In this study the effects of Azispirilium brasilense, Pseudomonas florescens and Azotobacter chroococcum bacteria on Aloe vera planted in greenhouse conditions were studied. The study was conducted based on completely randomized blocks design with three replication and eight treatments. The treatments included: 1-Bacteria inoculation using Azispirilium brasilense bacterium 2- Bacteria inoculation using Pseudomonas florescens bacterium 3- Bacteria inoculation using Azotobacter chroococcum bacterium 4,5,6- Bacteria inoculation using a mixture of two bacteria 7- Bacteria inoculation using a mixture of all three bacteria and 8- a control. The statistical analysis suggested that plant growth stimulant bacteria tested in this research had significant effect on the increase of growth traits specially the gel weight of fully grown leaf, the bulk and mass of fully grown leaf, the average width of the leaves on a bush, and vitamin C, but they did not have any effect on the weight of the root and the length of the bush. The most significant effect was reported to be from Aztobacter bacterium. The findings of the research show the high potential of applying growth stimulant bacteria for improving both quantitative and qualitative aspects of Aloe vera production.
