Immobilized microalgae and bacteria improve salt tolerance of tomato seedlings grown hydroponically

摘要

Wild-type Azospirillum brasilense Cd, mutant Azospirillum brasilense Cd transformed bacteria with a plasmid harboring a trehalose biosynthesis gene fusion from Saccharomyces cerevisiae, and Chlorella vulgaris were used as immobilized inoculants for tomato seedlings growing in hydroponic media prepared with different proportions of NaCl. Stem and main root length, number and length of leaves, and secondary roots of seedlings were measured and compared between treatments as indicator of biomass production. A positive effect in tomato seedlings was observed when co-cultured with Azospirillum (transformed and wild type) and C. vulgaris. Those seedlings growing with wild-type Azospirillum and Chlorella showed longer stems for lower salinities. Conversely, longer stems were observed when transformed Azospirillum and C. vulgaris were used as inoculant in the highest salinity tested (250 mM NaCl).