Summary
The male germ unit ofPetunia hybrida was examined quantitatively and qualitatively at the ultrastructutral level. Three-dimensional reconstructions, the determination of nuclear and cytoplasmic volumes and surface areas, and organelle counts were obtained from serial ultrathin sections and computer analysis. In the mature pollen grain, an elongated generative cell is found in direct physical association with and partially surrounded by the vegetative nucleus. The mature generative cell lacks plastids and has mitochondria equally distributed at both of its tapering ends. In the pollen tube, the sperm cells are physically associated by cytoplasmic connections to each other and to the surrounding vegetative cell membrane. At full style length, the lobed vegetative nucleus and sperm pair are found in close association near the end of the pollen tube. The two sperms of a pair are not strongly dimorphic.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Clauhs RP, Grun P (1977) Changes in plastid and mitochondrion content during maturation of generative cells ofSolanum (Solanaceae). Am J Bot 64: 377–383
Ciampolini F, Cresti M (1977) Main ultrastructural features ofPetunia hybrida pollen tube. Caryologia 30: 487–488
Cresti M, Ciampolini F, Kapil RN (1985 a) Generative cells of some angiosperms with particular emphasis on their microtubules. J Submicrosc Cytol 16: 317–326
——,Mulcahy DLM, Mulcahy G (1985 b) Ultrastructure ofNicotiana alata pollen, its germination and early tube formation. Am J Bot 72: 719–727
— —,Pacini Sarfatti, G., van Went, J. L., Willemse, M. T. M. (1979) Ultrastructural differences between compatible and incompatible pollen tubes in the stylar transmitting tissue ofPetunia hybrida. J. Submicros Cytol11: 209–219
—,Pacini, E., Ciampolini F, Sarfatti G (1977) Germination and early tube developmentin vitro ofLycopersicum peruvianum pollen: Ultrastructural features. Planta 136: 239–247
Dumas C, Knox RB, Gaude T (1985) The spatial association of the sperm cells and vegetative nucleus in the pollen grain ofBrassica. Protoplasma 124, 168–174
— —,McConchie CA, Russell SD (1984) Emerging physiological concepts in fertilization. What's New Plant Phys 15: 17–20
Galey FR, Nilsson SEG (1966) A new method for transferring sections from the liquid surface of the trough through staining solution to the supporting film of a grid. J Ultrastruct Res 14: 405–410
Herrero M, Dickinson H (1981) Pollen tube development inPetunia hybrids following compatible and incompatible interspecific matings. J Cell Sci 47: 365–383
Heslop-Harrison J, Heslop-Harrison Y (1984) The disposition of gamete and vegetative-cell nuclei in the extending pollen tubes of a grass species,Alopecurus pratensis. Acta Bot Neerl 33: 131–134
—,Heslop-Harrison JS, Heslop-Harrison Y (1986) The comportment of the vegetative nucleus and generative cell in the pollen and pollen tubes ofHelleborus foetidus. Ann Bot 58: 1–12
Hu SY, Zhu C, Xu L (1981) Ultrastructure of male gametophyte in wheat: 2. Formation and development of sperm cell. Acta Bot Sin 23: 85–91
Jensen WA, Fisher DB (1968) Cotton embryogenesis: The sperm. Protoplasma 65: 277–286
—— (1970) Cotton embryogenesis: The pollen tube in the stigma and style. Protoplasma 69: 215–235
Juniper BE, Cox GC, Gilchrist AJ, Williams PR (1970) Techniques for plant electron microscopy. Blackwell Sci Publ Oxford, England
Karas I, Cass DD (1976) Ultrastructural aspects of sperm cell formation in rye: evidence for cell plate involvement in generative cell division. Phytomorphology 26: 36–45
Kaul V, Theunis C, Palser B, Knox RB, Williams E (1987) Association of the generative cell and vegetative nucleus in pollen tubes ofRhododendron. Ann Bot 59: 227–235
Kroh M, (1967) Fine structure ofPetunia pollen germinated “in vivo”. Rev Paleobot Palyn 3: 197–203
Larson DA (1965) Fine-structural changes in the cytoplasm of germinating pollen. Am J Bot 52: 139–154
