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

Survival and nitrogenase efficiency ofNostoc commune andN. austinii were evaluated monthly in four carrier materials (sugarcane bagasse, wheat straw, wheat bran and peat) at 10, 30 and 40 °C. 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 °C up to three months, the activity ofN. commune being better thanN. austinii. None of the materials tested was found to be superior to peat as carrier ofNostoc 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 °C up to three months.

The ability of different microorganisms to alleviate the noxious effect of salinity was tested. Barley grains were planted under salt stress and were inoculated with cyanobacteria, Pseudomonas fluorescens and Dunaliella tertiolecta. All tested microorganisms improved growth of barley plants as indicated by dry weight, photosynthetic pigments and vitality of the plants. Cyanobacterial inoculant was the most effective and significantly diminished the adverse effect of salinity. Results of the present study hold promise for use of such microorganisms to cultivate plants in saline soils.

Faba bean cv. Giza 3 was grown in hydroponic cultures and inoculated with Rhizobium leguminosarum bv. viceae TAL 1402. Salinity levels at 40, 80 and 120 mM NaCl were applied at transplanting and inoculation. The highest level of salinity level (120 mM) significantly suppressed nodulation, nitrogenase activity and plant growth. This salinity level also significantly decreased the concentrations of macro and micro nutrients in faba bean leaves. X-ray microanalyses of nodules under high levels of NaCl indicate that Ca, K, Mg and S were lower in the infected and uninfected cells of faba bean nodules than control ones, whereas, Na and Cl were higher. Nitrogen content of nodules was significantly higher in plants treated with high salinity levels than nonsalinized ones. However, the N content of shoots was lower than the controls. The inhibition of nitrogenase activity at high levels of salt stress could be explained in terms of product inhibition of the enzyme as an efficient feedback regulation mechanism. The X-ray microanalysis results revealed that the N export from nitrogen-fixing cells is sensitive to salinity and is controlled by element distribution in nodules.