Salt stress is one of the major abiotic stress, impedes plant photosynthetic processes, changes root architecture to impact leaf water status, and reduces potassium uptake and K⁺/Na⁺ ratio. Arbuscular mycorrhizal (AM) fungus and extra potassium promote plants tolerance of salt stress, respectively. However, little is known about the combined influence of AM fungus and extra potassium under salt stress. In current study, we analyzed the effects of AM fungus (Rhizophagus irregularis), potassium application (0, 1.6, and 6.4 mM K⁺), and salt stress (0 and 100 mM NaCl) on photosynthesis, leaf water status, root architecture, concentrations of Na⁺ and K⁺, shoot/root Na⁺, K⁺/Na⁺ homeostasis, and the relative expression of genes related to K⁺ uptake and transport (LbHAK, LbKT1, and LbSKOR) of Lycium barbarum. Under salt stress, inoculation of R. irregularis and application of potassium increased the net photosynthetic rate and stomatal conductance and reduced the intercellular CO₂ concentration to improve photosynthesis. Inoculation of R. irregularis and application of potassium increased leaf relative water content and reduced water saturation deficit. Inoculation of R. irregularis and potassium application also modified root architecture, particularly in terms of root elongation and SRL reduction. Moreover, they increased K⁺ concentration, but evidently reduced Na⁺ transport to shoot. Regardless of salinity, AM plants had a significant decrease in shoot/root Na⁺ ratio compared with NM plants under each potassium condition. Additionally, R. irregularis and extra potassium upregulated the relative expressions of LbHAK, LbKT1, and LbSKOR, which are involved in K⁺/Na⁺ homeostasis. This study suggests that the beneficial effects of R. irregularis and extra potassium on photosynthetic capacity, root architecture, and K⁺/Na⁺ homeostasis improved the growth and salt tolerance of L. barbarum under salt stress.

盐胁迫是主要的非生物胁迫之一，会阻碍植物的光合作用过程，改变根系结构以影响叶片水分状况，并降低钾吸收和 K ⁺ /Na ⁺比率。丛枝菌根 (AM) 真菌和额外的钾分别促进植物对盐胁迫的耐受性。然而，人们对盐胁迫下 AM 真菌和额外钾的综合影响知之甚少。在当前的研究中，我们分析了 AM 真菌（不规则根霉）、钾肥（0、1.6和 6.4 mM K ⁺）和盐胁迫（0 和 100 mM NaCl）对光合作用、叶片水分状况、根系结构、 Na ⁺和 K ^{+ 的}浓度，地上部/根部 Na ⁺、K ⁺ /Na ⁺稳态，以及枸杞K ⁺吸收和转运相关基因（LbHAK、LbKT1和LbSKOR）的相对表达。在盐胁迫下，接种不规则草和钾肥可提高净光合速率和气孔导度，降低细胞间CO ₂浓度，促进光合作用。接种不规则罗非鱼和施用钾肥增加了叶片的相对含水量并减少了水分饱和度不足。接种不规则罗非鱼施钾还改变了根系结构，特别是在根系伸长和 SRL 降低方面。此外，它们增加了 K ⁺浓度，但明显减少了 Na ⁺向芽的转运。无论盐度如何，在每种钾条件下，AM 植物的地上部/根 Na ⁺比与 NM 植物相比显着降低。此外，不规则红血球藻和额外的钾离子上调了LbHAK、LbKT1和LbSKOR的相对表达，它们与 K ⁺ /Na ⁺稳态有关。这项研究表明，不规则木耳的有益作用和额外的钾对光合能力、根系结构和 K ⁺ /Na ⁺稳态的影响改善了盐胁迫下L. barbarum的生长和耐盐性。