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Martin ML, Pervent M, Lambert I, Colella S, Tancelin M, Severac D, Clément G, Tillard P, Frugier F, Lepetit M. Localized osmotic stress activates systemic responses to N limitation in Medicago truncatula-Sinorhizobium symbiotic plants. FRONTIERS IN PLANT SCIENCE 2023; 14:1288070. [PMID: 38053772 PMCID: PMC10694431 DOI: 10.3389/fpls.2023.1288070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 10/24/2023] [Indexed: 12/07/2023]
Abstract
In mature symbiotic root nodules, differentiated rhizobia fix atmospheric dinitrogen and provide ammonium to fulfill the plant nitrogen (N) demand. The plant enables this process by providing photosynthates to the nodules. The symbiosis is adjusted to the whole plant N demand thanks to systemic N signaling controlling nodule development. Symbiotic plants under N deficit stimulate nodule expansion and activate nodule senescence under N satiety. Besides, nodules are highly sensitive to drought. Here, we used split-root systems to characterize the systemic responses of symbiotic plants to a localized osmotic stress. We showed that polyéthylène glycol (PEG) application rapidly inhibited the symbiotic dinitrogen fixation activity of nodules locally exposed to the treatment, resulting to the N limitation of the plant supplied exclusively by symbiotic dinitrogen fixation. The localized PEG treatment triggered systemic signaling stimulating nodule development in the distant untreated roots. This response was associated with an enhancement of the sucrose allocation. Our analyses showed that transcriptomic reprogramming associated with PEG and N deficit systemic signaling(s) shared many targets transcripts. Altogether, our study suggests that systemic N signaling is a component of the adaptation of the symbiotic plant to the local variations of its edaphic environment.
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Affiliation(s)
- Marie-Laure Martin
- Université Paris-Saclay, CNRS, INRAE, Univ d’Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
- Université Paris Cité, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
- Université Paris-Saclay, AgroParisTech, INRAE, UMR MIA, Paris-Saclay, Palaiseau, France
| | - Marjorie Pervent
- LSTM, Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Institut Agro Montpellier, Université de Montpellier, Montpellier, France
- PHIM Plant Health Institute, INRAE, Université de Montpellier, CIRAD, Institut Agro, IRD, Montpellier, France
| | - Ilana Lambert
- LSTM, Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Institut Agro Montpellier, Université de Montpellier, Montpellier, France
| | - Stefano Colella
- LSTM, Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Institut Agro Montpellier, Université de Montpellier, Montpellier, France
- PHIM Plant Health Institute, INRAE, Université de Montpellier, CIRAD, Institut Agro, IRD, Montpellier, France
| | - Mathilde Tancelin
- LSTM, Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Institut Agro Montpellier, Université de Montpellier, Montpellier, France
| | - Dany Severac
- MGX, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Gilles Clément
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Pascal Tillard
- Biologie et Physiologie Moléculaire des Plantes, INRAE, CNRS, Institut Agro Montpellier, Université de Montpellier, Montpellier, France
| | - Florian Frugier
- Université Paris-Saclay, CNRS, INRAE, Univ d’Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
- Université Paris Cité, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
| | - Marc Lepetit
- LSTM, Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Institut Agro Montpellier, Université de Montpellier, Montpellier, France
- Institut Sophia Agrobiotech, INRAE, CNRS, Université Côte d'Azur, Sophia-Antipolis, France
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Zhou S, Duursma RA, Medlyn BE, Kelly JW, Prentice IC. How should we model plant responses to drought? An analysis of stomatal and non-stomatal responses to water stress. AGRICULTURAL AND FOREST METEOROLOGY 2013; 182-183:204-214. [PMID: 0 DOI: 10.1016/j.agrformet.2013.05.009] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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Barigah TS, Bonhomme M, Lopez D, Traore A, Douris M, Venisse JS, Cochard H, Badel E. Modulation of bud survival in Populus nigra sprouts in response to water stress-induced embolism. TREE PHYSIOLOGY 2013; 33:261-74. [PMID: 23467748 DOI: 10.1093/treephys/tpt002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Understanding drought tolerance mechanisms requires knowledge about the induced weakness that leads to tree death. Bud survival is vital to sustain tree growth across seasons. We hypothesized that the hydraulic connection of the bud to stem xylem structures was critical for its survival. During an artificial drastic water stress, we carried out a census of bud metabolic activity of young Populus nigra L. trees by microcalorimetry. We monitored transcript expression of aquaporins (AQPs; plasma membrane intrinsic proteins (PIPs), X intrinsic proteins (XIPs) and tonoplast membrane intrinsic proteins (TIPs)) and measured local water status within the bud and tissues in the bearer shoot node by nuclear magnetic resonance (NMR) imaging. We found that the bud respiration rate was closely correlated with its water content and decreased concomitantly in buds and their surrounding bearer tissues. At the molecular level, we observed a modulation of AQP pattern expressions (PIP, TIP and XIP subfamilies) linked to water movements in living cells. However, AQP functions remain to be investigated. Both the bud and tree died beyond a threshold water content and respiration rate. Nuclear magnetic resonance images provided relevant local information about the various water reservoirs of the stem, their dynamics and their interconnections. Comparison of pith, xylem and cambium tissues revealed that the hydraulic connection between the bud and saturated parenchyma cells around the pith allowed bud desiccation to be delayed. At the tree death date, NMR images showed that the cambium tissues remained largely hydrated. Overall, the respiration rate (Rco2) and a few AQP isoforms were found to be two suitable, complementary criteria to assess the bud metabolic activity and the ability to survive a severe drought spell. Bud moisture content could be a key factor in determining the capacity of poplar to recover from water stress.
