0 the process by which nitrogen from the atmosphere is changed either naturally or in industry into compounds that are used in several processes -- 固氮
Therefore, nitrogen fixation is unimportant as a source of this element for savanna plants.
These hypotheses will be tested as additional genomic, biochemical and geological evidence sheds more light on the evolution of nitrogen fixation, photosynthesis and cyanobacteria.
The objective of the present experiment was to assess seed composition and nitrogen fixation under these conditions.
Thus, at this point, the phylogenetic and molecular evidence indicate that nitrogen fixation arose before photosynthesis, but more work on this question is needed.
The evolution of nitrogen fixation also appears to have been a precondition for the evolution of (bacterio)chlorophyll-based photosynthesis.
This model involves the interplay of denitrification, nitrification and nitrogen fixation, but does not explicitly consider the influence of tracemetal availability for requisite enzyme activity.
By providing soil cover and nitrogen fixation they not only improve livestock feed but also help prevent soil degradation.
These results indicate that brassica residues could affect critical microbial processes, including nitrification, nitrogen fixation and mycorrhizal symbioses.
