Abstract
Ultrastructural changes during zygotic and somatic embryogenesis in pearl millet (Pennisetum glaucum [L.] R. Br.) were quantified using morphometric techniques. The total area per cell profile and the cell volume percentage of the whole cell, endoplasmic reticulum (ER), Golgi bodies, mitochondria, nuclei, lipids, plastids, starch grains and vacuoles were measured and comparisons made between three zygotic and three somatic embryo developmental stages. All measurements were taken from scutellar or scutellar-derived cells. Zygotic embryogenesis was characterized by increases in cell size, lipids, plastids, starch, Golgi bodies, mitochondria and ER. Somatic embryogenesis was characterized by two phases of cell development: (1) the dedifferentiation of scutellar cells involving a reduction in cell and vacuole size and an increase in cell activity during somatic proembryoid formation and (2) the development of somatic embryos in which most cell organelle quantities returned to values found in late coleoptile or mature predesiccation zygotic stages. In summary, although their developmental pathways differed, the scutella of somatic embryos displayed cellular variations which were within the ranges observed for later stages of zygotic embryogenesis.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Barciela J, Vieitez AM (1993) Anatomical sequence and morphometric analysis during somatic embryogenesis on cultured cotyledon explants ofCamellia japonica L. Ann Bot 71:395–404
Bechtel DB, Pomeranz Y (1978) Ultrastructure of the mature ungerminated rice (Oryza sativa) caryopsis. The germ. Am J Bot 65:75–85
Bechtel DB, Gaines RL, Pomeranz Y (1982) Early stages in wheat endosperm formation and protein body initiation. Ann Bot 50:507–518
Dutta PC, Appelqvist L, Gunnarsson S, Hofsten A von (1991) Lipid bodies in tissue, somatic and zygotic embryo ofDaucus carota L.: a qualitative and quantitative study. Plant Sci 78:259–267
Emons AMC, Does H de (1993) Origin and development of embryo and bud primordia during maturation of embryogenic calli ofZea mays. Can J Bot 71:1349–1356
Emons AMC, Kieft H (1991) Histological comparison of single somatic embryos of maize from suspension culture with somatic embryos attached to callus cells. Plant Cell Rep 10:485–488
Flinn BS, Webb DT, Newcomb W (1989) Morphometric analysis of reserve substances and ultrastructural changes during caulogenic determination and loss of competence of eastern white pine (Pinus strobus) cotyledons in vitro. Can J Bot 67:779–789
Fransz PF, Schel JHN (1987) An ultrastructural study on the early callus development from immature embryos of the maize strains A188 and A632. Acta Bot Neerl 36:247–260
Fransz PF, Schel JHN (1991a) Cytodifferentiation during the development of friable embryogenic callus of maize (Zea mays). Can J Bot 69:26–33
Fransz PF, Schel JHN (1991b) An ultrastructural study on the early development ofZea mays somatic embryos. Can J Bot 69:858–865
Fransz PF, Schel JHN (1994) Ultrastructural studies on callus development and somatic embryogenesis inZea mays L. In: Bajaj YPS (ed) Biotechnology in agriculture and forestry. (Maize vol 25) Springer, New York Heidelberg Berlin, pp 50–65
Fransz PF, Kieft H, Schel JHN (1990) Cell cycle during callus initiation from cultured maize embryos. An autoradiographic study. Acta Bot Neerl 39:65–73
Jones TJ, Rost TL (1989a) Histochemistry and ultrastructure of rice (Oryza sativa) zygotic embryogenesis. Am J Bot 76:504–520
Jones TJ, Rost TL (1989b) The developmental anatomy and ultrastructure of somatic embryos from rice (Oryza sativa L.) scutellum epithelial cells. Bot Gaz 150:41–49
Krochko J, Bantroch DJ, Greenwood JS, Bewley JD (1994) Seed storage proteins in developing somatic embryos of alfalfa: defects in accumulation compared to zygotic embryos. J Exp Bot 45:699–708
Mangat BS, Pelekis MK, Cassells AC (1990) Changes in starch content during organogenesis in in vitro culturedBegonia rex stem explants. Physiol Plant 79:267–274
Maquoi E, Hanke DE, Deltour R (1993) The effects of abscisic acid on the maturation ofBrassica napus somatic embryos. Protoplasma 174:147–157
Murashige T, Skoog F (1962) A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol Plant 15:473–497
Nickle TC, Yeung EC (1993) Failure to establish a functional shoot meristem may be a cause of conversion failure in somatic embryos ofDaucus carota (Apiaceae). Am J Bot 80:1284–1291
Nickle TC, Yeung EC (1994) Further evidence of a role for abscisic acid in conversion of somatic embryos ofDaucus carota. In Vitro Cell Dev Biol 30P:96–103
Nieuwdorp PJ (1963) 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
Nieuwdorp PJ, Buys MC (1964) Electron microscopic structure of the epithelial cells of barley. II. Cytology of the cells during germination. Acta Bot Need 13:559–565
Redway FA (1991) Histology and stereological analysis of shoot formation in leaf callus ofSaintpaulia ionantha Wendl (African violet). Plant Sci 73:243–251
Reynolds RL (1984) An ultrastructural and stereological analysis of pollen grains ofHyoscyamus niger during normal ontogeny and induced embryogenic development. Am J Bot 71:490–504
Taylor MG, Vasil IK (1995) The ultrastructure of zygotic embryo development in pearl millet (Pennisetum glaucum; Poaceae). Am J Bot 82:205–219
Taylor MG, Vasil IK (1996) The ultrastructure of somatic embryo development in pearl millet (Pennisetum glaucum; Poaceae). Am J Bot 83:28–44
Toth R (1982) An introduction to morphometric cytology and its application to botanical research. Am J Bot 69:1694–1706
Van Lammeren AAM (1986) Developmental morphology and cytology of the young maize embryo (Zea mays L.). Acta Bot Neerl 35:169–188
Vasil IK (1994) Molecular improvement of cereals. Plant Mol Biol 25:925–937
Vasil IK (1995) Cellular and molecular genetic improvement of cereals. In: Terzi M, Cella R, Falavigna A (eds) Current issues in plant molecular and cellular biology. Kluwer, Dordrecht, pp 5–18
Weibel ER (1979) Stereological methods. (Practical methods for biological morphometry, vol 1) Academic Press, New York
Williams MA (1977) Quantitative methods in biology. In: Glauert AM (ed) Practical methods in electron microscopy, vol 6. Elsevier, New York, pp 1–234
Zeleznak K, Varriano-Marston E (1982) Pearl millet (Pennisetum americanum (L.) Leeke) and grain sorghum (Sorghum bicolor (L.) Moench) ultrastructure. Am J Bot 69:1306–1313
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Taylor, M.G., Vasil, I.K. Quantitative analysis of ultrastructural changes during zygotic and somatic embryogenesis in pearl millet (Pennisetum glaucum [L.] R. Br.). Sexual Plant Reprod 9, 286–298 (1996). https://doi.org/10.1007/BF02152704
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02152704