Arbuscular mycorrhizal fungi (AMF) and biochar have potential applications in agriculture and ecological restoration. However, the effects of AMF combined with biochar on the bioenergy quality of plants under saline-alkali stress have not been thoroughly studied. In this study, we examined the effects of Rhizophagus irregularis (Ri) and biochar application, individually or in combination, on the growth, osmoregulation, ion uptake, and expression of energy quality-related genes in switchgrass under saline-alkali stress. The results showed: (1) The biomass of switchgrass in the BR treatment group increased by 35.50 % and 39.71 % compared with the BC and Ri treatment groups, respectively; (2) Ri combined with biochar increased the activity of antioxidant enzymes and the accumulation of osmoregulatory substances, and influenced plant hormone synthesis; (3) The combined treatment significantly increased the contents of K+, Ca2+, and Mg2+ in leaves and roots, reduced the contents of Na+, and maintained high K+/Na+, Ca2+/Na+, and Mg2+/Na+ ratios; (4) The expression levels of stress response, reactive oxygen scavenging, ion transport, and cellulose biosynthesis genes in leaves and roots of switchgrass were the highest in the BR treatment; (5) The cellulose, hemicellulose, and calorific value of switchgrass in the BR treatment group reached maximum values of 29.2 %, 29.1 %, and 17.6 MJ/kg, respectively. Our findings demonstrate that Ri combined with biochar can enhance the saline-alkali tolerance of switchgrass, improve plant energy quality, and provide a new approach for increasing the planting area and improving the quality of energy plants.

中文翻译：

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Rhizophagus irregularis 与生物炭合用可通过渗透调节和基因表达提高柳枝稷的耐盐碱性和能量质量


丛枝菌根真菌 （AMF） 和生物炭在农业和生态恢复方面具有潜在的应用。然而，AMF 与生物炭联合对盐碱胁迫下植物生物能源质量的影响尚未得到深入研究。在这项研究中，我们研究了不规则根瘤菌 （Ri） 和生物炭单独或联合施用对盐碱胁迫下柳枝稷能量质量相关基因的生长、渗透调节、离子摄取和表达的影响。结果表明：（1）BR处理组柳枝稷生物量较BC和Ri处理组分别增加了35.50 %和39.71 %;（2） Ri 与生物炭结合提高了抗氧化酶的活性和渗透调节物质的积累，并影响了植物激素的合成;（3）联合处理显著提高叶片和根系中K+、Ca2+、Mg2+含量，降低Na+含量，保持较高的K+/Na+、Ca2+/Na+和Mg2+/Na+比值;（4） 柳枝稷叶片和根中胁迫响应、活性氧清除、离子转运和纤维素生物合成基因的表达水平在 BR 处理中最高;（5） BR 处理组柳枝稷的纤维素、半纤维素和热值分别达到最大值 29.2 % 、 29.1 % 和 17.6 MJ/kg。我们的研究结果表明，Ri 与生物炭结合可以增强柳枝稷的耐盐碱性，提高植物能量质量，为增加种植面积和提高能量植物的质量提供了一种新的途径。