Biological nitrogen fixation: A key to world protein

Hardy, R. W. F.; Burns, R. C.; Hebert, Richard R.; Holsten, R. D.; Jackson, E. K.

doi:10.1007/bf02661879

Cited by 87 publications

(51 citation statements)

References 41 publications

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“…9). Greater than 90% of the N2 fixed occurred post-flowering, which was similar to previous reports (3,4). The seasonal amount of N2 fixed by the plants from the 1/4X treatment was less than 10% of the level reported by Hardy et al (4), which indicated that even the 1/4X nutrient treatment was considerably inhibitory to N2-fixation.…”

supporting

confidence: 90%

“…Nitrogen fixation is normally initiated in soybeans 20 to 30 days after planting (3). Thus, initial nitrogen requirements must be met through utilization of nitrogen from the seed and nitrogen from the soil.…”

mentioning

confidence: 99%

“…Thus, initial nitrogen requirements must be met through utilization of nitrogen from the seed and nitrogen from the soil. Recent estimates indicate that some 25 to 30% (80-110 kg N per hectare per season) of the total plant nitrogen was supplied through the N2-fixation process in soybeans as measured with the acetylene-reduction technique (3,4). It has also been estimated by Kjeldahl and 15N analysis that 95 kg N per hectare per season were supplied through fixation by soybeans (11 Growth Stages.…”

mentioning

confidence: 99%

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Canopy and Seasonal Profiles of Nitrate Reductase in Soybeans (Glycine max L. Merr.)

Harper

Hageman²

1972

Plant Physiol.

142

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Nitrate reductase activity of soybeans (Glycine max L. Merr.) was evaluated in soil plots and outdoor hydroponic gravel culture systems throughout the growing season. Nitrate reductase profiles within the plant canopy were also established. Mean activity per gram fresh weight per hour of the entire plant canopy was highest in the seedling stage while total activity (activity per gram fresh weight per hour times the total leaf weight) reached a maximum when plants were in the full bloom to midpod fill stage. Nitrate reductase activity per gram fresh weight per hour was highest in the uppermost leaf just prior to full expansion and declined with leaf positions lower in the canopy. Total nitrate reductase activity per leaf was also highest in the uppermost fully expanded leaf during early growth stages. Maximum total activity shifted to leaf positions lower in the plant canopy with later growth stages.Nitrate reductase activity of soybeans grown in hydroponic systems was significantly higher than activity of adjacent soil grown plants at later growth stages, which suggested that under normal field conditions the potential for nitrate utilization may not be realized. Nitrate reductase activity per gram fresh weight per hour and nitrate content were positively correlated over the growing season with plants grown in either soil or solution culture. Computations based upon the nitrate reductase assay of plants grown in hydroponics indicated that from 1.7 to 1.8 grams N could have been supplied to the plant via the nitrate reductase process. The harvested seed contained 1.1 to 1.2 grams N per plant. Thus, based on previous estimates of approximately 32% of the final N distribution being in the vegetative plant parts, the estimated input of reduced nitrogen via the enzyme assay was in agreement with the actual N accumulation.The amount of calculated N2-fixation by nodules per season with plants grown in hydroponics was less than 2 % of the computed nitrate reduced via leaf nitrate reductase. Thus, the level of nitrate in the nutrient solution appeared to be quite inhibitory to N2-fixation.The response of the soybean plant to nitrogen is confounded by the ability of the plant to utilize both nitrate and N2. Nitrate is considered the primary source of nitrogen available from the soil. The uptake of nitrate and subsequent reduction by nitrate reductase is the primary pathway of soil nitrogen utilization. The utilization of N2 through the symbiotic relationship with Rhizobium japonicum (Kirchner) Buchanan affords a second major pathway of nitrogen input to soybeans.Nitrogen fixation is normally initiated in soybeans 20 to 30 days after planting (3). Thus, initial nitrogen requirements must be met through utilization of nitrogen from the seed and nitrogen from the soil. Recent estimates indicate that some 25 to 30% (80-110 kg N per hectare per season) of the total plant nitrogen was supplied through the N2-fixation process in soybeans as measured with the acetylene-reduction technique (3, 4). It has also been estim...

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supporting

confidence: 90%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Canopy and Seasonal Profiles of Nitrate Reductase in Soybeans (Glycine max L. Merr.)

Harper

Hageman²

1972

Plant Physiol.

