Abstract: Double haploid（DH） inbred lines of Chinese cabbage with excellent field comprehensive traits were used as experimental materials. Seed germination tests were conducted using four NaCl concentration gradients（0，170，220，300 mmol/L）via the petri dish germination method，and salt⁃tolerant germplasm at the germination stage was screened by calculating germination potential and germination rate. Furthermore，the salt⁃tolerant and salt⁃sensitive materials obtained from the germination⁃stage screening were further subjected to salt stress treatment at the seedling stage with NaCl concentration gradients of 0，25，50，100，and 150 mmol/L. Growth indicators such as root length and fresh weight were measured to analyze their salt tolerance at the seedling stage. On this basis，using the salt⁃tolerant material HN315 and the salt⁃sensitive material HN44 as core research objects，BrSOS family genes were identified based on the Chinese cabbage whole⁃genome database，and the expression patterns of each gene were analyzed after 36 h of treatment with different NaCl concentrations. The results showed that among 18 Chinese cabbage DH materials，4 salt⁃sensitive materials，4 salt⁃tolerant materials，and 10 intermediate materials were identified. Low⁃concentration NaCl stress could promote the growth of Chinese cabbage to a certain extent，and materials that were salt⁃sensitive at the germination stage still exhibited salt sensitivity at the seedling stage. Gene expression analysis showed that after salt stress treatment，BraA04g013320.3.5C was downregulated in the salt⁃sensitive material HN44，while under high⁃salt conditions，BraA06g032880.3.5C and BraA09g006370.3.5C were significantly upregulated.In the salt⁃tolerant material HN315，BraA04g013320.3.5C and BraA02g044060.3.5C were downregulated，whereas the expression levels of BraA06g032880.3.5C and BraA09g006370.3.5C increased continuously with rising NaCl concentrations.In conclusion，this study completed the evaluation of salt tolerance in Chinese cabbage germplasm through screening at the seed germination and seedling stages，found that BrSOS family genes showed significant expression differences between salt⁃tolerant and salt⁃sensitive Chinese cabbage materials，and clarified that this gene family was a key gene family involved in salt stress response and salt tolerance regulation in Chinese cabbage.

Key words: Chinese cabbage, Salt tolerance, Salt sensitivity, BrSOS gene family, Salt stress, NaCl concentration gradient, Seedling salt tolerance, Expression analysis

摘要： 以田间综合性状优良的大白菜双单倍体（DH）自交系为试验材料，设置0、170、220、300 mmol/L 4个NaCl浓度梯度，采用培养皿催芽法进行种子萌发试验，通过测定萌发势、萌发率，开展大白菜萌发期耐盐种质资源筛选。在此基础上，进一步以萌发期筛选获得的耐盐和盐敏感材料为对象，设置0、25、50、100、150 mmol/L NaCl浓度梯度进行苗期盐胁迫处理，测定根长、鲜质量等生长指标，分析其苗期耐盐性。进而以耐盐材料HN315 和盐敏感材料HN44 为研究对象，基于大白菜全基因组数据库鉴定BrSOS 基因家族，并分析各基因在不同浓度NaCl处理36 h后的表达模式。结果表明，在供试的18份大白菜DH材料中，筛选出4份盐敏感材料、4份耐盐型材料及10份中间型材料。低浓度NaCl胁迫可在一定程度上促进大白菜生长，且萌发期盐敏感的材料在苗期仍表现出盐敏感性。基因表达分析显示，盐胁迫处理后，盐敏感材料HN44 中BraA04g013320.3.5C表达下调，高盐条件下BraA06g032880.3.5C和BraA09g006370.3.5C表达显著上调；耐盐材料HN315中BraA04g013320.3.5C和BraA02g044060.3.5C表达下调，而BraA06g032880.3.5C和BraA09g006370.3.5C表达量随盐浓度升高持续上升。综上，通过种子萌发期和苗期耐盐性筛选，完成了大白菜种质耐盐性评价，发现BrSOS 基因家族在耐盐与盐敏感大白菜材料中存在显著表达差异，明确该基因家族是大白菜响应盐胁迫、调控耐盐性的关键基因家族。

关键词: 大白菜, 耐盐, 盐敏感, BrSOS基因家族, 盐胁迫, NaCl浓度梯度, 苗期耐盐, 表达分析