Plant growth‐altering effects of Azospirillum brasilense and Bacillus C–11–25 on two wheat cultivars

Abstract

The effect of Azospirillum brasilense Cd, Bacillus C–11–25, indole acetic acid, gibberellic acid and cytokinin on plant growth characteristics of two wheat (Triticum aestivum L. emend Thell) cultivars was studied under laboratory and greenhouse conditions. Responses of wheat plants to bacterial inoculation were similar to those caused by the addition of gibberellic acid in growth pouches. Chester and Fielder wheat varieties differed in responses to the bacteria and hormone additions. When added to growth pouches, bacterial culture filtrates and dead bacterial cells caused plant growth responses similar to those caused by the addition of live cells. Bacteria and hormone additions resulted in increased permeability of Fielder wheat to 15Nlabelled nitrate, and decreased nitrate permeability of Chester wheat. Bacterial inoculation of soil in pots caused 15N isotope dilution in Fielder but not in Chester wheat. Hormone addition to pots caused isotope dilution in Chester wheat. It appeared that genetic differences between cultivars affected plant growth responses. The accuracy of estimates of N2 fixation by associative bacteria based on 15N isotope dilution calculations may be reduced if control plants differ in plant response to these bacteria.

Agricultural uses of plant biostimulants

“…and Bacillus spp. has been implicated in the increased 15 N uptake observed after inoculation of wheat roots (Kucey 1988).…”

Physiological and genetic analysis of root responsiveness to auxin-producing plant growth-promoting bacteria in common bean (Phaseolus vulgaris L.)

“…The outcome on the plant side usually is a function of the amount of IAA that is available to the plant and the sensitivity of the plant tissue to changes in IAA concentration. Studies on the interaction between auxin-producing bacterial strains and wheat (Kucey 1988), blackcurrant and sourcherry softwood (Dubeikovsky et al 1993) highlight the potential of selecting cultivars with improved root responsiveness to auxin-producing bacteria. However, not much is known on the genetic basis that causes natural variation in root responsiveness to exogenous auxin and auxin-producing PGPR across genotypes.…”

Identification of Gibberellins A1, A3, and Iso-A3 in Cultures of Azospirillum lipoferum

“…Most attention has been focused on auxin production (3, 4); however, GAs may also be involved since inoculation of wheat with Azospirillum produces an increase in '5N uptake, and this effect can be mimicked by application of GA3 to the wheat plant (7). Gibberellins have been identified from cultures of Rhizobium phaseoli (1).…”