Azospirillum spp., a Dynamic Soil Bacterium Favourable to Vegetable Crop Production

摘要

The soil is not merely an inert support for anchoring the plant. Its complexity and dynamics determine the way plants will grow and develop. In these processes, the root and its interaction with the different abiotic and biotic soil components represent a key point in the acquisition of water and essential nutrients. However, anthropogenic effects on the environment - including soil and water deterioration and contamination - could alter these relationships. In addition to these, vegetable productionpresents diverse problems, which could be mitigated by the use of plant-growth promoting microorganisms (PGPMs). On the soil, PGPMs could contribute to solubilize and/or to acquire essential minerals, making scarce nutrients more available to the plant.On the host, they stimulate several physiological changes that could lead to a better growth and to a plant more tolerant to abiotic stresses. Amongst PGPMs, Azospirillum is one of the most studied genera. Even though it colonizes different plant species in an ample variety of soils, its favourable effects on vegetable germination, emergence and growth, have not been thoroughly studied. This review describes the beneficial effects PGPM inoculation could have on vegetables growing either under normal orstressful conditions, with an emphasis on the use of Azospirillum. It also focuses on the recent advances on Azospirillum-plant interactions and the bacterial mechanisms of plant growth promotion.