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Talibart R, Jebbar M, Gouesbet G, Himdi-Kabbab S, Wróblewski H, Blanco C, Bernard T. Osmoadaptation in rhizobia: ectoine-induced salt tolerance. J Bacteriol 1994; 176:5210-7. [PMID: 8071195 PMCID: PMC196703 DOI: 10.1128/jb.176.17.5210-5217.1994] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
After having shown that ectoine (a tetrahydropyrimidine) displays osmoprotective properties towards Escherichia coli (M. Jebbar, R. Talibart, K. Gloux, T. Bernard, and Blanco, J. Bacteriol. 174:5027-5035, 1992), we have investigated the involvement of this molecule in the osmotic adaptation of Rhizobium meliloti. Ectoine appeared almost as effective as glycine betaine in improving the growth of R. meliloti under adverse osmotic conditions (0.5 M NaCl). Moreover, improvement of growth of rhizobial strains insensitive to glycine betaine was also observed. Ectoine transport proved inducible, periplasmic protein dependent, and, as shown by competition experiments, distinct from the transport of glycine betaine. Medium osmolarity had little effect on the uptake characteristics, since the rate of influx increased from 12 to only 20 nmol min-1 mg of protein-1 when NaCl concentrations were raised from 0 to 0.3 or 0.5 M, with a constant of transport of 80 microM. Natural-abundance 13C-nuclear magnetic resonance and radiolabelling assays showed that ectoine, unlike glycine betaine, is not intracellularly accumulated and, as a consequence, does not repress the synthesis of endogenous compatible solutes (glutamate, N-acetylglutaminylglutamine amide, and trehalose). Furthermore, the strong rise in glutamate content in cells osmotically stressed in the presence of ectoine suggests that, instead of being involved in osmotic balance restoration, ectoine should play a key role in triggering the synthesis of endogenous osmolytes. Hence, we believe that there are at least two distinct classes of osmoprotectants: those such as glycine betaine or glutamate, which act as genuine osmolytes, and those such as ectoine, which act as chemical mediators.
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Affiliation(s)
- R Talibart
- Département Membranes et Osmorégulation, Centre National de la Recherche Scientifique (CNRS) URA 256, Rennes, France
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Fellows RJ, Patterson RP, Raper CD, Harris D. Nodule activity and allocation of photosynthate of soybean during recovery from water stress. PLANT PHYSIOLOGY 1987; 84:456-60. [PMID: 11539766 PMCID: PMC1056602 DOI: 10.1104/pp.84.2.456] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Nodulated soybean plants (Glycine max [L.] Merr. cv Ransom) in a growth-chamber study were subjected to a leaf water potential (psi w) of -2.0 megapascal during vegetative growth. Changes in nonstructural carbohydrate contents of leaves, stems, roots, and nodules, allocation of dry matter among plant parts, in situ specific nodule activity, and in situ canopy apparent photosynthetic rate were measured in stressed and nonstressed plants during a 7-day period following rewatering. Leaf and nodule psi w also were determined. At the time of maximum stress, concentration of nonstructural carbohydrates had declined in leaves of stressed, relative to nonstressed, plants, and the concentration of nonstructural carbohydrates had increased in stems, roots, and nodules. Sucrose concentrations in roots and nodules of stressed plants were 1.5 and 3 times greater, respectively, than those of nonstressed plants. Within 12 hours after rewatering, leaf and nodule psi w of stressed plants had returned to values of nonstressed plants. Canopy apparent photosynthesis and specific nodule activity of stressed plants recovered to levels for nonstressed plants within 2 days after rewatering. The elevated sucrose concentrations in roots and nodules of stressed plants also declined rapidly upon rehydration. The increase in sucrose concentration in nodules, as well as the increase of carbohydrates in roots and stems, during water stress and the rapid disappearance upon rewatering indicates that inhibition of carbohydrate utilization within the nodule may be associated with loss of nodule activity. Availability of carbohydrates within the nodules and from photosynthetic activity following rehydration of nodules may mediate the rate of recovery of N2-fixation activity.
