Abstract
The ultrastructure of the scutellum and the aleurone layer has been examined in seeds of Nordal barley following malting for 0, 30, 72, 120 and 162 hours at 15°C. Thick sections from the seeds were stained with Calcofluor White M2R New and examined in the light microscope to determine the extent of cell wall degradation in the endosperm.
The changes in the scutellar parenchyma cells include degradation of the protein bodies and the appearance of vacuoles and prominent amyloplasts. The analysis of a serially sectioned epithelial cell from the scutellum 72 hours after the start of malting revealed a large number of Golgi apparatuses, preferentially located near the cell wall. It is suggested that the presence and location of the Golgi apparatuses are related to enzyme secretion. Following malting for 72 hours or more, the epithelial cells contain lomasomes and membrane aggregates, termed membrane bodies. The analysis indicated that lomasomes originate from the membrane bodies and are involved in the growth of the cell walls of the epithelium. Organelles indicating cellular activity, i.e., rough endoplasmic reticulum, mitochondria and Golgi apparatuses, first appear in the epithelial cells of the scutellum, and later in the cells of the aleurone layer. Furthermore, the degradation of the endosperm starts in the vicinity of the scutellum as judged by the calcofluor staining. Therefore, it is concluded that the scutellar epithelium provides the enzymes during the initial degradation of the endosperm. In seeds malted for 162 hours, aleurone cells with a cytoplasmic organisation indicative of active metabolism are located in the embryo part of the seed, whereas aleurone cells adjacent to unmodified endosperm in the distal end of the same seed show little or no structural sign of activity.
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Aastrup, S. &K. Erdal: Quantitative determination of endosperm modification and its relationship to the content of 1,3∶1,4-β-glucans during malting of barley. Carlsberg Res. Commun. 45, 369–379 (1980)
Briggs, D. E.: Development of enzymes by barley embryos in vitro. J. Inst. Brew 68, 470–475 (1962)
Briggs, D. E.: Origin and distribution, of α-amylase in malt. J. Inst. Brew. 70, 14–24 (1964)
Briggs, D. E.: α-amylase in germinating decorticated barley—I. α-amylase, conditions of growth and grain constituents. Phytochemistry 7. 513–529 (1968)
Briggs, D. E.: Enzyme formation, cellular breakdown and the distribution of gibberellins in the endosperm of barley. Planta 108, 351–358 (1972)
Briggs, D. E. &V. J. Clutterbuck: Generation of α-amylase in germinating Hordeum distichon. Phytochemistry 12, 1047–1050 (1973)
Brown, H. T. &G. H. Morris: Researches on the germination of some of the gramineæ. J. Chem. Soc. 57, 458–528 (1890)
Buttrose, M. S.: Ultrastructure of barley aleurone cells as shown by freeze-etching. Planta 96, 13–26 (1971)
Domozych, D. S., K. D. Stewart &K. R. Mattox: Development of the cell wall in Tetraselmis: Role of the Golgi apparatus and extracellular wall assembly. J. Cell Sci. 52, 351–371 (1981)
Eb, van der A. A. &P. J. Nieuwdorp: Electron microscopic structure of the aleurone cells of barley during germination. Acta Bot. Neerl. 15, 690–699 (1967)
Gibbons, G. C.: On the localisation and transportation of α-amylase during germination and early seedling growth of Hordeum vulgare. Carlsberg Res. Commun. 44, 353–366 (1979)
Gibbons, G. C.: On the sequential determination of α-amylase transport and cell wall breakdown in germinating seeds of Hordeum vulgare. Carlsberg Res. Commun. 45, 177–184 (1980)
Groat, J. I. &D. E. Briggs: Gibberellins and α-amylase formation in germinating barley. Phytochemistry 8, 1615–1627 (1969)
Haberlandt, G.: Die Kleberschicht des Grasendospermes als Diastase ausscheidendes Drüsen Gewebe. Ber. Deutsch. Bot. Gesell. 8, 40–48 (1890)
Jacobsen, J. V. &R. B. Knox: Cytochemical localization and antigenicity of α-amylase in barley aleurone tissue. Planta 112, 213–224 (1973)
Jacobsen, J. V., R. B. Knox &N. A. Pyliotis: The structure and composition of aleurone grains in the barley aleurone layer. Planta 101, 189–209 (1971)
