الفهرس | Only 14 pages are availabe for public view |
Abstract A survey study was carried out to evaluate the influence of environmental factors (atmospheric temperature, relative humidity, wind speed and dew point) on the densities of microorganisms (fungi, yeast, azotobacters, azospirilla, N 2-fixing bacilli and total microbes) in the phyllosphere of 23 wild desert medicinal plants grown. in different desettic locations of Egypt. Amongst 23 azotobacters and 13 azospirilla, selection and identification of the most active Nrfixers as indicated by their Nrase activity and the most active producers of growth promoting substances namely IAA, IBA, cytokinins and gibberellins, which were qualitatively and quantitatively determined in microbial cultures were carried out by using thin layer and gas-liquid chromatography techniques. The most active 6 diazotrophic strains (4 strains of Azotobacter chroococcum and 2 strains of Azospirillum sp.) were used in a mixture to inoculate the phyllosphere of Datura innoxia plants in the presence of graded levels of inorganic N-fertilizer (0, V4, Yz, 3/4 and the full N-dose ). The effect of inoculation and inorganic N-fertilization on the growth of Datura plants were periodically estimated during 180 days after cultivation. Alkaloid content was determined at the end of experiment. It was generally clear that inoculating the phyllosphere of the growing plants in the presence of the full dose of inorganic N fettilizer followed in a descending order by the application of% the dose (without significant differences) showed the highest growth and alkaloid content of Datura plants. |