Effect of Raw Pectin Amendment on The Survival and Proliferation of Azospirillum in Non-Sterile Soil

Abstract

Abstract TWO STRAINS of plant growth-promoting (PGPR) bacterium Azospirillum were isolated as endophytes from roots of wheat seedlings grown in the spermosphere model that was inoculated with aliquots of two rhizosphere soil samples. Azospirillum isolate 3Re was recovered after inoculation with Sisamum irio rhizosphere soil and the other isolate (1Rr) was recovered after inoculation with rhizosphere soil from Faculty of Science's botanical garden at Minia University that was planted with Allium cepa. One of the physiological studies on those Azospirillum strains exhibited that they have a pectinolytic activity. The present study aims to evaluate the effect of these locally isolated Azospirilla inoculation into a raw pectin amended soil, cultivated with Zea mays seedlings, on their population densities in rhizosphere and free soils and how far this could affect some of Zea mays growth parameters. The investigation was carried out in pot experiments using non-sterile clay soil. The most important observation in this study was that the viable Azospirillum counts in raw pectin amended free soil is equal to that of the un-amended rhizosphere soil which could indicate that the most valuable nutrient that Azospirillum could gain from root exudates is the utilizable carbon, and when it supplied to the free soil, the population number reaches that of the rhizosphere soil without the need to any other supplementation.