College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, China.
Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Nanjing Forestry University, Nanjing, 210037, China.
Sci Rep. 2020 Dec 16;10(1):22066. doi: 10.1038/s41598-020-79043-1.
Pinus massoniana Lamb. is one of the most sensitive species to acid deposition among forest woody plants, but differences in acid resistance among pine families still exist. It is of great significance to study the differences in acid resistance of Masson pine families and to analyze the physiological regulation mechanism of their acid resistance. In this study, the 100-day-old seedlings of 16 Masson pine families were treated with the simulated acid rain (SAR) at different pH levels (5.6, 4.5, 3.5 and 2.5) for 100 days to investigate the plant morphology, chlorophyll content, and root physiological responses. Results showed that pine family No. 35 maintained the good morphology, high chlorophyll content and organic acids secretion, and low plasma membrane permeability exposed to SAR, while family No. 79 presented the opposite. SAR not only increased the root plasma membrane permeability, but also induced an exudation of organic acids from the pine roots, and the test parameters changed sharply when the SAR pH was lower than 4.5. The results indicated that Masson pine could resist to acidic environment (pH 4.5-5.6), and family No. 35 had the acid resistance while the family No. 79 was sensitive to acid stress. The acid resistance diversity of different pine families had close relation with the root physiological processes, including the root plasma membrane permeability and organic acids secretion. For the future research, the natural genetic variation of Masson pine in response to acid stress and its acid resistance mechanism should be further studied.
马尾松是木本植物中对酸沉降最敏感的物种之一，但松科不同树种之间的耐酸能力仍存在差异。研究马尾松家系耐酸能力的差异，分析其耐酸的生理调控机制，具有重要意义。本研究采用不同 pH 值（5.6、4.5、3.5 和 2.5）的模拟酸雨（SAR）处理 16 个马尾松家系 100 日龄幼苗 100 天，研究植物形态、叶绿素含量和根系生理响应。结果表明，SAR 处理下，第 35 号家系马尾松保持良好的形态、高叶绿素含量和有机酸分泌，以及低的质膜透性；而第 79 号家系则表现相反。SAR 不仅增加了根系质膜的通透性，还诱导马尾松根系有机酸的分泌，当 SAR pH 值低于 4.5 时，测试参数变化剧烈。结果表明，马尾松能够耐受酸性环境（pH 4.5-5.6），第 35 号家系具有耐酸能力，而第 79 号家系对酸胁迫敏感。不同马尾松家系的耐酸能力多样性与根系生理过程密切相关，包括根系质膜通透性和有机酸分泌。未来的研究应进一步研究马尾松对酸胁迫的自然遗传变异及其耐酸机制。
