Salinity is an increasing problem in coastal areas affected by saltwater intrusion, with deleterious effects on tree health and forest growth. Ectomycorrhizal (ECM) fungi may improve the salinity tolerance of host trees, but the impact of external potassium (K+) availability on these effects is still unclear. Here, we performed several experiments with the ECM fungus Paxillus ammoniavirescens and loblolly pine (Pinus taeda L.) in axenic and symbiotic conditions at limited or sufficient K+ and increasing sodium (Na+) concentrations. Growth rate, biomass, nutrient content, and K+ transporter expression levels were recorded for the fungus, and the colonization rate, root development parameters, biomass, and shoot nutrient accumulation were determined for mycorrhizal and non‐mycorrhizal plants. P. ammoniavirescens was tolerant to high salinity, although growth and nutrient concentrations varied with K+ availability and increasing Na+ exposure. While loblolly pine root growth and development decreased with increasing salinity, ECM colonization was unaffected by pine response to salinity. The mycorrhizal influence on loblolly pine salinity response was strongly dependent on external K+ availability. This study reveals that P. ammoniavirescens can reduce Na+ accumulation of salt‐exposed loblolly pine, but this effect depends on external K+ availability.

中文翻译：

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外生菌根真菌氨绿芽孢杆菌影响盐度对火炬松响应钾有效性的影响

在受盐水入侵影响的沿海地区，盐度是一个日益严重的问题，对树木健康和森林生长产生有害影响。外生菌根（ECM）真菌可能会提高寄主树的耐盐性，但外部钾（K）的影响+）这些影响的可用性仍不清楚。在这里，我们用 ECM 真菌进行了多项实验氨绿芽孢杆菌和火炬松（火炬松L.) 在有限或足够 K 的无菌和共生条件下+并增加钠（Na+）浓度。生长率、生物量、养分含量和钾+记录真菌的转运蛋白表达水平，并测定菌根和非菌根植物的定殖率、根发育参数、生物量和芽养分积累。氨绿假单胞菌尽管生长和养分浓度随 K 的变化而变化，但仍能耐受高盐度+可用性和增加Na+接触。虽然火炬松根系的生长和发育随着盐度的增加而减少，但 ECM 定殖不受松树对盐度的反应的影响。菌根对火炬松盐度响应的影响强烈依赖于外部 K+可用性。这项研究表明氨绿假单胞菌可以减少Na+盐暴露火炬松的积累，但这种影响取决于外部钾+可用性。