scholarly journals Current Nitrogen Fixation Is Involved in the Regulation of Nitrogenase Activity in White Clover (Trifolium repens L.)

1993 ◽  
Vol 103 (3) ◽  
pp. 1009-1014 ◽  
Author(s):  
I. Heim ◽  
U. A. Hartwig ◽  
J. Nosberger
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Trifolium Repens ◽  
Nitrogenase Activity ◽  
Trifolium Repens L

Nitrogen Fixation in Hybrids of White Clover (Trifolium repens L.) and Caucasian Clover (Trifolium ambiguum M. Bieb)

2000 ◽  
Vol 185 (4) ◽  
pp. 241-247 ◽  
Author(s):  
M. T. Abberton ◽  
J. H. MacDuff ◽  
S. Vagg ◽  
A. H. Marshall ◽  
T. P. T. Michaelson-Yeates
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Trifolium Repens ◽  
Trifolium Ambiguum ◽  
Trifolium Repens L

scholarly journals A reduced fraction of plant N derived from atmospheric N (%Ndfa) and reduced rhizobial nifH gene numbers indicate a lower capacity for nitrogen fixation in nodules of white clover exposed to long-term CO<sub>2</sub> enrichment

2013 ◽  
Vol 10 (12) ◽  
pp. 8269-8281 ◽  
Author(s):  
T. Watanabe ◽  
S. Bowatte ◽  
P. C. D. Newton
Keyword(s):  
Nitrogen Fixation ◽  
Elevated Co2 ◽  
White Clover ◽  
Trifolium Repens ◽  
Nifh Gene ◽  
Shoot Biomass ◽  
N Fixation ◽  
Dna Amount ◽  
Trifolium Repens L ◽  
Nifh Genes

Abstract. Using the δ15N natural abundance method, we found that the fraction of nitrogen derived from atmospheric N (%Ndfa) in field-grown white clover (Trifolium repens L.) plants was significantly lower (72.0% vs. 89.8%, p = 0.047 in a grassland exposed to elevated CO2 for 13 yr using free air carbon dioxide enrichment (FACE). Twelve months later we conducted an experiment to investigate the reasons behind the reduced N fixation. We took cuttings from white clover plants growing in the FACE and established individual plants in a glasshouse using soil from the appropriate ambient or elevated CO2 treatments. The established plants were then transplanted back into their "rings of origin" and sampled over a 6-week period. We used molecular ecological analyses targeting nifH genes and transcripts of rhizobia in symbiosis with white clover (Trifolium repens L.) to understand the potential mechanisms. Shoot biomass was significantly lower in eCO2, but there was no difference in nodule number or mass per plant. The numbers of nifH genes and gene transcripts per nodule were significantly reduced under eCO2, but the ratio of gene to transcript number and the strains of rhizobia present were the same in both treatments. We conclude that the capacity for biological nitrogen fixation was reduced by eCO2 in white clover and was related to the reduced rhizobia numbers in nodules. We discuss the finding of reduced gene number in relation to factors controlling bacteroid DNA amount, which may imply an influence of nitrogen as well as phosphorus.

scholarly journals A reduced fraction of plant N derived from atmospheric N (%Ndfa) and reduced rhizobial nifH gene numbers indicate a lower capacity for nitrogen fixation in nodules of white clover exposed to long-term CO<sub>2</sub> enrichment

2013 ◽  
Vol 10 (6) ◽  
pp. 9867-9896 ◽  
Author(s):  
T. Watanabe ◽  
S. Bowatte ◽  
P. C. D. Newton
Keyword(s):  
Nitrogen Fixation ◽  
Elevated Co2 ◽  
White Clover ◽  
Trifolium Repens ◽  
Nifh Gene ◽  
Shoot Biomass ◽  
N Fixation ◽  
Dna Amount ◽  
Trifolium Repens L ◽  
Nifh Genes

Abstract. Using the δ15N natural abundance method, we found that the fraction of nitrogen derived from atmospheric N (%Ndfa) in field grown white clover (Trifolium repens L.) plants was significantly lower (72.0% vs. 89.5%, p = 0.047 in a grassland exposed to elevated CO2 for 13 yr using Free Air Carbon Dioxide Enrichment (FACE). Twelve months later we conducted an experiment to investigate the reasons behind the reduced N fixation. We took cuttings from white clover plants growing in the FACE and established individual plants in a glasshouse using soil from the appropriate ambient or elevated CO2 treatments. The established plants were then transplanted back into their "rings of origin" and sampled over a 6 week period. We used molecular ecological analyses targeting nifH genes and transcripts of rhizobia in symbiosis with white clover (Trifolium repens L.) to understand the potential mechanisms. Shoot biomass was significantly lower in eCO2 but there was no difference in nodule number or mass per plant. The numbers of nifH genes and gene transcripts per nodule were significantly reduced under eCO2 but the ratio of gene to transcript number and the strains of rhizobia present were the same in both treatments. We conclude that the capacity for biological nitrogen fixation was reduced by eCO2 in white clover and was related to the reduced rhizobia numbers in nodules. We discuss the finding of reduced gene number in relation to factors controlling bacteroid DNA amount which may imply an influence of nitrogen as well as phosphorus.

Nitrogen Fixation by Hybrids of White Clover (Trifolium repens L.) and Trifolium nigrescens

1999 ◽  
Vol 183 (1) ◽  
pp. 27-33 ◽  
Author(s):  
M. T. Abberton ◽  
J. H. MacDuff ◽  
A. H. Marshall ◽  
T. P. T. Michaelson-Yeates
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Trifolium Repens ◽  
Trifolium Repens L ◽  
Trifolium Nigrescens
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