Abstract
Nodules of cowpea (Vigna unguiculata (L.) Walp. cv. Vita 3:Bradyrhizobium CB 756) from 28-d-old plants cultured for 23 d with their root systems maintained in O2 levels from 1 to 80% (v/v, in N2) in the external gas phase showed a range of structural changes which have been interpreted in relation to an over- or under-supply of O2. A response to the partial pressure of O2 in the gas phase (pO2) was noted with respect to nodule size, lenticel development, the relative distributions of cortical and infected central tissue, the differentiation of cortex, especially the inner cortex, the frequency and size of infected and uninfected interstitial cells, the volume of extracellular spaces both in cortex and infected tissue, and in the frequency of bacteroids. As a consequence of these changes the surface area of inner cortex relative to the nitrogenase-containing units of fixing tissue (infected cells or bacteroids) was increased by as much as 20-fold. Effectiveness of bacteroid functioning increased from 0.10 ± 0.02 · 10-9 μmol acetylene reduced per bacteroid in air-grown nodules to 0.9 ± 0.16 · 10-9 (same units) per bacteroid in those cultured in 1% O2.
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Abbreviations
- pO2 :
-
partial pressure of oxygen in the gas phase
References
Bergersen, F.J., Goodchild, D.J. (1973) Aeration pathways in soybean root nodules. Aust. J. Biol. Sci.26, 741–756
Carstensen, E.L., Donaldson, T.L., Miller, M.W., Law, W.K., Vives, B. (1981) Distribution of gas in the roots ofPisum sativum. Environ. Exp. Bot.21, 1–4
Dakora, F.D. (1990) Studies of nitrogen fixation, nitrogen assimilation and nodule development in grain legumes — Effects of O2. Ph.D. thesis, University of Western Australia, Nedlands
Dakora, F.D., Atkins, C.A. (1990a) Effect of pO2 on growth and nodule functioning of symbiotic cowpea (Vigna unguiculata L. Walp.). Plant Physiol.93, 948–955
Dakora, F.D., Atkins, C.A. (1990b) Effect of pO2 during growth on the gaseous diffusional properties of nodules of cowpea (Vigna unguiculata L. Walp.). Plant Physiol.93, 956–961
Dixon, R.O.D., Blunden, E.A.G., Searl, J.W. (1981) Intercellular space and hydrogen diffusion in pea and lupin root nodules. Plant Sci. Lett.23, 109–116
Frazer, H.L. (1942) The occurrence of endodermis in leguminous root nodules and its effect upon nodule function. Proc. R. Soc. Edinburgh B61, 328–343
Hunt, S., King, B.J., Canvin, D.T., Layzell, D.B. (1987) Steady and non-steady state gas exchange characteristics of soybean nodules in relation to the oxygen diffusion barrier. Plant Physiol.84, 164–172
Kaneko, Y., Newcomb, E.H. (1987) Cytochemical localisation of uricase and catalase in developing root nodules of soybean. Protoplasma140, 1–12
Minchin, F.R., Minguez, M.I., Sheehy, J.E., Witty, J.F., Skot, L. (1986) Relations between nitrate and oxygen supply in symbiotic nitrogen fixation by white clover. J. Exp. Bot.37, 1103–1113
Pankhurst, C.E., Sprent, J.I. (1975) Surface features of soybean root nodules. Protoplasma85, 85–98
Ralston, E.J., Imsande, J. (1982) Entry of oxygen and nitrogen into intact soybean nodules. J. Exp. Bot.33, 208–214
Sen, D., Weaver, R.W. (1984) A basis for different rates of N2-fixation by the same strains ofRhizobium in peanut and cowpea root nodules. Plant Sci. Lett.34, 239–286
Sen, D., Weaver, R.W., Bal, A.K. (1986) Structure and organisation of effective peanut and cowpea root nodules induced by rhizobial strain 32H1. J. Exp. Bot.37, 356–363
Sheehy, J.E., Thornley, J.H.M. (1988) Oxygen, theNifA gene, nodule structure and the initiation of nitrogen fixation. Ann. Bot. 61, 605–609
Sheehy, J.E., Minchin, F.R., Witty, J.F. (1983) Biological control of the resistance to oxygen flux to nodules. Ann. Bot.53, 13–20
Shelp, B.J., Atkins, C.A., Storer, P.J., Canvin, D.T. (1983) Cellular and sub-cellular organisation of pathways of ammonia assimilation and ureide synthesis in nodules of cowpea (Vigna unguiculata (L.) Walp.). Arch. Biochem. Biophys.224, 429–441
Spurr, A.R. (1969) A low viscosity epoxy resin embedding medium for electron microscopy. J. Ultrastruct. Res.26, 31–43
Tjepkema, J.D., Yocum, C.S. (1974) Measurement of oxygen partial pressure within soybean nodules by oxygen microelectrode. Planta119, 351–360
Tjepkema, J.D., Cartica, R.J. (1982) Diffusion limitation of oxygen uptake and nitrogenase activity in the root nodules ofParasponia rigida Merr. et Perry. Plant Physiol.69, 728–733
Webb, M.A., Newcomb, E.H. (1987) Cellular compartmentation of ureide biogenesis in root nodules of cowpea (Vigna unguiculata L. Walp.). Planta172, 162–175
Weibel, E.R. (1980) Stereological methods, vol. 2: Theoretical foundations. Academic Press, London New York
Weibel, E.R., Gomez, D.M. (1962) A principle for counting tissue structures on random sections. J. Appl. Physiol.17, 343–348
Weibel, E.R., Kistler, G.S., Scherle, W.F. (1966) Practical stereo-logical methods for morphometric cytology. J. Cell Biol.30, 23–38
Weisz, P.R., Sinclair, T.R. (1987a) Regulation of soybean nitrogen fixation in response to rhizosphere oxygen. I. Role of nodule respiration. Plant Physiol.84, 900–905
Weisz, P.R., Sinclair, T.R. (1987b) Regulation of soybean nitrogen fixation in response to rhizosphere oxygen. II. Quantification of nodule gas permebility. Plant Physiol.84, 906–910
Witty, J.F., Minchin, F.R., Skot, L., Sheehy, J.E. (1986) Nitrogen fixation and oxygen in legume root nodules. Oxford Surveys Plant Mol. Cell Biol.3, 275–314
Witty, J.F., Skot, L., Revsbech, N.P. (1987) Direct evidence for changes in the resistance of legume root nodules to oxygen diffusion. J. Exp. Bot.38, 1129–1140
Woolley, J.P. (1983) Maintenance of air in intercellular spaces of plants. Plant Physiol.72, 989–991
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This work was supported by a grant from the Australian Research Council (to C.A.A.) and an Australian International Development Assistance Bureau postgraduate fellowship (to F.D.D.). The authors wish to thank Dr. W.F.C. Blumer for his considerable help with morphometric analysis, Dr. J. Kuo for guidance in the use of histological techniques, and to Dr. J.S. Pate for the suggestion that lenticel development might be quantified by surface staining of nodules.
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Dakora, F.D., Atkins, C.A. Morphological and structural adaptation of nodules of cowpea to functioning under sub- and supra-ambient oxygen pressure. Planta 182, 572–582 (1990). https://doi.org/10.1007/BF02341034
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DOI: https://doi.org/10.1007/BF02341034