential, germination rate, germination index and vigor index of seeds under low temperature stress, increasing the length of the coleoptile and radicle, increasing the dry and fresh weight of young buds (coleoptile + radicle), and increasing the activity of α-amylase. Proline enhanced the activities of Δ1-pyrroline-5-carboxylic acid synthetase (P5CS) and ornithine aminotransferase (OAT) in maize embryos under low temperature stress, enhanced the proline synthesis pathways, and further enhanced proline accumulation. Proline induced the activity of proline dehydrogenase (ProDH) in the early stage of low temperature stress and stress relief. Under low temperature stress, the activities of hexokinase (HXK), phosphofructokinase (PFK), pyruvate kinase (PK), isocitrate dehydrogenase (IDH), succinate dehydrogenase (SDH), malate dehydrogenase (MDH) and...