The early seedling stage is highly susceptible to various abiotic stresses. is an ornamental plant with excellent abiotic stress tolerance, and widely distributed in the northeast of China. However, the mechanism of its physiological and transcriptional resistance under different abiotic stresses is still unclear. The results showed that the leaves of adapted to saline-alkali and drought environments by increasing the density of wax and glandular hairs, reducing the stomatal length, width and opening, and the leaf cells completely ruptured and a large number of organelles disintegrated under alkali stress. With the increasing stress concentration, the chlorophyll content and dry weight reduced under the three stresses, which was related to the broken chloroplasts of such conditions. In addition, the balance of Na and K was disturbed, and the increase of APX and SOD activity was the strategy to maintain the balance of reactive oxygen species and weaken the degree of membrane lipid peroxidation under three stresses. And alkali stress had the most significant effect on above changes. Moreover, Transcriptional sequencing revealed the alkali stress group had the highest number of differential expressed genes (DEGs) compared to the CK among three stresses, and a significant down-regulation of DEGs related to membrane systems under three stresses. In addition, alkali stress resulted in large number of up-regulation of DEGs associated with light repair processes and down-regulation of DEGs in ribosomal pathway with R proteins involving in regulating leaf phenotype and ultrastructure, which also echoed the overall physiological findings. Together, the adaptation mechanisms of three stresses were different in seedlings with higher tolerance of salt stress, and extremely sensibility to alkali stress.

中文翻译：

---

均匀水势下大麦幼苗响应盐、碱和干旱胁迫的生理和转录组分析

幼苗早期极易受到各种非生物胁迫的影响。是一种具有优良非生物胁迫耐受性的观赏植物，广泛分布于我国东北地区。然而，其在不同非生物胁迫下的生理和转录抗性机制仍不清楚。结果表明，叶片在碱胁迫下通过增加蜡质和腺毛密度，减小气孔长度、宽度和开口度来适应盐碱和干旱环境，叶细胞完全破裂，大量细胞器解体。 。随着胁迫浓度的增加，三种胁迫下的叶绿素含量和干重均减少，这与该条件下叶绿体的破碎有关。此外，Na、K平衡被扰乱，APX和SOD活性的增加是三种胁迫下维持活性氧平衡、减弱膜脂过氧化程度的策略。其中碱胁迫对上述变化影响最为显着。此外，转录测序显示，在三种胁迫下，与CK相比，碱胁迫组的差异表达基因（DEG）数量最多，并且与膜系统相关的DEG在三种胁迫下显着下调。此外，碱胁迫导致与光修复过程相关的DEG大量上调，以及参与调节叶片表型和超微结构的R蛋白核糖体途径中DEG的大量下调，这也与整体生理学发现相呼应。综合来看，幼苗对三种胁迫的适应机制不同，对盐胁迫的耐受性较高，而对碱胁迫极其敏感。