Levieil C (1986) Évolution de l'association des cellules mâles dans le tube pollinique et dans le sac embryonnaire chez Cichorium intybus L. CR Acad Sci Paris 303: 769–774
McConchie CA, Jobson S, Knox RB (1984) Analysis of the ultrastructure of sperm cells ofBrassica campestris by computer-assisted three-dimensional reconstruction. In:Williams EG, Knox RB (eds) Pollination '84. U. Melbourne Press, Melbourne, pp 26–29
—, (1985) Computer-assisted reconstruction of the male germ unit in pollen ofBrassica campestris. Protoplasma 127: 57–63
—,Knox RB (1986) Organization of the male germ unit inBrassica campestris and corn. In:Mulcahy DL, Mulcahy GB, Ottaviano E (eds) Biotechnology and ecology of pollen. Springer, Wien New York, pp 289–296
—,Russell SD, Dumas C, Tuchy M, Knox RB (1987) Quantitative cytology of the sperms ofBrassica campestris andB. oleracea. Planta 170: 446–452
Moens PB, Moens T (1981) Computer measurements and graphics of three-dimensional cellular ultrastructure. J Ultrastruct Res 75: 131–141
Mogensen HL (1971) A modified method for re-embedding thick epoxy sections for ultramicrotomy. J Ariz Acad Sci 6: 249–250
— (1986 a) On the male germ unit in an angiosperm with bicellular pollen,Hippeastrum vitatum. In:Mulcahy DL, Mulcahy GB, Ottaviano E (eds) Biotechnology and ecology of pollen. Springer, Wien New York, pp 297–305
— (1986 b) Preliminary observations on the three-dimensional organization of the wheat sperm cell. In: Pollination '86. U. Melbourne Press, Melbourne, pp 166–171
Mogensen HL, Rusche ML (1985) Quantitative ultrastructural analysis of barley sperm. 1. Occurrence and mechanism of cytoplasm and organelle reduction and the question of sperm dimorphism. Protoplasma 128: 1–13
—,Wagner, VT (1987) Associations among components of the male germ unit following in vivo pollination in barley. Protoplasma 138: 161–172
Russell SD (1984) Ultrastructure of the sperm ofPlumbago zeylanica. II. Quantitative cytology and three-dimensional organization. Planta 162: 385–391
— (1986) Dimorphic sperm cells, cytoplasmic transmission, and preferential fertilization inPlumbago zeylanica. In:Mantell SH, Chapman GP, Street PFS (eds) The condriome. Longman, London, pp 69–116
—,Cass DD (1981) Ultrastructure of the sperms ofPlumbago zeylanica. 1. Cytology and association with the vegetative nucleus. Protoplasma 107: 85–107
Sassen MMA (1964) Fine structure ofPetunia pollen grain and pollen tube. Acta Bot Neerl 13: 175–181
Schröder MB (1983) The ultrastructure of sperm cells inTriticale. In:Erdelska O (ed) VEDA, Bratislava, pp 101–104
Spurr AR (1969) A new low viscosity epoxy resin embedding medium for electron microscopy. J Ultrastruct Res 26: 31–43
Vaughn KC (1981) Organelle transmission in higher plants: organelle alteration vs. physical exclusion. J Heredity 72: 335–337
Vodopich DS andMoore R (1984) A computer program to facilitate morphometric analyses of cellular ultrastructure. TSEM 15: 9–10
Wagner VT (1986) The male germ unit in the pollen grain and tube ofPetunia hybrida. MS thesis. Northern Arizona University Library, Flagstaff, AZ
Wilms HJ (1984) Behavior of spinach sperm cells in pollen tubes prior to fertilization. In:Willemse MTM, van Went JL (eds) Proceedings of the 8th International Symposium on Sexual Reproduction in Seed Plants, Ferns and Mosses. Pudoc Wageningen, Netherlands, pp 143–144
— (1986) Dimorphic sperm cell in the pollen grain ofSpinacia. In:Cresti M, Dallai R (eds) Biology of reproduction and cell motility in plants and animals. University of Siena, Siena, pp 193–198
—,van Aelst AC (1983) Ultrastructure of spinach sperm cells in mature pollen. In:Erdelska O (ed) Fertilization and embryogenesis in ovulated plants. VEDA, Bratislava, pp 105–112
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Wagner, V.T., Mogensen, H.L. The male germ unit in the pollen and pollen tubes ofPetunia hybrida: Ultrastructural, quantitative and three-dimensional features. Protoplasma 143, 101–110 (1988). https://doi.org/10.1007/BF01291154
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01291154