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Registro Completo |
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Biblioteca(s): |
Embrapa Agrobiologia; Embrapa Soja. |
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Data corrente: |
11/11/1992 |
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Data da última atualização: |
11/11/1992 |
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Autoria: |
VANCE, C. P.; HEICHEL, G. H. |
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Afiliação: |
USDA-ARS Plant Science Research, and the Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108-1013. |
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Título: |
Carbon in N2 fixation: limitation or exquisite adaptation. |
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Ano de publicação: |
1991 |
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Fonte/Imprenta: |
Annual Review of Plant Physiology and Plant Molecular Biology, v.42, p.373-392, 1991. |
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Idioma: |
Inglês
Português |
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Conteúdo: |
Nodule carbon metabolism and the energy photosynthate requirements for symbiotic N2 fixation have been fertile research topics for many years because of the continuing debate over whether N2 or N03- reduction is more beneficial to crop productivity (38, 50, 58, 85, 98, 99). Interest in the topic continues, driven by several questions of scientific and technological importance. Do the carbon requirements for symbiotic N2 fixation limit productivity of legumes? How does the host plant nodule, functioning for all practical purposes in an O2-limited environment, provide sufficient carbon to the microsymbiont to fuel nitrogenase (N2ase)? Will transforming non-N2-fixing species to fix N2 impair their productivity? Recent observations that leghemoglobin (Lb) may be present in all plant species (4, 9), that rhizobia can elicit nodule-like structures on rice and other monocots (1,13), and that single gene changes in the legume host can result in supernodulating plants (12, 47) provide incentives for understanding the role of carbon pathways in N2 fixation beyond those traditionally advanced for legumes. The objectives of this review are to examine whether N2ase activity is carbon limited, to describle plausible mechanisms whereby plant metabolism adapted to an O2-limited environment to provide carbon for N2 fixarion, and to delineate how O2 diffusion into the nodule may be regulated. It is beyond the scope of this article to detail each aspect of all events impinging upon nodule carbon and nitrogen metabolism. For a more co MenosNodule carbon metabolism and the energy photosynthate requirements for symbiotic N2 fixation have been fertile research topics for many years because of the continuing debate over whether N2 or N03- reduction is more beneficial to crop productivity (38, 50, 58, 85, 98, 99). Interest in the topic continues, driven by several questions of scientific and technological importance. Do the carbon requirements for symbiotic N2 fixation limit productivity of legumes? How does the host plant nodule, functioning for all practical purposes in an O2-limited environment, provide sufficient carbon to the microsymbiont to fuel nitrogenase (N2ase)? Will transforming non-N2-fixing species to fix N2 impair their productivity? Recent observations that leghemoglobin (Lb) may be present in all plant species (4, 9), that rhizobia can elicit nodule-like structures on rice and other monocots (1,13), and that single gene changes in the legume host can result in supernodulating plants (12, 47) provide incentives for understanding the role of carbon pathways in N2 fixation beyond those traditionally advanced for legumes. The objectives of this review are to examine whether N2ase activity is carbon limited, to describle plausible mechanisms whereby plant metabolism adapted to an O2-limited environment to provide carbon for N2 fixarion, and to delineate how O2 diffusion into the nodule may be regulated. It is beyond the scope of this article to detail each aspect of all events impinging upon nodule carb... Mostrar Tudo |
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Marc: |
LEADER 01937naa a2200133 a 4500
001 1458309
005 1992-11-11
008 1991 bl --- 0-- u #d
100 1 $aVANCE, C. P.
245 $aCarbon in N2 fixation$blimitation or exquisite adaptation.
260 $c1991
520 $aNodule carbon metabolism and the energy photosynthate requirements for symbiotic N2 fixation have been fertile research topics for many years because of the continuing debate over whether N2 or N03- reduction is more beneficial to crop productivity (38, 50, 58, 85, 98, 99). Interest in the topic continues, driven by several questions of scientific and technological importance. Do the carbon requirements for symbiotic N2 fixation limit productivity of legumes? How does the host plant nodule, functioning for all practical purposes in an O2-limited environment, provide sufficient carbon to the microsymbiont to fuel nitrogenase (N2ase)? Will transforming non-N2-fixing species to fix N2 impair their productivity? Recent observations that leghemoglobin (Lb) may be present in all plant species (4, 9), that rhizobia can elicit nodule-like structures on rice and other monocots (1,13), and that single gene changes in the legume host can result in supernodulating plants (12, 47) provide incentives for understanding the role of carbon pathways in N2 fixation beyond those traditionally advanced for legumes. The objectives of this review are to examine whether N2ase activity is carbon limited, to describle plausible mechanisms whereby plant metabolism adapted to an O2-limited environment to provide carbon for N2 fixarion, and to delineate how O2 diffusion into the nodule may be regulated. It is beyond the scope of this article to detail each aspect of all events impinging upon nodule carbon and nitrogen metabolism. For a more co
700 1 $aHEICHEL, G. H.
773 $tAnnual Review of Plant Physiology and Plant Molecular Biology$gv.42, p.373-392, 1991.
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Registro original: |
Embrapa Soja (CNPSO) |
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