Rhizobium leguminosarum biovar viceae strain TAL 1236 growing on
different organic phosphorus compounds as sources of phosphate exhibited phosphatase
activities. The strain was able to produce both acid and alkaline phosphatases. However, its
ability to produce alkaline phosphatase was much higher. When cellular phosphate fell to
0.115% of cell protein, cellular and extracellular phosphatase activities were promoted.
Mg2+, Co2+ and Ca2+ enhanced slightly the activity of alkaline phosphatase more than acid
phosphatase. However, Mn2 + and Fe2+ activated acid phosphatase rather than alkaline
phosphatase. It may be concluded that Rh. leguminosarum plays an important role in the
release of phosphorus from its organic compounds through the action of phosphatases which
can be slightly activated by a range of cations.

Soil salinity is a major limitation to legume production. We evaluated specific soybean [Glycine max (L.) Merr.] genotypes to identify a salt-tolerant soybean-Bradyrhizobium system, and to determine by grafting experiments if the scion or the root was responsible for salt tolerance. The effects of three levels of salinity (0, 30, and 60 mM NaCl) on nitrogenase activity (acetylene reduction), nodule number, nodule dry matter, and growth of four soybean genotypes (Williams 82, PI 416937, DR-1 [an Egyptian cultivar], and NOD1-3 [a hypernodulating mutant selected from Williams]) were investigated in hydroponic cultures and growth chamber environments. Salt stress significantly inhibited nitrogenase activity, nodule number, and dry matter accumulation per plant of all four cultivars. The detrimental effects of salinity on nodulation parameters and dry matter accumulation were most pronounced for NOD1-3 and Williams 82, intermediate for DR-l, and less marked for PI 416937. Self-grafted NOD1-3 plants showed 50 to 62% inhibition in nodulation responses (activity, number, mass) while grafting of P1416937 scions to NOD1-3 roots resulted in less than 7% inhibition by salt. Nodule number on PI 416937 roots was greater when grafted to NOD1-3 scions (relative to self-grafted PI 416937 plants), confirming a shoot role in autoregulation of nodule number. Conclusions are that shoot factors are of primary importance in determining salt-tolerance of the PI 416937 genotype and that hypernodulation expression in the mutant is negatively affected by salt treatment.

ABSTRACT. Inoculation of different plant wastes with microorganisms resulted in a release of maximum reducing sugars
(33 %) from sugar-cane leaves when subjected to Penicillium oxalicun,. Maximum protein was formed from sugar-cane bagasse
inoculated with Aspergillus fumigatus. Association of sugar-cane leaves with P. oxalicurn showed the highest digestibility. The
use of such microorganisms may help to provide additional and valuable proteins ultimately for human use.

Abstract This study was performed to evaluate the ability
of cellulolytic fungi and wheat straw incorporation to
improve the nodulation, growth and nitrogen status of fenugreek
grown in saline soils. NaCl addition to the growth
medium at rates of 0.5 and 1% strongly decreased the enzymatic
activity of the ten tested moulds. Three of these
fungi, Aspergillus niger, Chaetomium globosum and Trichoderma
harzianum, showed the highest enzymatic activity.
The three moulds have the ability to degrade straw in
the presence of NaCl and T. harzianum was the best straw
degrader. Inoculating the plants with Rhizobium meliloti
strain TAL 1373 and cellulolytic fungi slightly promoted
nodulation, growth and nitrogen accumulation when plants
were grown with the addition of 0.5% NaCl when compared
to plants inoculated with R. meliloti alone. However,
application of wheat straw with cellulolytic fungi significantly
enhanced growth, nodulation and nodule efficiency
at 0.5 and 1.0% salinity. The greatest values of nodulation
and growth parameters were obtained with a straw-Trichoderma
harzianum combination. Cellulolytic fungi and
wheat straw increased the concentration of Ca, Mg and K
in the shoots and roots of plants. The increase in dry matter
production and N content was mainly due to improved
N2 fixation reflected by enhanced formation and growth of
nodules as well as nitrogenase activity.

ABSTRACT. Survival and nitrogenase efficiency of Nostoc commune and N. austinii were evaluated monthly in four carrier
materials (sugarcane bagasse, wheat straw, wheat bran and peat) at 10, 30 and 40 ~ Survival, as well as nitrogenase activity, of
both species was much better in peat, followed by wheat bran, sugarcane bagasse than in wheat straw at 10 and 30 ~ up to
three months, the activity of N. commune being better than N. austinff. None of the materials tested was found to be superior
to peat as carrier of Nostoc species but the results indicated that wheat bran and sugarcane bagasse can be used as inoculant
carriers with relative success. Storage of inoculants in these carriers is feasible at 30 ~ up to three months

Abstract Tomato fruits and seed lots were screened for
the presence of Xanthomonas vesicatoria and Ralstonia
solanacearum. Yellow colonies of Xanthomonas vesicatoria
and white colonies of Ralstonia solanacearum were
consistently isolated on yeast extract-dextrose-calcium
carbonate agar medium (YDC) from diseased fruits and
seed samples. This was confirmed by isolation on semiselective
medium such as Tween B for Xanthomonas and
triphenyltetrazolium salt (TTC) medium for Ralstonia solanacearum
followed by biochemical tests. The four
isolates belonging to Xanthomonas vesicatoria and Ralstonia
solanacearum were used to inoculate a local tomato
variety. The isolates were found to cause yellowing and
wilting of 2-weeks-old seedlings by 8–14 days after inoculation
and by 4 weeks all plants hadwilted and completely died.
Bacteria with the same characteristics as those inoculated
were reisolated from the infected plants. Uninoculated plants
remained healthy.

Common bean seed lots collected from different seed dealers and Malawii agriculture station
were screened for the presence of Xanthomonas axonopodis pv. phaseoli. In the laboratory the pathogen was
isolated following the routine laboratory assay method, i.e. direct plating method using yeast extract–dextrose–
calcium carbonate agar medium (YDC). Yellow, convex, mucoid colonies of Xanthomonas were consistently
isolated on YDC from seed samples. The presumptive pathogen was confirmed by isolation on
semiselective medium, such as mTBM and MD5A. Further, the pathogen was confirmed by biochemical,
physiological and, finally, the pathogenicity tests. Five samples out of seven were positive for Xanthomonas.
The isolates were found to cause common blight of 3-week-old common bean plants by 7 d after inoculation.
Bacteria with the same characteristics as those inoculated were re-isolated from the infected plants.