Role of N2-fixation in the sustainability of the ponded grass pasture system

Weier, K. L.; Pittaway, Pam; Wildin, J. H.

doi:10.1016/0038-0717(95)98616-v

Cited by 6 publications

(2 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Bacteria capable of performing N 2 -fixation can colonize both root surfaces (and are referred to as “epiphytes” here) as well as the internal tissues (“endophytes”) (for review see [ 7 ]. The reduction of N 2 to ammonia during its biological fixation is an energetically expensive process and the input of easily available C from roots into the plant rhizosphere can sustain high activity of root associated diazotrophs [ 8 , 9 , 10 , 11 ]. Epiphytic diazotrophs establishing loosely organized associative relationships in the rhizosphere have been documented frequently for tropical grasses [ 8 , 12 , 13 ] and among wetland plants for littoral macrophytes [ 14 , 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

“…The reduction of N 2 to ammonia during its biological fixation is an energetically expensive process and the input of easily available C from roots into the plant rhizosphere can sustain high activity of root associated diazotrophs [ 8 , 9 , 10 , 11 ]. Epiphytic diazotrophs establishing loosely organized associative relationships in the rhizosphere have been documented frequently for tropical grasses [ 8 , 12 , 13 ] and among wetland plants for littoral macrophytes [ 14 , 15 , 16 ]. Endophytic relationships of diazotrophs have been reported in a variety of plant roots and rhizomes including sugar cane, Sorghum , Miscanthus , and others [ 17 , 18 , 19 , 20 , 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Heterotrophic N2-fixation contributes to nitrogen economy of a common wetland sedge, Schoenoplectus californicus

et al. 2018

View full text Add to dashboard Cite

A survey of the ecological variability within 52 populations of Schoenoplectus californicus (C.A. Mey.) Soják across its distributional range revealed that it is commonly found in nitrogen (N) limited areas, but rarely in phosphorus limited soils. We explored the hypothesis that S. californicus supplements its nitrogen demand by bacterial N2-fixation processes associated with its roots and rhizomes. We estimated N2-fixation of diazotrophs associated with plant rhizomes and roots from several locations throughout the species’ range and conducted an experiment growing plants in zero, low, and high N additions. Nitrogenase activity in rhizomes and roots was measured using the acetylene reduction assay. The presence of diazotrophs was verified by the detection of the nifH gene. Nitrogenase activity was restricted to rhizomes and roots and it was two orders of magnitude higher in the latter plant organs (81 and 2032 nmol C2H4 g DW-1 d-1, respectively). Correspondingly, 40x more nifH gene copies were found on roots compared to rhizomes. The proportion of the nifH gene copies in total bacterial DNA was positively correlated with the nitrogenase activity. In the experiment, the contribution of fixed N to the plant N content ranged from 13.8% to 32.5% among clones from different locations. These are relatively high values for a non-cultivated plant and justify future research on the link between N-fixing bacteria and S. californicus production.

show abstract