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Affiliation(s)
- R J Fellows
- Battelle-Northwest, Richland, Washington 99352, USA
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Weisz PR, Denison RF, Sinclair TR. Response to drought stress of nitrogen fixation (acetylene reduction) rates by field-grown soybeans. PLANT PHYSIOLOGY 1985; 78:525-30. [PMID: 16664277 PMCID: PMC1064770 DOI: 10.1104/pp.78.3.525] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The effects of drought stress on soybean nodule conductance and the maximum rate of acetylene reduction were studied with in situ experiments performed during two seasons and under differing field conditions. In both years drought resulted in decreased nodule conductances which could be detected as early as three days after water was withheld. The maximum rate of acetylene reduction was also decreased by drought and was highly correlated with nodule conductance (r = 0.95). Since nodule conductance is equal to the nodule surface area times the permeability, the relationship of these variables to both whole-plant and unit-nodule nitrogenase activity was explored. Drought stress resulted in a decrease in nodule gas permeability followed by decreases in nodule surface area when drought was prolonged. Under all conditions studied acetylene reduction on a unit-nodule surface area basis was highly correlated with nodule gas permeability (r = 0.92). A short-term oxygen enrichment study demonstrated nodule gas permeability may limit oxygen flux into both drought-stressed and well-watered nodules of these field-grown soybeans.
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Affiliation(s)
- P R Weisz
- Agronomy Department, University of Florida, Gainesville, Florida 32611
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Khanna-Chopra R, Koundal KR, Sinha SK. A Simple Technique of Studying Water Deficit Effects on Nitrogen Fixation in Nodules without Influencing the Whole Plant. PLANT PHYSIOLOGY 1984; 76:254-6. [PMID: 16663809 PMCID: PMC1064266 DOI: 10.1104/pp.76.1.254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Cowpea (Vigna unguiculata L. Walp cv C-152) plants were grown in a system in which watering was withheld from the soil zone containing nodules, while the plants were able to maintain normal water status. The system was developed in a pot by making two soil zones, an upper and a lower separated by a gravel column between these two zones. Plants extended their roots into the lower layer of soil and were able to absorb water. The dry matter accumulation, photosynthesis rate, and leaf area development of the plant were not affected when the upper soil zone was dried, but the water potential of the nodules was lower than in the nodules in fully irrigated pots. Nitrogenase activity in the nodules obtained from plants stressed in the upper zone only was lower than in nodules obtained from fully irrigated plants. The present technique is helpful in distinguishing the direct water stress effects on nitrogen fixation compared to those mediated via photosynthate availability.
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Affiliation(s)
- R Khanna-Chopra
- Water Technology Center, Indian Agricultural Research Institute, New Delhi-110012, India
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9
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Dixon ROD, Wheeler CT. Biochemical, physiological and environmental aspects of symbiotic nitrogen fixation. ACTA ACUST UNITED AC 1983. [DOI: 10.1007/978-94-009-6878-3_5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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Abstract
An analysis of major U.S. crops shows that there is a large genetic potential for yield that is unrealized because of the need for better adaptation of the plants to the environments in which they are grown. Evidence from native populations suggests that high productivity can occur in these environments and that opportunities for improving production in unfavorable environments are substantial. Genotypic selection for adaptation to such environments has already played an important role in agriculture, but the fundamental mechanisms are poorly understood. Recent scientific advances make exploration of these mechanisms more feasible and could result in large gains in productivity.
