Abstract: The development and utilization of saline-alkali land is a key focus for grassland improvement in China， and enhancing the germination capacity of native grass seeds is a crucial step of this process. In this study seeds of Mongolian wheatgrass （Agropyron mongolicum） was used as the material to investigate the effects of nano-iron particle suspensions at different concentrations （25， 50， 75 and 100 mg·L^-1） and different priming duration （4 h and 36 h） on seeds germination， seedling growth characteristics and antioxidant enzyme activities of seedling under 175 mmol·L^-1 mixed salt solution stress （NaCl∶Na₂SO₄=5∶1）. Multispectral imaging technology was also used to rapidly and visually assess seedling vigor and to screen for the most salt-tolerant priming treatments. The results showed that the priming treatment with 4 h significantly outperformed than the 36 h treatment according to the analysis of seed germination and seedling growth indexes （P<0.05）. Nano-iron priming for 4 h at all concentrations significantly improved the germination percentage and germination index （P<0.05）， reduced mean germination time， and increased seedling height， fresh weight， vigor index， and antioxidant enzyme activities （e.g. POD， CAT， APX and MDHAR） in the seedlings （P<0.05）. The nCDA images from multispectral imaging were highly consistent with the trends of these physiological and biochemical changes. Among all the treatments， 50 mg·L^-1 nano-iron priming for 4 h was the most effective， significantly enhancing germinability and growth performance of Mongolian wheatgrass under salt stress and markedly improving its salt tolerance. These findings provide important scientific evidence for vegetation restoration and ecological rehabilitation in saline-alkali lands.

Key words: Mongolian wheatgrass, Salt tolerance, Seed priming, Nano-iron

摘要： 盐碱地的开发利用是我国草地改良的重点，提高乡土草种种子发芽能力是草地建设的关键环节。试验以蒙古冰草（Agropyron mongolicum）种子为材料，在175 mmol·L^-1混合盐溶液胁迫下（NaCl∶Na₂SO₄=5∶1），探究不同浓度（25，50，75和100 mg·L^-1）纳米铁颗粒悬浮液和不同时间（4 h和36 h）的引发处理对于蒙古冰草种子发芽、幼苗生长特性和抗氧化酶活性的影响，并利用多光谱成像技术快速直观地判定幼苗活力，筛选耐盐性强的引发处理。结果表明：在种子发芽和幼苗生长相关指标测定中，引发4 h效果显著优于36 h（P<0.05）。4 h引发处理时不同浓度的纳米铁能显著提高蒙古冰草的发芽率和发芽指数（P<0.05），平均发芽时间缩短，幼苗的苗长、鲜重、活力指数及幼苗中过氧化物酶（Peroxidase，POD）、过氧化氢酶（Catalase，CAT）、抗坏血酸过氧化物酶（Ascorbate peroxidase，APX）和单脱氢抗坏血酸还原酶（Monodehydroascorbate reductase，MDHAR）等抗氧化酶活性显著提高（P<0.05），多光谱成像获取的归一化典型判别分析（nCDA）图像结果与上述生理生化指标变化趋势高度一致。综合分析，50 mg·L^-1纳米铁引发蒙古冰草种子4 h处理效果最佳，能有效增强蒙古冰草在盐胁迫下的发芽与生长性能，显著提升其耐盐性，为盐碱地植被恢复和生态修复提供了重要的科学依据。

关键词: 蒙古冰草, 耐盐性, 种子引发, 纳米铁