Rhizobium-Legume Symbiosis and Nitrogen Fixation under Severe Conditions and in an Arid Climate
AUTOR(ES)
Zahran, Hamdi Hussein
FONTE
American Society for Microbiology
RESUMO
Biological N2 fixation represents the major source of N input in agricultural soils including those in arid regions. The major N2-fixing systems are the symbiotic systems, which can play a significant role in improving the fertility and productivity of low-N soils. The Rhizobium-legume symbioses have received most attention and have been examined extensively. The behavior of some N2-fixing systems under severe environmental conditions such as salt stress, drought stress, acidity, alkalinity, nutrient deficiency, fertilizers, heavy metals, and pesticides is reviewed. These major stress factors suppress the growth and symbiotic characteristics of most rhizobia; however, several strains, distributed among various species of rhizobia, are tolerant to stress effects. Some strains of rhizobia form effective (N2-fixing) symbioses with their host legumes under salt, heat, and acid stresses, and can sometimes do so under the effect of heavy metals. Reclamation and improvement of the fertility of arid lands by application of organic (manure and sewage sludge) and inorganic (synthetic) fertilizers are expensive and can be a source of pollution. The Rhizobium-legume (herb or tree) symbiosis is suggested to be the ideal solution to the improvement of soil fertility and the rehabilitation of arid lands and is an important direction for future research.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=98982Documentos Relacionados
- Nodulation Factor for Rhizobium-Legume Symbiosis1
- Heme synthesis in the rhizobium-legume symbiosis: a palette for bacterial and eukaryotic pigments.
- Structure-Function Analysis of Nod Factor-Induced Root Hair Calcium Spiking in Rhizobium-Legume Symbiosis1
- Effects of Boron on Rhizobium-Legume Cell-Surface Interactions and Nodule Development.
- DNA Content of Free Living Rhizobia and Bacteroids of Various Rhizobium-Legume Associations