نتایج جستجو برای: n fixation bacteria
تعداد نتایج: 1189011 فیلتر نتایج به سال:
Biological nitrogen (N) fixation is the primary source of “new” N to unmanaged ecosys tems, and recent analyses suggest that terrestrial N inputs via free-living N fixation may be more impor tant than previously assumed. This may be particularly true in some tropical rain forests, where free-living fixation could outpace symbiotic N fixation to repre sent the dominant source of new N inputs....
Symbiotic nitrogen (N) fixing trees are absent from old-growth temperate and boreal ecosystems, even though many of these are N-limited. To explore mechanisms that could select against N fixation in N-limited, old-growth ecosystems, we developed a simple resource-based evolutionary model of N fixation. When there are no costs of N fixation, increasing amounts of N fixation will be selected for ...
Abstract. 1. Wood decomposition is characterised by complex and poorly understood nitrogen (N) dynamics with unclear implications for forest nutrient cycling and productivity. Wood-dwelling microbes have developed unique strategies for coping with the N limitations imposed by their substrate, including the translocation of N into wood by cord-forming fungi and the fixation of atmospheric nitrog...
*An extensive survey of nodulation in the legume genus Mimosa was undertaken in two major biomes in Brazil, the Cerrado and the Caatinga, in both of which there are high degrees of endemicity of the genus. *Nodules were collected from 67 of the 70 Mimosa spp. found. Thirteen of the species were newly reported as nodulating. Nodules were examined by light and electron microscopy, and all except ...
The nitrogen-fixing symbiosis between rhizobia and legume plants is a model of coevolved nutritional complementation. The plants reduce atmospheric CO(2) by photosynthesis and provide carbon compounds to symbiotically associated bacteria; the rhizobia use these compounds to reduce (fix) atmospheric N(2) to ammonia, a form of nitrogen the plants can use. A key feature of symbiotic N(2) fixation ...
A hypothesis that ultraviolet-induced mutagenesis arises from the induction of an error-prone mode of postreplication repair that requires the exrA+ recA+ genotype has been tested with alkaline sucrose gradient centrifugation coupled with assays of fixation determined by loss of photoreversibility. The inhibitor of protein synthesis, chloramphenicol, added before irradiation, prevented a small ...
The Gram-negative soil bacteria of the family Rhizobiaceae can fonn nodules on the roots of leguminous plants and as a result are able to fix nitrogen. This partnership is highly specific as particular legumes are generally infected by one rhizobial species only (for example alfalfa by R. meliloti and soybean by B. japonicum'i. The establishment of the symbiosis is a multistepped, interactive p...
Vent and seep animals harness chemosynthetic energy to thrive far from the sun's energy. While symbiont-derived energy fuels many taxa, vent crustaceans have remained an enigma; these shrimps, crabs, and barnacles possess a phylogenetically distinct group of chemosynthetic bacterial epibionts, yet the role of these bacteria has remained unclear. We test whether a new species of Yeti crab, which...
Traditionally, cyanobacterial activity in oceanic photic layers was considered responsible for the marine pelagic dinitrogen (N2) fixation. Other potentially N2-fixing bacteria and archaea have also been detected in the pelagic water column, however, the activity and importance of these non-cyanobacterial diazotrophs (NCDs) remain poorly constrained. In this perspective we summarize the N2 fixa...
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