For the purpose of examining the correlations, if any, between the root and shoot growths of three Citrus species and their rhizosphere microflora, studies were made with 6-year-old plants in the Annamalai University Experimental Orchard. The rhizosphere population was analyzed quantitatively. Bacteria were about 40 to 90 times, actinomycetes 2 to 6 times, and fungi 3 to 6 times more abundant in the rhizosphere than in the soil, in rhizosphere populations there was no significant difference between the three Citrus species. Comparisons of populations on the growing and non-growing roots of the three Citrus species revealed that the growing roots harbored 2 to 3 times more bacteria and actinomycetes than the non-growing roots. There was only slight increase in the fungal population in the rhizosphere of the citrus variety Pummelo but not in the other two varieties.
The metabolism of the fungicide Dexon (p-dimethylaminobenzenediazo sodium sulfonate) by a soil bacterium is reported for the first time. The organism which is capable of using Dexon only by a co-metabolic process was obtained by enrichment culture and was identified as Pseudomonas fragi. The first metabolic product of Dexon was identified as N, N-dimethyl-p-phenylenediamine. The presence of an enzyme, p-dimethylaminobenzenediazo sodium sulfonate reductase, capable of reducing Dexon to N, N-dimethyl-p-phenylenediamine has been demonstrated in the cell-free extracts of the organism. The enzyme is found to be in the soluble fraction and requires dithiothreitol as a reductant.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.