Three species of arbuscular mycorrhizal fungi confer different levels of resistance to water stress in Spinacia oleracea L.

Arbuscular mycorrhizal fungi (AMF) are applied in agriculture to improve plant nutrition and confer better resistance to biotic and abiotic stresses. Spinacia oleracea L. is an economically important herbaceous crop characterized by limited tolerance to water stress. We compared the effects of three species of AMF belonging to the genus Glomus on gas exchange rates, growth and yield of spinach plants exposed to acute and prolonged water stress. Inoculated plants always gave better results than control (non-inoculated), stressed ones, being G. clarum the species that provided the significantly best effects and G. monosporum the less remarkable ones. Mycorrhizal inoculation is a valid tool to provide water stress resistance to horticultural crops, and experimental comparisons among different mycorrhizal strains can help to optimize the effect through the identification of specific associations.