番茄种质种子萌发期耐盐性综合评价及关键指标筛选

Comprehensive evaluation of salt tolerance during the germination period of tomato germplasm and Screening of key indicators

  • 摘要: 本研究旨在筛选番茄萌发期的耐盐种质资源并确定其关键评价指标. 为确定最适胁迫浓度,首先采用6份番茄种质,设置质量分数为0(CK)、0.2%、0.4%、0.6%、0.8%、1.0%共6个NaCl浓度梯度进行处理. 通过测定胚根长度,确定0.6%为最适筛选浓度. 进而以20份番茄种质为材料,在0.6% NaCl质量分数下处理并测定其发芽率、发芽势、发芽指数、活力指数、胚根长、胚轴长及鲜重共8项指标。在计算各项指标耐盐系数的基础上,综合运用相关性分析、主成分分析、隶属函数法和聚类分析进行耐盐性综合评价,并通过回归分析筛选关键指标. 结果显示,NaCl胁迫呈现“低促高抑”效应:质量分数0.2%~0.4%的处理促进多数材料胚根伸长,0.6%的处理则显著抑制,0.8%~1.0%的处理导致部分材料不萌发. 各指标的耐盐系数之间均呈显著相关(p<0.05),主成分分析提取出2个主成分,其累积贡献率达78.114%. 聚类分析将20份材料分为高度耐盐型(2份)、中度耐盐型(15份)和敏感型(3份). 最终,回归分析确定发芽指数、胚根长及鲜重为评价萌发期耐盐性的关键指标. 本研究建立了番茄萌发期的耐盐评价体系,筛选出了优异的耐盐种质和关键指标,为耐盐机理研究和品种改良提供了重要依据.

     

    Abstract: This study aimed to screen for salt-tolerant tomato germplasms at the germination stage and to identify key evaluation indicators for this trait. To determine the optimal stress concentration, six tomato germplasms were first treated with five NaCl stress concentrations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) alongside a 0 control (CK). Based on radicle length measurements, 0.6% NaCl was identified as the optimal screening concentration. Subsequently, 20 tomato germplasms were treated with 0.6% NaCl, and eight indicators were measured, including germination rate, germination potential, germination index, vigor index, radicle length, hypocotyl length, and fresh weight. After calculating the salt tolerance coefficient for each indicator, a comprehensive evaluation of salt tolerance was conducted using correlation analysis, principal component analysis (PCA), the subordinate function method, and cluster analysis, followed by regression analysis to screen for key indicators. The results showed that NaCl stress exhibited a hormetic effect, where low concentrations (0.2%–0.4%) promoted radicle elongation in most germplasms, while the 0.6% treatment caused significant inhibition and higher concentrations (0.8%–1.0%) prevented germination in some materials. The salt tolerance coefficients of all indicators were significantly correlated (p<0.05). PCA extracted two principal components with a cumulative contribution rate of 78.114%. Cluster analysis classified the 20 germplasms as highly tolerant (2), moderately tolerant (15), or sensitive (3). Finally, regression analysis identified germination index, radicle length, and fresh weight as the key indicators for evaluating salt tolerance at the germination stage. This study established a comprehensive evaluation system for tomato salt tolerance during germination, screened superior germplasms and key indicators, and provides a foundation for future research on salt tolerance mechanisms and variety improvement.

     

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