Jacobsen, J. V. &J. E. Varner: Gibberellic acid-induced synthesis of protease by isolated aleurone layers of barley. Plant Physiol. 42, 1596–1600 (1967)
Jones, R. L.: The fine structure of barley aleurone cells. Planta 85, 359–375 (1969)
Jones, R. L.: Gibberellic acid, and the fine structure of barley aleurone cells. I. Changes during the lag-phase of α-amylase synthesis. Planta 87, 119–133 (1969)
Jones, R. L.: Gibberellic acid and the fine structure of barley aleurone cells. II. Changes during the synthesis and secretion of α-amylase. Planta 88, 73–86 (1969)
Jones, R. L.: Fractionation of the enzymes of the barley aleurone layer: Evidence for a soluble mode of enzyme release. Planta 103, 95–109 (1972)
Jones, R. L.: Quantitative and qualitative changes in the endoplasmic reticulum of barley aleurone layers. Planta 150, 70–81 (1980)
Jones, R. L. &C. Ru-fang: Immunohistochemical localization of α-amylase in barley aleurone cells. J. Cell Sci. 20, 183–198 (1976)
Kirsop, B. H. &J. R. A. Pollock: Studies in barley and malt. XII. Interaction between the embryo and the endosperm of barley during malting. J. Inst. Brew. 64, 227–233 (1958)
Locy, R. &H. Kende: The mode of secretion of α-amylase in barley aleurone layers. Planta 143, 89–99 (1978)
MacLeod, A. M. &G. H. Palmer: The embryo of barley in relation to modification of the endosperm. J. Inst. Brew. 72, 580–589 (1966)
Mollenhauer, H. H. &D. J. Morré: Golgi apparatus and plant cell secretion. Ann. Rev. Pl. Physiol. 17, 27–46 (1966)
Nieuwdorp, P. J.: Electron microscopic structure of the epithelial cells of the scutellum of barley. The structure of the epithelial cells before germination. Acta Bot. Neerl. 12, 295–301 (1963)
Nieuwdorp, P. J. &M. C. Buys: Electron microscopic structure of the epithelial cells of the scutellum of barley. II. Cytology of the cells during germination. Acta Bot. Neerl. 13, 559–565 (1964)
O'Brien, J. A.: Cytoplasmic inclusions in the glandular epithelium of the scutellum of Triticum aestivum and Secale cereale. Am. J. Bot. 29, 479–491 (1942)
Okamoto, K., H. Kitano &T. Akazawa: Biosynthesis and excretion of hydrolases in germinating cereal seeds. Plant and Cell Physiol. 21, 201–204 (1980)
Paleg, L. G.: Physiological effects of gibberellic acid. II. On starch hydrolyzing enzymes of barley endosperm. Plant Physiol. 35, 902–906 (1960)
Paleg, L. G. &B. Hyde: Physiological effects of gibberellic acid. VII. Electron microscopy of barley aleurone cells. Plant Physiol. 39, 673–680 (1964)
Radley, M.: Site of production of gibberellin-like substances in germinating barley embryos. Planta 75, 164–171 (1967)
Smart, M. G. &T. P. O'Brien: Observations on the scutellum. I. Overall development during germination in four grasses. Austr. J. Bot. 27, 391–401 (1979)
Spurr, A. R.: A low-viscosity epoxy resin embedding medium for electron microscopy. J. Ultrastruct. Res. 26, 31–43 (1969)
Swift, J. G. &T. P. O'Brien: The fine structure of the wheat scutellum before germination. Austr. J. Biol. Sci. 25, 9–22 (1972)
Swift, J. G. &T. P. O'Brien: The fine structure of the wheat scutellum during germination. Austr. J. Biol. Sci. 25, 469–486 (1972)
Varner, J. E.: Gibberellic acid controlled synthesis of α-amylase in barley endosperm. Plant Physiol. 39, 413–415 (1964)
Vigil, E. L. &M. Ruddat: Effect of gibberellic acid and actinomycin D on the formation and distribution of rough endoplasmic reticulum in barley aleurone cells. Plant Physiol. 51, 549–558 (1973)
Whaley, W. G.: The Golgi apparatus. Cell Biol. Monogr. Vol. 2, Springer Verlag, Vienna and New York. (1975))
Whaley, W. G. &M. Dauwalder: The Golgi apparatus, the plasma membrane and functional integration. Int. Rev. Cytol. 58, 199–245 (1979)
Wood, P. J. &R. G. Fulcher: Interaction of some dyes with cereal β-glucans. Cereal Chem. 55, 952–966 (1978)
Yomo, H. &H. Iinuma: Production of gibberellin-like substance in the embryo of barley during germination. Planta 71, 113–118 (1966)
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Gram, N.H. The ultrastructure of germinating barley seeds. I. Changes in the scutellum and the aleurone layer in Nordal barley. Carlsberg Res. Commun. 47, 143–164 (1982). https://doi.org/10.1007/BF02914032
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DOI: https://doi.org/10.1007/BF02914032