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11
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Dejong TM, Phillips DA. Water Stress Effects on Nitrogen Assimilation and Growth of Trifolium subterraneum L. Using Dinitrogen or Ammonium Nitrate. PLANT PHYSIOLOGY 1982; 69:416-20. [PMID: 16662220 PMCID: PMC426221 DOI: 10.1104/pp.69.2.416] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The relative effects of water stress on growth parameters of subterranean clover (Trifolium subterraneum L. cv. Woogenellup) dependent on either N(2) or 8 millimolar NH(4)NO(3) for N were examined. Whole-plant carbon exchange rate (CER), acetylene reduction (AR), dry matter production, and Kjeldahl N accumulation were measured on uniform, intact swards of clover that were maintained under adequately watered conditions or were subjected to three cycles of water stress (leaf water potential </=-30 bar) over an 18-day period. In the absence or presence of water stress, growth rate, net N accumulation rate, and total N concentration of plants dependent on N(2) were 25 to 26, 45 to 50, and 20 to 21% less, respectively, than plants supplied with 8 millimolar NH(4)NO(3). The water stress treatment produced less than a 50% decrease in CER regardless of plant N source, a 90% inhibition of AR in plants dependent on N(2), and a 41% decline in dry matter production on both N sources. Water stress decreased reduced N accumulation 55% in N(2)-dependent plants and 50% in NH(4)NO(3)-dependent plants. Changes in growth and N accumulation caused a 10 to 11% decrease in total plant N concentration of water-stressed plants compared to adequately irrigated controls, but water stress decreased the N concentration of tissue synthesized during the 18-day treatment period in N(2)-grown plants more than in plants supplied 8 millimolar NH(4)NO(3). Thus, the relative effect of water stress on growth under the two N regimes was similar, but N accumulation by N(2)-dependent clover was inhibited to a slightly greater extent (P </= 0.001) than in NH(4)NO(3)-dependent plants.
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Affiliation(s)
- T M Dejong
- Department of Agronomy and Range Science, University of California, Davis, California 95616
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Imsande J, Ralston EJ. Hydroponic growth and the nondestructive assay for dinitrogen fixation. PLANT PHYSIOLOGY 1981; 68:1380-4. [PMID: 16662112 PMCID: PMC426107 DOI: 10.1104/pp.68.6.1380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Hydroponic growth medium must be well buffered if it is to support sustained plant growth. Although 1.0 millimolar phosphate is commonly used as a buffer for hydroponic growth media, at that concentration it is generally toxic to a soybean plant that derives its nitrogen solely from dinitrogen fixation. On the other hand, we show that 1.0 to 2.0 millimolar 2-(N-morpholino)ethanesulfonic acid, pK(a) 6.1, has excellent buffering capacity, and it neither interferes with nor contributes nutritionally to soybean plant growth. Furthermore, it neither impedes nodulation nor the assay of dinitrogen fixation. Hence, soybean plants grown hydroponically on a medium supplemented with 1.0 to 2.0 millimolar 2-(N-morpholino)ethanesulfonic acid and 0.1 millimolar phosphate achieve an excellent rate of growth and, in the absence of added fixed nitrogen, attain a very high rate of dinitrogen fixation. Combining the concept of hydroponic growth and the sensitive acetylene reduction technique, we have devised a simple, rapid, reproducible assay procedure whereby the rate of dinitrogen fixation by individual plants can be measured throughout the lifetime of those plants. The rate of dinitrogen fixation as measured by the nondestructive acetylene reduction procedure is shown to be approximately equal to the rate of total plant nitrogen accumulation as measured by Kjeldahl analysis. Because of the simplicity of the procedure, one investigator can readily assay 50 plants individually per day.
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Affiliation(s)
- J Imsande
- Department of Genetics, Iowa State University, Ames, Iowa 50011
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Patterson RP, Raper CD, Gross HD. Growth and Specific Nodule Activity of Soybean during Application and Recovery of a Leaf Moisture Stress. PLANT PHYSIOLOGY 1979; 64:551-6. [PMID: 16661008 PMCID: PMC543136 DOI: 10.1104/pp.64.4.551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Soybean plants growing at day/night temperatures of 30/18, 26/18, and 22/18 C were subjected to a single drying and recovery cycle during an 18- to 19-day period in the early to midpod development stage. Leaf total electrochemical water potential was reduced to about -24 bars during the 4-day drying cycle at all temperatures, but recovered to control levels upon rewatering. The changes in dry matter accumulation in whole plants and plant parts, specific activity of nodules as measured by acetylene reduction, and levels of adenosine phosphates in nodules were measured periodically during stress and recovery.Vegetative and reproductive growth were about equally suppressed by the leaf moisture stress. Both rate of appearance and number of pods were reduced. However, a similar average weight per pod for both stressed and control plants at the conclusion of the recovery period suggests that individual pod development is not irreversibly affected by a single stress cycle and that yield potential is restricted by a decrease in number of pods or seed. Dry matter accumulation in plants and pods was unaffected by temperature.Specific nodule activity and energy charge of nodules declined concurrently with leaf moisture potential. Recovery of specific nodule activity following rewatering lagged behind recovery of leaf moisture potential, but energy charge of nodules recovered as rapidly as leaf moisture potential upon rewatering. Thus, the delayed recovery of specific nodule activity does not appear to be related to recovery of energy charge of the nodules.
