Arbuscular mycorrhizal fungi (AMF) are soilborne microorganisms that establish a mutualistic symbiotic association with most of land plants. To investigate the effects of AMF symbiosis under different water status conditions, we grew AMF-inoculated and non-inoculated tomato plants in the greenhouse under two irrigation regimes, 70% and 30% of growth-substrate water holding capacity. Two different AMF inoculation strains, Funneliformis mosseae and Rhizophagus irregularis, were applied as single inocula. AMF colonization significantly enhanced plant vegetative growth by 40% and 50–60%, under normal and reduced irrigation respectively. In the presence of the AMF, phosphorous concentrations in the leaves were increased under both watering regimes while K, Ca, Mg, Zn, and Mn were also increased under limited watering to levels similar to those of non-stressed plants. Transpiration and stomatal conductance increased by an average 80% and 65% respectively in the presence of the AMF under full watering, but were kept stable and coupled to reduced leaf area-to-leaf biomass ratios and to increased metabolic water use efficiency under limited irrigation. This indicates a different mode of action induced by AMF colonizers, prioritizing water conservation in tomato plants under drought stress.

丛枝菌根真菌 (AMF) 是土传微生物，与大多数陆生植物建立互惠共生关系。为了研究 AMF 共生在不同水分状况条件下的影响，我们在温室中在两种灌溉制度下分别种植了接种 AMF 和未接种 AMF 的番茄植株，分别为 70% 和 30% 的生长基质持水量。两种不同的 AMF 接种菌株，Funneliformis mosseae和Rhizophagus normis，作为单一接种应用。在正常灌溉和减少灌溉下，AMF 定植分别显着增强了植物营养生长 40% 和 50-60%。在 AMF 存在的情况下，两种浇水方式下叶片中的磷浓度都增加，而 K、Ca、Mg、Zn 和 Mn 在有限浇水下也增加到与非胁迫植物相似的水平。在充分浇水的情况下，在 AMF 存在的情况下，蒸腾作用和气孔导度分别增加了平均 80% 和 65%，但保持稳定并与叶面积与叶生物量比的降低以及有限灌溉下代谢水分利用效率的增加相结合. 这表明 AMF 定植者诱导的不同作用模式，优先考虑干旱胁迫下番茄植物的水分保持。