BACKGROUND Zinc is an essential micronutrient used in the form of zinc sulfate in fertilizers in the agriculture production system. Nitrogen-fixing microorganisms are also of considerable value in promoting soil fertility. OBJECTIVES This study aimed to investigate the degree of sensitivity to varying concentrations of zinc, in the form of ZnSO4, in different strains of Azotobacter chroococcu...

A PREVIOuS report [Wyss & Wilson, 1941] demonstrated that B2 inhibits fixation of N2 by Azotobacter. Because of the apparent uniqueness of this type of inhibition, such a demonstration furnishes strong evidence that in the symbiotic and free-living N2 fixation processes the mechanism of fixation is very similar if not identical. Further studies described in this paper provide additional support...

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...

in order to evaluate the response of quantitative and qualitative characteristics of the isabgol (plantago ovata frosk.) medicinal plant to separate and combined application of urea and biofertilizer an experiment was conducted in a randomized complete block design at the research farm of shahrekord university in 2011. the experimental treatments consisted of control (no urea and biological fer...

L6hnis and Smith (1923) pointed out that not less than seven different morphological types can be developed and stabilized from Azotobacter cultures. This extreme transmutation of cells has been questioned by subsequent investigators (Lewis, 1937, 1941). Nevertheless, peculiar morphological phases do occur in Azotobacter cultures and no satisfactory explanation has been given as to their functi...