The presence of epidermal bladder cells (EBCs) in halophytes allows considerable amount of Na+ being accumulated in these external structures, away from the metabolically active mesophile cells. Also, stomatal patterning may represent a primary mechanism by which plants can optimise its water-use efficiency under saline condition. This investigation was aimed to explore the varietal differences in a salinity tolerance of quinoa (Chenopodium quinoa) by evaluating a broad range of accessions and linking the overall salinity tolerance with changes in stomatal characteristics and EBC parameters. One hundred and fourteen accessions were grown under temperature-controlled glasshouse under non-saline and 400 mM NaCl conditions, and different physiological and anatomical characteristics were measured. Accessions were classified into three classes (sensitive, intermediate and tolerant) based on a relative dry weight defined as salinity tolerance index (STI). Results showed a large variability in STI indicating a strong genetic variation in salinity tolerance in quinoa. Bladders density was increased in a majority of accessions under saline condition while the bladder’s diameter remained unchanged; this resulted in a large variability in a bladder’s volume as a dependant variable. Stomata density remained unchanged between saline and non-saline conditions while the stomata length declined between 3% to 43% amongst accessions. Leaf Na+ concentration varied from 669 μmol/gDW to 3155 μmol/gDW under saline condition and, with an exception of a few accessions, leaf K+ concentration increased under saline conditions. Correlation analysis indicated a significant positive association between EBC diameter and STI on one hand and EBC volume and STI on the other hand, in a salt-tolerant group. These observations are consistent with the role of EBCs in sequestration of toxic Na+ in the external structures, away from the cytosol. A negative association was found between EBC density and diameter in salt-sensitive plants. A negative association between STI and stomata length was also found in a salt-tolerant group, suggesting that these plants were able to efficiently regulate stomatal patterning to balance water loss and CO2 assimilation under saline conditions. Both salt-sensitive and salt-tolerant groups had the same Na+ concentration in the shoot under saline conditions; however, a negative association between leaf Na+ concentration and STI in salt-sensitive plants indicated a more efficient Na+ sequestration process into the EBCs in salt-tolerant plants.

中文翻译：

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对藜麦种质的大规模筛选揭示了膀胱表皮细胞和气孔模式在耐盐性中的重要作用

盐生植物中表皮膀胱细胞 (EBC) 的存在允许在这些外部结构中积累大量 Na+，远离代谢活跃的中温细胞。此外，气孔模式可能代表了植物在盐碱条件下优化其水分利用效率的主要机制。本研究旨在通过评估广泛的种质并将整体耐盐性与气孔特征和 EBC 参数的变化联系起来，探索藜麦（Chenopodium quinoa）耐盐性的品种差异。在无盐和 400 mM NaCl 条件下，在温控温室下生长 114 个种质，并测量不同的生理和解剖特征。根据定义为耐盐指数 (STI) 的相对干重，将种质分为三类（敏感、中等和耐受）。结果显示 STI 的变异性很大，表明藜麦的耐盐性存在很强的遗传变异。在盐水条件下，大多数种质的膀胱密度增加，而膀胱直径保持不变；这导致作为因变量的膀胱体积发生很大变化。盐水和非盐水条件之间的气孔密度保持不变，而气孔长度在种质中下降了 3% 到 43%。在盐水条件下，叶片 Na+ 浓度从 669 μmol/gDW 变化到 3155 μmol/gDW，除了少数种质外，在盐水条件下叶片 K+ 浓度增加。相关性分析表明，在耐盐组中，EBC 直径和 STI 之间存在显着正相关，另一方面，EBC 体积和 STI 之间存在显着正相关。这些观察结果与 EBC 在隔离外部结构中的有毒 Na+ 中的作用一致，远离细胞质。在盐敏感植物中发现 EBC 密度和直径之间存在负相关。在耐盐组中也发现了 STI 和气孔长度之间的负相关，这表明这些植物能够有效地调节气孔模式，以平衡盐水条件下的水分流失和 CO2 同化。盐敏感组和耐盐组在盐水条件下的芽中Na+浓度相同；然而，