Azospirillum spp

Establishment of inoculated Azospirillum spp. in the rhizosphere and in roots of field grown wheat and sorghum. Plant Soil 90 35-46. 

The presence of microorganisms in the rhizosphere has been shown to increa.se root exudation (58,61-65). This stimulation of exudation has been shown to occur in the pre.sence of free-living bacteria such as Azospirillum spp. and Azotobacter spp. (66,67) and in the presence of symbiotic organisms such as mycorrhizae (68,69). Increased root exudation has also been shown to be species-specific for example Meharg and Killham (65) found that metabolites produced by Pseudomonas aeru/ inosa stimulated a 12-fold increase in C-labeled exudates by perennial ryegrass. However, under the same conditions, metabolites from an Arthro-bacter species had no effect on root exudation. 

Azospirillum spp. Spartina roots Zostera roots Seawater... 

Condensation products of DHB (which usually is found also in the fermentation broth) with amino acids were reported, viz. with glycine ixom Bacillus subtilis (164) named subsequently itoic acid (282) with serine from Escherichia coli (261) and Klebsiella oxytoca (196) with threonine from Klebsiella oxytoca (196) and Rhizobium spp. (275, 327) with arginine from Pseudomonas stutzeri (62) with glycine and threonine from Rhizobium sp. (240) with threonine and lysine as well as with leucine and lysine from Azospirillum lipoferum (312, 320). In most cases the isolate (sometimes designated as being a siderophore) was hydrolyzed and the constituents were determined by paper chromatography. The relative amounts of the constituents, the chiralities of the amino acids and the molecular mass of the isolate have not been determined. Hence it is not known whether condensation products of the enterobactin type exist. 

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