Azospirillum brasilense mitigates anatomical alterations produced by salt stress in jojoba in vitro plants

Abstract

Jojoba, Simmondsia chinensis (Link) Schneider, is a slow-growing woody perennial shrub, whose production can be limited by soil salinity. Based on the fact that alterations of salinity stress can be reduced by biofertilization, the aim of this work was to study the effects of salinity and Azospirillum brasilense inoculation on the probable structural characteristics of leaves, stems, and roots of jojoba plants grown in vitro by light and scanning electron microscopy. Salt stress induces changes in anatomical characteristics of jojoba in vitro such as increment in mesophyll thickness on leaves, and increases in the cortex, pith, and xylem vessel diameters on stems. Cell density decreased in leaf and stem, and increased in roots. Azospirillum brasilense inoculations mitigated leaf succulence and prevent the root anatomical alterations caused by salinity displaying leaf mesophyll and chlorenchyma thickness, root diameter, cortex thickness, and vascular bundle diameter similar values to control plants in some treatments. Also improved the anatomical characteristic of the stem and increment the xylem vessels ratio between stem and root. The anatomical changes induced by A. brasilense could protect jojoba plants from the detrimental effects of saline stress and explain the higher tolerance to salinity of inoculated plants.