Effect of Nostoc sp. (Cyanobacteria) on soil characteristics, plant growth and nutrient uptake
2006
Obana, S. | Miyamoto, K. | Morita, S. | Ohmori, M. | Inubushi, K.
The arid desert area is expanding 6 million ha a year. The terrestrial cyanobacteria Nostoc is known as a pioneer organism which can photosynthesize, fix atmospheric nitrogen, and secrete polysaccharides. In order to explore the potentiality of Nostoc to be utilized for countermeasures to soil diverfication, the authors investigated the effect of Nostoc on soil chemical and physical properties, as well as plant growth, in outdoor and laboratory experiments. They also examined relationship between colony shape and characteristic. Nostoc was applied on the soil surface inside plastic containers and cultivated outdoors for 90 days, and soil properties were measured. On soil-less culture, Nostoc was applied in plastic dishes, after which Komatsuna (Brassica campestris) was seeded and incubated inside growth chambers for 14 days to analyze plant growth and nutrient uptake. Two colonies of Nostoc with different shapes were examined for tolerance of dryness and salinity. Organic C and N contents in the soil surface increased, but temperature and soil moisture remained more constant in Nostoc-applied soil compared with to un-amended soil. Plant growth was enhanced when Nostoc was applied, compared to un-amended soil. In addition, plants' iron uptake was enhanced by Nostoc more than without Nostoc. On the other hand, Round-shape Nostoc had high tolerances of dryness and salinity than Irregularly-shaped algae. Round algae were suited to retification of problematic soil better than Irregular ones. The results indicated that the application of Nostoc to the soil presents a potential for organic matter production, and could be a tool to reclaim degraded soil ecosystems. Nostoc adequate for application was selected based on tolerance to dryness and salinity. Further studies are needed to develop greater understanding of relationship of Nostoc and plant growth. Long-term field experiments are also necessary.
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