142

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“…On the other hand, there are reports with Glycine max and Arachis spec. [17] of an increase in nitrogen fixation in field experiments at the time of seed formation. Of the many factors, different in phytotron and field experiments, the light dark regime alone influences in addition to nitrogenase activity transpiration and the amino acid and sugar contents as well [18].…”

Section: Discussionmentioning

confidence: 94%

Differentiation of Rhizobium japonicum. II. Enzymatic Activities in Bacteroids and Plant Cytoplasm during the Development of Nodules of Glycine max

Stripf

Werner

1978

Zeitschrift Für Naturforschung C

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Phytotron grown plants of Glycine max var. Caloria infected with Rhizobium japonicum 61-A-101 under controlled conditions as 14 d old seedlings develop a sharp maximum of nitrogenase activity of 13 ± 3 nmol C2H4 · h-1 · mg nodule fresh weight-1 19 d after infection, followed by a long period of reduced activity (3 -5 nmol) between 30 and 45 days after infection. A higher maximum activity (18 nmol C2H4 · h-1 · mg nodule-1, lasting 7 days was found in Glycine max var. Mandarin, with a similar peroid of low activity (3 - 4 nmol) following, between 35 and 50 d after infection. Nitrogenase activity in the varieties infected with Rhizobium japonicum strain 3I1 b 85 is very similar. In both varieties, the leghaemoglobin continues to increase (3 fold) after the maximum nitrogenase activity is reached and starts to decline only after 35 to 40 d. Specific activities of the three enzymes aspartate aminotransferase (E.C.2.6.1.1.), glutamate dehydrogenase (E.C.1.4.1.2.) and alanine aminotransferase (E.C.2.6.1.2.) in the plant cell cytoplasm are changing very similarly to nitrogenase activity in the bacteroids, whereas the specific activities of the three enzymes in the bacteroids decrease only very slightly between 19 and 45 d. For these 3 enzymes the specific activity in the bacteroids during the phase of maximum nitrogenase activity is only 20 - 40% of the specific activity in the cytoplasm. A constant low activity (0.350 units) of glutamine synthetase (E.C.6.3.1.2.) is found in bacteroids from 19 to 45 d old nodules, whereas the specific activity in the plant cytoplasm increases from about 1.2 units at 19 d to more than 6 units at 45 d. The specific activity of GOGAT (E.C.1.4.13.) in bacteroids is 2 - 3 times higher than in the plant cell cytoplasm and increases slightly. Alanine dehydrogenase (E.C.1.4.1.1.) and 3-hydroxybutyrate dehydrogenase (E.C.1.1.1.30.) activities in bacteroids increase between 19 and 35 d after infection by a factor of 2 - 3. In 35 - 45 d old nodules, the specific activity of aianine-dh in bacteroids of the same Rhizobium japonicum strain (61-A-101) from plant var. Caloria is significantly smaller than in bacteroids from plant var. Mandarin, whereas for 3-hydroxybutyrate-dh the activity in bacteroids from var. Caloria is enhanced compared to bacteroids from var. Mandarin.

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“…In annual legume systems, the rhizobia symbiosis must be reestablished every growing season; therefore, the symbiosis only exists for a portion of the plant's lifecycle. As a result, the symbiosis may not wholly supply the annual grain legume's inorganic N requirement and often does little to improve soil N or nutrient status because nearly all BNF N and plant resources are mobilized and translocated to the seed [19]. Conversely for perennial grain legumes, the symbiosis exists and functions during the entirety of each growing season.…”

Section: Introductionmentioning

confidence: 99%

Perennial Grain Legume Domestication Phase I: Criteria for Candidate Species Selection

et al. 2018

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Annual cereal and legume grain production is dependent on inorganic nitrogen (N) and other fertilizers inputs to resupply nutrients lost as harvested grain, via soil erosion/runoff, and by other natural or anthropogenic causes. Temperate-adapted perennial grain legumes, though currently non-existent, might be uniquely situated as crop plants able to provide relief from reliance on synthetic nitrogen while supplying stable yields of highly nutritious seeds in low-input agricultural ecosystems. As such, perennial grain legume breeding and domestication programs are being initiated at The Land Institute (Salina, KS, USA) and elsewhere. This review aims to facilitate the development of those programs by providing criteria for evaluating potential species and in choosing candidates most likely to be domesticated and adopted as herbaceous, perennial, temperate-adapted grain legumes. We outline specific morphological and ecophysiological traits that may influence each candidate's agronomic potential, the quality of its seeds and the ecosystem services it can provide. Finally, we suggest that perennial grain legume breeders and domesticators should consider how a candidate's reproductive biology, genome structure and availability of genetic resources will determine its ease of breeding and its domestication timeline.

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Biological nitrogen fixation: A key to world protein

Cited by 87 publications

References 41 publications

Canopy and Seasonal Profiles of Nitrate Reductase in Soybeans (Glycine max L. Merr.)

Canopy and Seasonal Profiles of Nitrate Reductase in Soybeans (Glycine max L. Merr.)

Differentiation of Rhizobium japonicum. II. Enzymatic Activities in Bacteroids and Plant Cytoplasm during the Development of Nodules of Glycine max

Perennial Grain Legume Domestication Phase I: Criteria for Candidate Species Selection

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