油菜是我国重要的油料作物，而长江流域冬油菜区是我国最大的油菜主产区。随该地区耕作制度的变化导致油菜茬口推迟，以及随着农村劳力资源的日趋紧张，农民对油菜直播简化栽培方式的需求也日益增强，晚直播油菜应运而生。但晚直播油菜在低温的不利环境条件下，油菜种子活力下降、萌发出苗受阻、出苗后苗势较弱，在冬季易遭受冷害及冻害并影响后期植株的生长发育。本试验以甘蓝型油菜（Brassica napus L.）南农油4号为试验材料，研究H2O2浸种处理对低温下油菜种子萌发和幼苗生长的影响以及对油菜幼苗抗氧化系统的影响，探讨H2O2浸种在低温胁迫条件下对油菜作用的生理机制，为晚直播油菜幼苗生长快、齐、壮提供理论依据与实用技术。试验结果表明： 1. H2O2浸种能提高种子发芽势，使油菜群体萌发进程更为一致。播期推迟，油菜平均出苗时间延长、成苗率降低、幼茎皱缩发生率和冻害指数升高，表明低温对油菜种子的萌发出苗具有显著的抑制作用，且在低温下长出的幼苗活力较弱，对环境的适应能力较差。H2O2浸种处理在一定程度上加快了油菜萌发出苗进程、提高了油菜幼苗成苗率，降低了生长过程中的幼茎皱缩发生率和冻害指数，表明H2O2浸种增强了苗势以更好的适应环境变化，缓解了低温对油菜生长的抑制效应，增加了油菜地上部干物质积累。 2. 不同叶龄幼苗抗氧化系统对冷害及冻害胁迫的响应程度有所差异。低温胁迫下，植株体内ROS大量积累，MDA含量较高。H2O2浸种处理不同程度的提高了超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）、三种抗氧化酶活性以及更有效的调节抗坏血酸过氧化物酶（APX）等A-G循环系统中的酶活及物质含量，使清除过量的ROS更加高效，降低了MDA含量。研究表明H2O2浸种能够促进油菜抗氧化酶活性及抗氧化剂含量升高，减少ROS伤害，提高了油菜抗寒性，从而增加了油菜干物质的积累。

Rapeseed is an important oil crop in China. Winter rapeseed area in the Yangtze River Basin is the largest main rapeseed producing area in China. With the change of cultivation system in this area, the stubble of rapeseed was delayed, and with the increasing shortage of labor resources in rural areas, farmers' demand for Simplified Cultivation Methods of rapeseed direct seeding was increasing, so late direct seeding rapeseed emerged as the times require. However, late direct seeding rapeseed is vulnerable to low temperature. Under adverse environmental conditions, rapeseed seed vigor decreases, germination seedlings are blocked, seedling vigor is weak after emergence, and it is vulnerable to cold injury and freezing injury in winter, affecting the growth and development of late plants. In this experiment, Brassica napus L. Nannongyou No. 4 was used as experimental material to study the effects of low temperature soaking with hydrogen peroxide on Seed Germination and seedling growth of rapeseed and on the antioxidant system of rapeseed seedlings. The physiological mechanism of H2O2 soaking on Rapeseed under low temperature stress was discussed, which provided theoretical basis and practical technology for rapeseed seedlings growing fast, uniform and strong in late direct seeding.The test results show that: 1. Soaking seeds with hydrogen peroxide（H2O2） can improve seed germination potential, which is more consistent with the process of rape population germination. The delay of sowing date, the prolongation of seedling emergence time, the decrease of seedling growth rate and the increase of young stem shrinkage rate and freezing injury index indicated that low temperature had a significant inhibitory effect on the germination of rapeseed seeds, and the seedling vigor grew at low temperature was weak, and the adaptability to the environment was poor. Soaking with H2O2 accelerated the germination process of rapeseed seedlings to a certain extent, increased the seedling rate of rapeseed seedlings, reduced the incidence of young stem shrinkage and freezing injury index in the growth process, which indicated that soaking with H2O2 enhanced seedling vigor to better adapt to environmental changes, alleviated the inhibition effect of low temperature on rapeseed growth, and increased dry matter accumulation in the above ground parts of rapeseed. 2. The response of antioxidant system of seedlings of different leaf ages to chilling and freezing stress is different. Under low temperature stress, ROS accumulated in plants and MDA content was higher. Soaking seeds with H2O2 increased the activities of three antioxidant enzymes, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and more effectively regulated the activity and content of ascorbic acid peroxidase (APX) ,etc in A-G circulatory system, which made the removal of excessive ROS more efficient and the content of MDA lower. The results showed that soaking seeds with H2O2 could increase the activity of antioxidant enzymes and the content of antioxidants, reduce ROS damage and improve cold resistance of rapeseed, thus increasing the accumulation of dry matter in rapeseed.