Abstract
The structural details of membrane organization in germinating and senescing cotyledons of cowpea (Vigna unguiculata (L.) Walp.) were studied by thin section and freeze-fracture electron microscopy. Germination- and senescence-related changes in the ultrastructure of parenchymal cells of cowpea cotyledons, as detected in thin sections, closely resemble those described for other leguminous seeds. Additionally, electron-dense deposits associated with the membranes, particularly the plasmalemma and endoplasmic reticulum, were seen to increase with advancing senescence. Freeze-fracture electron microscopy demonstrated that the membranes of cotyledons of 2-d-old seedings appear to be normal, with evenly dispersed intramembranous particles. However by 4 d, small areas or domains of the plasmalemma were free of intramembranous particles. These particle-free areas increased in both size and number as senescence progressed. We interpret these particle-free areas to be structural evidence for lateral phase separations of the membrane lipids into microdomains of gel-phase lipid from which intrinsic membrane proteins are excluded. Our results support wide-angle X-ray diffraction studies which have demonstrated the presence of gel-phase lipids in senescing bean cotyledons.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- EF:
-
exoplasmic fracture
- ER:
-
endoplasmic reticulum
- ESR:
-
electron-spin resonance
- IMP(s):
-
intramembranous particle(s)
- PF:
-
protoplasmic fracture
References
Ashton, F.M. (1976) Mobilization of storage proteins of seeds. Annu. Rev. Plant Physiol. 27, 95–117
Bain, J.M., Mercer, F.V. (1966) Subcellular organization of the cotyledons in germinating seeds and seedlings of Pisum sativum L. Aust. J. Biol. Sci. 19, 69–84
Barber, R.F., Thompson, J.E. (1980) Senescence-dependent increase in the permeability of liposomes prepared from bean cotyledon membranes. J. Exp. Bot. 31, 1305–1313
Barber, R.F., Thompson, J.E. (1983) Neutral lipids rigidify unsaturated acyl chains in senescing membranes. J. Exp. Bot. 34, 268–276
Branton, D., Bullivant, S., Gilula, N.B., Karnovsky, M.J., Moore, H., Muhlethaler, K., Northcote, D.H., Packer, L., Satir, B., Satir, P., Speth, V., Staehelin, L.A., Steere, R.L., Weinstein, R.S. (1975) Freeze-etching nomenclature. Science 190, 54–56
Chia, L.S., Thompson, J.E., Dumbroff, E.B. (1981) Simulation of the effects of leaf senescence on membranes by treatment with paraquat. Plant Physiol. 67, 415–420
Ferguson, C.H.R., Simon, E.W. (1973) Membrane lipids in senescing green tissues. J. Exp. Bot. 24, 307–316
Hackenbrock, C.R., Höchli, M., Chau, R.M. (1976) Colorimetric and freeze fracture analysis of lipid phase transitions and lateral translational motion of intramembrane particles in mitochondrial membranes. Biochim. Biophys. Acta 455, 466:484
Haest, C.W.M., Verkleij, A.J., DeGier, J., Scheek, R., Ververgaert, P.H.J., Van Deenen, L.L.M. (1974) The effect of lipid phase transitions on the architecture of bacterial membranes. Biochim. Biophys. Acta 356, 17–26
Haest, C.W.M., DeGier, J., Van Es, G.A., Verkleij, A.J., Van Deenen, L.L.M. (1972) Fragility of the permeability barrier of Escherichia coli. Biochim. Biophys. Acta 288, 43–53
Harris, N., Chrispeels, M.F. (1980) The endoplasmic reticulum of mung bean cotyledons: quantitative morphology of cisternal and tubular ER during seedling growth. Planta 148, 293–303
Lees, G.L., Thompson, J.E. (1980) Lipid composition and molecular organization in plasma membrane-enriched fractions from senescing cotyledons. Physiol. Plant. 49, 215–221
Legge, R.L., Thompson, J.E., Murr, D.P., Tsujita, M.J. (1982) Sequential changes in lipid fluidity and phase properties of microsomal membranes from senescing rose petals. J. Exp. Bot. 33, 303–312
McKersie, B.D., Lepock, J.R., Kruuv, J., Thompson, J.E. (1978) The effects of cotyledon senescence on the composition and physical properties of membrane lipid. Biochim. Biophys. Acta 508, 197–212
McKersie, B.D., Thompson, J.E. (1977) Lipid crystallization in senescent membranes from cotyledons. Plant Physiol. 59, 803–807
McKersie, B.D., Thompson, J.E. (1979) Phase properties of senescing plant membranes. Role of neutral lipids. Biochim. Biophys. Acta 550, 48–58
McKersie, B.D., Thompson, J.E., Brandon, J.K. (1976) X-ray diffraction evidence for decreased lipid fluidity in senescent membranes from cotyledons. Can. J. Bot. 54, 1074–1078
Moeller, C.H., Mudd, J.B., Thomson, W.W. (1981) Lipid phase separations and intramembranous particle movements in the yeast tonoplast. Biochim. Biophys. Acta 643, 376–386
Öpik, H. (1966) Changes in cell fine structure in the cotyledons of Phaseolus vulgaris L. during germination. J. Exp. Bot. 17, 427–439
Papahadjopoulos, D.M., Jacobson, K., Nir, S., Isac, T. (1973) Phase transition in phospholipid vesicles. Fluorescence polarization and permeability measurements concerning the effect of temperature and cholesterol. Biochim. Biophys. Acta 311, 330–348
Platt-Aloia, K.A., Thomson, W.W., Bliss, R.D. (1983) Lipid-lipid interactions and membrane fusion in plant salt glands. In: Biosynthesis and function of plant lipids (Proc. 6th Ann. Symp. in Bot., Riverside), pp. 160–172, Thomson, W.W., Mudd, J.B., Gibbs, M., eds. Waverly Press, Baltimore, Maryland
Platt-Aloia, K.A., Thomson, W.W. (1982) Freeze fracture of intact plant tissue. Stain Technol. 57, 327–334
Reynolds, E.S. (1963) The use of lead citrate at high pH as an electron opaque stain in electron microscopy. J. Cell Biol. 17, 208–212
Shechter, E., Letellier, L., Gulik-Kuzywiki, T. (1974) Relations between structure and function in cytoplasmic membrane vesicles isolated from an E. coli fatty acid auxotroph. Eur. J. Biochem. 49, 61–76
Shimshick, E.J., McConnell, H.M. (1973) Lateral phase separation in phospholipid membranes. Biochemistry 12, 2351–2360
Spurr, A.R. (1969) A low-viscosity epoxy resin embedding medium for electron microscopy. J. Ultrastruct. Res. 26, 31–43
Thompson, J.E. (1974) The behavior of cytoplasmic membranes in Phaseolus vulgaris cotyledons during germination. Can. J. Bot. 52, 534–541
Thompson, J.E., Mayfield, C.I., Inniss, W.E., Butler, D.E., Kruuv, J. (1978) Senescence-related changes in the lipid transition temperature of microsomal membranes from algae. Physiol. Plant. 43, 114–120
Wunderlich, F., Ronai, A., Speth, V., Seelig, J., Blume, A. (1975) Thermotropic lipid clustering in Tetrahymena membranes. Biochemistry 14, 3730–3735
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Platt-Aloia, K.A., Thomson, W.W. Freeze-fracture evidence of gel-phase lipid in membranes of senescing cowpea cotyledons. Planta 163, 360–369 (1985). https://doi.org/10.1007/BF00395144
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00395144