Table_1_Research on the Physio-Biochemical Mechanism of Non-Thermal Plasma-Regulated Seed Germination and Early Seedling Development in Arabidopsis.doc

Non-thermal plasma holds great potentials as an efficient, economical, and eco-friendly seed pretreatment method for improving the seed germination and seedling growth, but the mechanisms are still unclear. Therefore, a plant model organism Arabidopsis thaliana was used to investigate the physio-biochemical responses of seeds to non-thermal plasma at different treatment times by measuring the plant growth parameters, redox-related parameters, calcium (Ca2+) level and physicochemical modification of seed surface. The results showed that short-time plasma treatment (0.5, 1, and 3 min) promoted seed germination and seedling growth, whereas long-time plasma treatment (5 and 10 min) exhibited inhibitory effects. The level of superoxide anion (O2•−) and nitric oxide (NO) and the intensity of infrared absorption of the hydroxyl group were significantly higher in short-time plasma treated Arabidopsis seeds, and the level of hydrogen peroxide (H2O2) was remarkably increased in long-time plasma treated seeds, indicating that O2•−, ·OH, and NO induced by plasma may contribute to breaking seed dormancy and advancing seed germination in Arabidopsis, while plasma-induced H2O2 may inhibit the seed germination. The intensity of hydroxyl group and the contents of H2O2, malondialdehyde, and Ca2+ in Arabidopsis seedlings were obviously increased with the plasma treatment time. Catalase, superoxide dismutase, and peroxidase activities as well as proline level in short-time treated seedlings were apparently higher than in control. The etching effects of plasma on seed surface were dose-dependent, spanning from slight shrinkages to detached epidermis, which also significantly increased the oxidation degree of seed surface. Therefore, the improved activities of antioxidant systems, moderate ·OH, H2O2, and Ca2+ accumulation and seed surface modification induced by plasma all contribute to the enhanced seedling growth of Arabidopsis after short-time plasma treatment.

非热等离子体作为一种高效、经济且环保的种子预处理方法，在提升种子发芽率和幼苗生长方面具有巨大的潜力，但其作用机制尚不明确。因此，本研究选取拟南芥（Arabidopsis thaliana）作为植物模式生物，通过测量植物生长参数、氧化还原相关参数、钙离子（Ca2+）水平及种子表面的物理化学改性，探究了不同处理时间下非热等离子体对种子生理生化反应的影响。研究结果表明，短时间等离子体处理（0.5、1和3分钟）能够促进种子发芽和幼苗生长，而长时间等离子体处理（5和10分钟）则表现出抑制作用。短时间等离子体处理的拟南芥种子中，超氧阴离子（O2•−）和一氧化氮（NO）水平以及羟基红外吸收强度显著升高，而在长时间等离子体处理的种子中，过氧化氢（H2O2）水平显著增加，这表明等离子体诱导的O2•−、·OH和NO可能有助于打破拟南芥的种子休眠并促进种子发芽，而等离子体诱导的H2O2可能抑制种子发芽。随着等离子体处理时间的增加，羟基强度、H2O2、丙二醛和Ca2+的含量在拟南芥幼苗中明显增加。短时间处理幼苗中的过氧化氢酶、超氧化物歧化酶和过氧化物酶活性以及脯氨酸水平明显高于对照组。等离子体对种子表面的蚀刻效应呈剂量依赖性，从轻微收缩到表皮脱落不等，这也显著提高了种子表面的氧化程度。因此，等离子体处理后，抗氧化系统活性增强、·OH、H2O2和Ca2+的适度积累以及种子表面的改性均有助于短时间等离子体处理后拟南芥幼苗生长的增强。