Browsing by Author "Msumali, G.P."

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Bean Nodulation Patterns in Soils of Different Texture at Morogoro, Tanzania
(1998) Msumali, G.P.; Judith, A.K.
system in three soils of varying texture and % recovery of rhizobia I cells immediately after inoculation into such soils. Effects of inoculation methods (seed pelleting versus soil inoculation) on nodulation and plant growth were investigated in the three soils using a serologically- marked Rhizobium strain (ClAT 899) which was subsequently monitored in the nodules by the enzyme-linked immunosorbent assay (ELISA) technique. When the major soil chemical factors affecting nodulation were standardized, bean nodulation patterns continued to be closely related to soil texture, being higher in the sandy and loamy soils than in the fine-textured clay. Soil inoculation consistently gave better nodulation than seed pelleting.According to the ELISA procedure however, percent nodule occupancy by ClAT 899 showed patterns completely the opposite of the nodulation trends outlined above, being 100% in the clay but only 10% in the sandy soil. Thus, nodulation success by the inoculum was total in the clay but only dismal in the sandy soil. The unexpected discrepancy between inoculum success on the one hand and nodulation plus plant growth response on the other, is discussed.
Bean nodulation patterns in soils of different texture at Morogoro, Tanzania
(1998) Msumali, G.P.; Judith, A.K.
This study was designed to examine the, relationship between nodulation in a bean-Rhizobium system in three soils of varying texture and % recovery of rhizobia I cells immediately after inoculation into such soils. Effects of inoculation methods (seed pelleting versus soil inoculation) on nodulation and plant growth were investigated in the three soils using a serologically- marked Rhizobium strain (ClAT 899) which was subsequently monitored in the nodules by the enzyme-linked immunosorbent assay (ELISA) technique. When the major soil chemical factors affecting nodulation were standardized, bean nodulation patterns continued to be closely related to soil texture, being higher in the sandy and loamy soils than in the fine-textured clay. Soil inoculation consistently gave better nodulation than seed pelleting.According to the ELISA procedure however, percent nodule occupancy by ClAT 899 showed patterns completely the opposite of the nodulation trends outlined above, being 100% in the clay but only 10% in the sandy soil. Thus, nodulation success by the inoculum was total in the clay but only dismal in the sandy soil. The unexpected discrepancy between inoculum success on the one hand and nodulation plus plant growth response on the other, is discussed.
Loss of Desiccation Resistance following the artificial cultivation of cowpea bradyhizobia isolated from previously - desiccated soil
(2002) Msumali, G.P.
Soil kept in a desiccated condition (6% moisture content, equivalent to 38.6 Mpa tension) for 2 years was found to contain 300. viable cells of cowpea bradyrhizobia, per gram of soil, contrary to the general consensus that rhizobia are highly sensitive to desiccation. Two strains of the native bradyrhizobial population were isolated via host legume infection. From each of the strains, doubly-labelled, antibiotic resistant mutants were developed in order to follow-up their survival when re-introduced into natural (non-sterile) soil. The double labeling was achieved by selection for sequential resistance to high concentrations (500 mg l) of the antibiotics streptomycin and spectinomycin. The antibiotic resistant strains were then stored in yeast-extract mannitol agar for 3 months at 4 oC. The survival ability of the antibiotic-resistant strains was then studied over a 6-week period in the same soil of their origin under conditions of favourable moisture (field capacity) or under slaw desiccation to the mosture level at which the same strains had previously survived for 2 years. This evaluation was undertaken both in previously sterilized soil and in natural (non-sterile) soil. Results of this study indicated that both strains generally survived poorly under conditions of soil desiccation. In fact the population of one of the strains declined to extinction within 6 weeks even in previously sterilized soil in which all probable antagonistic biotic factors were precluded. It was concluded from the findings of this study that the common practice of artificial cultivation and storage rhizobia in agar culture media and other forms of laboratory manipulations of the micro-organisms was partially implicated for their loss in survival ability under desiccation. It is therefore suggested that superior strains of rhizobia or bradyrhizobia intended for longer term storage for commercial inoculant production, be maintained in sterile carriers other than in agar media.