Background and aims

Plants can minimize the adverse effects of salinity by modifying morphological and anatomical features. Previous studies showed that endophytic Epichloë bromicola play an important role in improving wild barley (Hordeum brevisubulatum) salinity tolerance. The aim of this work is to understand whether Epichloë endophyte affects the anatomical structures of host H. brevisubulatum under salinity environments.

Methods

Seedlings of E. bromicola infected (E+) and E. bromicola free (E-) H. brevisubulatum were treated with different NaCl concentrations, with the control seedlings being grown without NaCl. Anatomical structures of roots, stems and leaves were observed by making paraffin sections with double staining dehydration methods (safranin and fast green).

Results

NaCl treatments significantly affected the anatomical structure of H. brevisubulatum. Vascular tissue area throughout the leaf, stem and root decreased as the NaCl concentration increased. Thickness of epidermis in stems and leaves, and the cortex in roots also decreased with salt level increases. Endodermis thickness, epidermis thickness and stele area in roots were increased under salinity stress. The presence of Epichloë endophyte regulated some anatomical structure modifications. Epichloë infection was associated with significant higher conducting tissues (including leaf xylem, leaf phloem, stem vascular bundles, stem xylem vessels and root meta-xylem area). The increased thickness of leaf veins, epidermis in stems, cortex and endodermis in roots were also associated with Epichloë endophyte infection under NaCl stress.

Conclusions

The presence of Epichloë endophyte ameliorated adverse effects of salinity on H. brevisubulatum. We observed specific changes of anatomical structures that may help in inhibiting water loss and inhibiting decrease of transport capacity for better conduction of water, nutrients, photosynthates and re-translocation of assimilates to suppress negative effects of salinity and enhance the tolerance of H. brevisubulatum to salt stress.

中文翻译：

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真菌内生真菌Epichloëbromicola感染调节解剖学变化，以说明野生大麦（Hordeum brevisubulatum）的盐胁迫耐受性

背景和目标

植物可以通过改变形态和解剖特征来最小化盐度的不利影响。先前的研究表明，内生的溴化埃希氏菌在提高野生大麦（大麦（Hordeum brevisubulatum））的耐盐性中起重要作用。这项工作的目的是了解盐渍环境下内生附生植物是否会影响寄主H. brevisubulatum的解剖结构。

方法

幼苗E. bromicola感染（E +）和E. bromicola免费（E-）野大麦分别用不同浓度的NaCl处理，用不含NaCl中生长的对照幼苗。用双重染色脱水法（藏红素和速溶绿）制作石蜡切片，观察根，茎和叶的解剖结构。

结果

NaCl处理显着影响短螺旋体的解剖结构。随着NaCl浓度的增加，整个叶，茎和根的血管组织面积减少。茎和叶的表皮厚度以及根部的皮层也随着盐含量的增加而降低。在盐分胁迫下，根中的内胚层厚度，表皮厚度和石碑面积均增加。Epichloë内生菌的存在调节了一些解剖结构的变化。Epichloë感染与明显较高的传导组织（包括叶木质部，叶片韧皮部，茎维管束，茎木质部血管和根间木质部区域）有关。在NaCl胁迫下，叶脉，茎表皮，根部皮质和内胚层厚度的增加也与Epichloë内生菌感染有关。

结论

内生真菌Epichloë的存在改善了盐度对短螺旋藻的不利影响。我们观察到特定的解剖结构变化，这可能有助于抑制水分流失并抑制运输能力的下降，从而更好地传导水，养分，光合产物和同化物的重新转运，从而抑制盐分的负面影响并增强短短螺旋体对水的耐受性。盐胁迫。