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Affiliation(s)
- R P Patterson
- Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27650
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Stovall I, Cole M. Organic Acid Metabolism by Isolated Rhizobium japonicum Bacteroids. PLANT PHYSIOLOGY 1978; 61:787-90. [PMID: 16660386 PMCID: PMC1091978 DOI: 10.1104/pp.61.5.787] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Rhizobium japonicum bacteroids isolated from soybean (Glycine max L.) nodules oxidized (14)C-labeled succinate, pyruvate, and acetate in a manner consistent with operation of the tricarboxylic acid cycle and a partial glyoxylate cycle. Substrate carbon was incorporated into all major cellular components (cell wall + membrane, nucleic acids, and protein).
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Affiliation(s)
- I Stovall
- Department of Agronomy, University of Illinois, Urbana, Illinois 61801
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Cowan M. The influence of nitrate, water potential and oxygen tension on nitrogen fixation in detached pea roots. ACTA ACUST UNITED AC 1978. [DOI: 10.1007/bf01093001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Sinclair AG, Hannagan RB, Johnstone P, Hardacre AK. Evaluation of a non-destructive acetylene reduction assay of nitrogen fixation for pasture legumes grown in pots. ACTA ACUST UNITED AC 1978. [DOI: 10.1080/03015521.1978.10426017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Mederski HJ, Streeter JG. Continuous, automated acetylene reduction assays using intact plants. PLANT PHYSIOLOGY 1977; 59:1076-81. [PMID: 16659997 PMCID: PMC542510 DOI: 10.1104/pp.59.6.1076] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An automated method was developed for continuous, in situ determination of acetylene reduction (N(2) fixation) by intact soybean plants (Glycine max [L.]). The culture vessel containing the roots of intact plants grown in sand culture is sealed at the surface and an air-acetylene mixture continuously injected into the root chamber. The effluent gas is automatically sampled and injected into a gas chromatograph. Continuous acetylene assay at intervals as short as 3.5 min may be made over a period of several days, without attention, except for plant watering. Adverse effects of prolonged exposure of the root system to acetylene were mitigated by pulse injection of acetylene for 20 min followed by 40 min of acetylene-free air. Bare root systems can be suspended in a reaction chamber and sprayed with water or nutrient solution; this permits periodic removal of the root system for sampling nodules.In studies lasting several diurnal cycles, acetylene reduction did not decline more than 50% of the maximum rate in light, thus nitrogenase activity depends on concomitant photosynthesis and on carbohydrate from storage pools.
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Affiliation(s)
- H J Mederski
- Department of Agronomy, Ohio Agricultural Research and Development Center, Wooster, Ohio 44691
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Huang CY, Boyer JS, Vanderhoef LN. Limitation of acetylene reduction (nitrogen fixation) by photosynthesis in soybean having low water potentials. PLANT PHYSIOLOGY 1975; 56:228-32. [PMID: 16659277 PMCID: PMC541794 DOI: 10.1104/pp.56.2.228] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The role of photosynthesis and transpiration in the desiccation-induced inhibition of acetylene reduction (nitrogen fixation) was investigated in soybean (Glycine max [L.] Merr. var. Beeson) using an apparatus that permitted simultaneous measurements of acetylene reduction, net photosynthesis, and transpiration. The inhibition of acetylene reduction caused by low water potentials and their aftereffects could be reproduced by depriving shoots of atmospheric CO(2) even though the soil remained at water potentials that should have favored rapid acetylene reduction. The inhibition of acetylene reduction at low water potentials could be partially reversed by exposing the shoots to high CO(2) concentrations. When transpiration was varied independently of photosynthesis and dark respiration in plants having high water potentials, no effects on acetylene reduction could be observed. There was no correlation between transpiration and acetylene reduction in the CO(2) experiments. Therefore, the correlation that was observed between transpiration and acetylene reduction during desiccation was fortuitous. We conclude that the inhibition of shoot photosynthesis accounted for the inhibition of nodule acetylene reduction at low water potentials.
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Affiliation(s)
- C Y Huang
- Departments of Botany and Agronomy, University of Illinois, Urbana, Illinois 61801
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