Effect of Pseudomonas fluorescens on Tomatogrowth under drought stress

Drought stress is one of the main factors reducing crop yield. One of the biological ways to reduce thenegative effects of drought stress is to use plant growth promoting bacteria. In this study, the effect offluorescent Pseudomonas on tomato growth indices under drought stress was evaluated. The strains werefirst tested for drought tolerance in medium containing polyethylene glycol ۶۰۰۰ (PEG). Then their effecton the growth characteristics of tomato cultivar Sunseed under drought stress in greenhouse conditions wasinvestigated based on a randomized complete block design with three replications The results showed thatwith the increase in drought intensity, the height of the plant and other growth characteristics and thebiological performance of the plant decreased significantly. Also, during drought stress, the amount ofproline and root length increased in Sample plants without inoculation with bacteria. Tomatoes with thedesired bacterial strains in all dry levels caused a significant increase in plant growth indices, according tothe results among the strains, the W۲O strain caused a ۲۱% increase in root volume at the non-stressedlevel, and the B۴-۶ strain caused a ۲۶% increase in root volume. The weight percentage of a single fruit inthe non-stress level, and the W۲O strain caused a ۳۰% increase in the dissolved solids in the non-stressedlevel compared to the Sample at the same drying level. Also, the WB۱-۷ strain increased the stability ofthe cell membrane by ۹.۲۸% in the non-stressed level compared to the Sample in The same level .Greenhouse results showed that bacterial strains increased tomato growth indices and decreased waterstress effects. It should be noted that the rate of increase in growth indices varied depending on the type ofbacterial strain.