Effect of Pseudomonas fluorescens on someparameters of tomato growth 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 increasing drought intensity, plant height, chlorophyll a and b and total chlorophyll and other growthcharacteristics and biological yield of the plant decreased significantly. Also, during drought stress, prolinecontent and root length in Sample plants did not inoculate with bacteria. Inoculation of tomatoes with thedesired bacterial strains in all drought levels caused a significant increase in plant growth indices. Theresults showed that with increasing drought intensity, chlorophyll a and b and total chlorophyll and othergrowth characteristics and biological performance of the plant decreased significantly. Tomato inoculationwith the desired bacterial strains in all drought levels caused a significant increase in growth indices.According to the results among the strains, the W۲O strain caused a ۶% increase in root wet weight andshoot weight and in the non-stress level, and the WB۱-۷ strain caused a ۲۲% increase in total chlorophylland a ۱۹% increase in chlorophyll b and a ۲۶% increase in chlorophyll a in the stress level. Mild ormoderate. Also, according to the results among the strains, Pseudomonas fluorescent B۴-۶ increased thenumber of flowers by ۲۰.۱۷% at the level of no drought stress (۱۰۰ percent irrigation of crop capacity)compared to the Sample at the same level of drought. Greenhouse results showed that bacterial strainsincreased tomato growth indices and decreased water stress effects.It should be noted that the rate ofincrease in growth indices varied depending on the type of bacterial strain.