Bioassays show that rhizobitoxine-producing strains of Bradyrhizobium japonicum excreted another phytotoxic compound into their culture fluid. This compound was purified and identified by HPLC and mass spectrometry as indole-3-acetic acid (IAA). The levels of IAA produced by the different strains of B. japonicum, for which the genotype groups have been determined with respect to the degree of b...

Current agriculture is based on external fertilizers that jeopardize soil fertility. Alternative fertilization systems might come from the use of soil-borne bacteria with plant growth enhancing ability. Here, six bacterial strains that produce varying concentrations of indole acetic acid (IAA) were tested individually and in consortia for plant growth promotion and fitness-related traits of Cic...

HARTMANN, A., M. SINGH, and W. KLINGM~~LLER. 1983. Isolation and characterization of Azospirillurn mutants, excreting high amounts of indoleacetic acid. Can. J . Microbiol. 29: 916-923. Mutants of Azospirillum brasilense Sp Cd, resistant to 5-fluorotryptophan (FT) excreted 3-indoleacetic acid (IAA), i.e., auxin, producing up to 16 pg/rnL which was 30 times greater than the wild-type level. Unde...

Soil salinity is one of the most widespread agricultural problems which reduce the field crop productivity. Salinity disturbs the hormonal balance in plants which results in poor growth. Use of plant growth promoting rhizobacteria (PGPR) is considered an economical and environment-friendly approach to combat salinity stress. This study was carried out to investigate the effect of auxin producin...

This study measured the relations between tryptophan production, the phytohormone indole-3-acetic acid (IAA) and the metabolism and accumulation of starch during synthetic mutualism between the microalgae Chlorella sorokiniana and the microalgae growth-promoting bacteria Azospirillum brasilense, created by co-immobilization in alginate beads. Experiments used two wild-type A. brasilense strains...

Abstract Many agricultural researches have been performed to improve soil productivity. Nitrogen (N) and Phosphorus (P) are essential elements which are utilized by the plants in large amounts. Phosphorus can be provided by applying chemical fertilizers. Microorganisms convert insoluble phosphate to the soluble form and some bacteria such as rhizobacteria play an important role in this proces...

A greenhouse pot experiment was carried out to evaluate the efficiency of arsenic phytoextraction by the fern Pteris vittata growing in arsenic-contaminated soil, with or without the addition of selected rhizobacteria isolated from the polluted site. The bacterial strains were selected for arsenic resistance, the ability to reduce arsenate to arsenite, and the ability to promote plant growth. P...

Azotobacter spp. are known for their ability to fix nitrogen into the soil non-symbiotically. Their activities can be enhanced through provision of optimum cultural conditions. Hence, this study aimed isolate and optimize growth (medium condtions) with a focus on pH, sucrose indole acetic acid (IAA) concentrations. The counts obtained from rhizosphere crops ranged 4.0 × 104 – 1.0 106 CFU/g. thr...

Azotobacter is a nitrogen-fixing bacteria. The growth and yield of rice (Oryza sativa L) in greenhouse were studied to examine physiological characterization efficacy isolated from the rhizosphere soil. goal was isolate that could be used as biological fertilizer. There 21 isolated, with 17 capable activity, 16 protease six IAA 13 phosphate dissolution. Each treatment carried out three times ex...

Rhizobacteria are a group of rhizosphere bacteria that lives in the soil around plant roots. The halotolerant live saline can colonize plant's presence root exudates. association rhizobacteria and roots promote growth resistance to leaf blight disease attacks rice through production IAA phytohormones at stimulate induction systemic plant. This research aims examine effect indigenous inoculation...