Table 2_Screening and identification of grain sorghum germplasm for salt tolerance at seedling stage.xlsx

IntroductionSorghum is characterized by its salt tolerance, and holds great potential for cultivation in saline-alkali soils.
MethodsThis study aimed to comprehensively evaluate the salt tolerance of grain sorghum germplasm. The experiment was conducted with 188 grain sorghum germplasm accessions selected to investigate the morphological and physiological index of seedlings under 150 mM NaCl stress. A comprehensive salt tolerance evaluation system was constructed using six indicators: shoot length (SL), root length (RL), shoot fresh weight (SFW), root fresh weight (RFW), shoot dry weight (SDW), and root dry weight (RDW). The salt tolerance level of the 188 accessions was evaluated using methods including the salt tolerant index (SI), the Spearman correlation analysis, the membership function analysis, the principal component analysis (PCA), and the cluster analysis.
ResultsThe results were classified into five categories: highly salt tolerant, salt-tolerant, moderate, salt-sensitive, and highly salt-sensitive. The comprehensive evaluation revealed significant variability in salt tolerance among the sorghum germplasm, with an overall trend of normal distribution. The loadings of shoot growth parameters (SFW and SDW) were relatively high, explaining most of the information in the first principal component. Therefore, shoot growth status can be used as an important standard for evaluating salt tolerance in sorghum. Among the accessions, LCS177 and LCS234 exhibited extremely high salt tolerance, while LCS140 and LCS181 showed highly sensitive of salt tolerance. Further analysis of the physiological characteristics of salt tolerance in the selected extreme accessions revealed that under salt stress, the increases in proline, soluble protein, and soluble sugar contents were significantly higher in the salt-tolerant accessions LCS177 and LCS234 than in the salt-sensitive accessions LCS140 and LCS181. In terms of oxidative stress, the activities of SOD, POD, and CAT were significantly higher in the salt-tolerant accessions LCS177 and LCS234, while the content of MDA was significantly lower in salt-tolerant accessions compared to that of in salt-sensitive accessions LCS140 and LCS181.
DiscussionThe results of this study provide a material basis for the improvement of salt tolerance in sorghum germplasm resources and for the breeding of salt-tolerant sorghum varieties.

**引言** 高粱具备耐盐特性，在盐碱土栽培领域拥有极高应用前景。

**材料与方法** 本研究旨在全面评估粒用高粱种质的耐盐性。试验选取188份粒用高粱种质材料，探究150 mM氯化钠（NaCl）胁迫下幼苗的形态与生理指标。本研究构建了包含6项指标的耐盐性综合评价体系，分别为地上部长度（shoot length, SL）、根长（root length, RL）、地上部鲜重（shoot fresh weight, SFW）、根鲜重（root fresh weight, RFW）、地上部干重（shoot dry weight, SDW）及根干重（root dry weight, RDW）。采用耐盐指数（salt tolerant index, SI）、斯皮尔曼相关性分析、隶属函数分析、主成分分析（principal component analysis, PCA）及聚类分析等方法，对188份种质的耐盐水平进行评价。

**结果与分析** 本研究将耐盐性划分为5个等级：高耐盐、耐盐、中度耐盐、盐敏感及高盐敏感。综合评价结果显示，不同高粱种质的耐盐性存在显著差异，整体呈正态分布趋势。地上部生长相关指标（地上部鲜重、地上部干重）的载荷量相对较高，解释了第一主成分中的绝大多数信息，因此地上部生长状况可作为评价高粱耐盐性的重要标准。供试种质中，LCS177与LCS234表现出极强的耐盐性，而LCS140与LCS181则表现为高度盐敏感。对筛选出的极端耐盐性种质进一步分析发现，盐胁迫下，耐盐种质LCS177、LCS234的脯氨酸（proline）、可溶性蛋白（soluble protein）及可溶性糖（soluble sugar）含量增幅显著高于盐敏感种质LCS140与LCS181。在氧化应激层面，耐盐种质LCS177、LCS234的超氧化物歧化酶（superoxide dismutase, SOD）、过氧化物酶（peroxidase, POD）及过氧化氢酶（catalase, CAT）活性显著更高，而丙二醛（malondialdehyde, MDA）含量则显著低于盐敏感种质LCS140与LCS181。

**讨论** 本研究结果为高粱种质资源的耐盐性改良及耐盐高粱品种选育提供了材料基础。