Summary
Facultative heterochromatin occurs not only in certain animals in connection with sex determination but also in members of at least one plant genus,Gagea (Liliaceae s. str.), but here in the course of embryo sac development, fertilization, and endosperm formation. The present contribution intends to provide undebatable photographic and cytometric evidence, previously not available, for the events in the course of which three whole genomes in the pentaploid endosperm nuclei ofGagea lutea become heterochroma-tinized. In this plant, embryo sac formation usually follows the Fritillaria type, i.e., the embryo sac is tetrasporic, and a “1 + 3 position” of the spore nuclei is followed by a mitosis in which the three chalazal spindles fuse and two triploid nuclei are formed. A triploid chalazal polar nucleus is derived from one of these, which contributes to the pentaploid endosperm. These nuclei in the chalazal part of the embryo sac show stronger condensation compared with the micropylar ones. The pycnosis of the triploid polar nucleus is maintained and even enhanced during endosperm proliferation, while the micropylar polar nucleus and the sperm nucleus maintain their euchromatic condition. The origin of the heterochromatic masses in the endosperm nuclei from the three chalazal genomes of the central cell is unambiguously evident from the distribution of heterochromatic chromosomes in the first endosperm mitosis and the following interphase. DNA content measurements confirm a 3 ∶ 2 relationship of heterochromatic and euchromatic chromosome sets, which is usually maintained up to the cellularized endosperm. Pycnotic nuclei in the chalazal part of megagametophytes are characteristic of several embryo sac types, but only forGagea spp. it is documented that such nuclei can take part in fertilization and endosperm formation.
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References
Baranyi M, Greilhuber J (1996) Flow cytometric and Feulgen den-sitometric analysis of genome size variation inPisum. Theor Appl Genet 92: 297–307
Barr ML, Bertram EG (1949) A morphological distinction between neurones of the male and female, and the behaviour of the nucleolar satellite during accelerated nucleoprotein synthesis. Nature 163: 676–677
Belyaev ND, Keohane AM, Turner BM (1996) Differential underacetylation of histones H2A, H3 and H4 on the inactive X chromosome in human female cells. Hum Genet 97: 573–578
Brown SW (1966) Heterochromatin. Science 151: 417–425
—, Nur U (1964) Heterochromatic chromosomes in the coccids. Science 145: 130–136
Bužek J, Ebert I, Ruffini-Castiglione M, Široký J, Vyskot B, Greilhuber J (1998a) Structure and DNA methylation pattern of partially heterochromatinised endosperm nuclei inGagea lutea (Liliaceae). Planta 204: 506–514
—, Riha K, Široký J, Ebert I, Greilhuber J, Vyskot B (1998b) Histone H4 underacetylation in plant facultative heterochromatin. Biol Chem 379: 1235–1241
Carmichael JS, Friedman WE (1995) Double fertilization inGnetum gnemon: the relationship between the cell cycle and sexual reproduction. Plant Cell 7: 1975–1988
Darlington CD (1947) Nucleic acids and the chromosomes. Symp Soc Exp Biol 1: 252–269
Dimitrova D, Ebert I, Greilhuber J, Kozhuharov S (1999) Karyotype constancy and genome size variation in BulgarianCrepis foetida s.l. (Asteraceae). Plant Syst Evol 217: 245–257
Friedman WE (1991) Double fertilization inEphedra trifurca, a non-flowering seed plant: the relationship between fertilization events and the cell cycle. Protoplasma 165: 106–120
— (1999) Expression of the cell cycle in sperm ofArabidopsis: implications for understanding patterns of gametogenesis and fertilization in plants and other eukaryotes. Development 126: 1065–1075
Geitler L (1950) Notizen zur endomitotischen Polyploidisierung in Trichocyten und Elaiosomen sowie über die Kernstrukturen beiGagea lutea. Chromosoma 3: 271–281
— (1963) Morphologie und Entwicklungsgeschichte der Zelle. Fortschr Bot 25: 1–12
Greilhuber J (1973) Über die Entwicklung des Embryosacks vonMelampyrum undParentucellia latifolia (Scrophulariaceae, Pedicularieae). Oesterr Bot Z 121: 81–97
— (1988) “Self-tanning”: a new and important source of stoichio-metric error in cytophotometric determination of nuclear DNA content in plants. Plant Syst Evol 158: 87–96
—, Ebert I (1994) Genome size variation inPisum sativum. Genome 37: 646–655
Heitz E (1933) Die Herkunft der Chromocentren. Planta 18: 571–636
Herr JM Jr (1971) A new clearing-squash technique for the study of ovule development in angiosperms. Am J Bot 58: 785–790
Jeppesen P, Turner BM (1993) The inactive X chromosome in femal mammals is distinguished by a lack of histone H4 acetylation, a cytogenetic marker for gene expression. Cell 74: 281–289
John B (1988) The biology of heterochromatin. In: Verma RS (ed) Heterochromatin. Cambridge University Press, Cambridge, pp 1–147
Johri BM (1936) Studies in the family Alismataceae 4:Alisma plantago L.,A. plantago-aquatica L. andSagittaria graminea Mich. Proc Ind Acad Sci B 4: 128–138
—, Ambegaokar KB, Srivastava PS (1992) Comparative embryology of angiosperms. Springer, Berlin Heidelberg New York Tokyo
König C, Ebert I, Greilhuber J (1987) A DNA cytophotometric and chromosome banding study inHedera helix (Araliaceae), with reference to differential DNA replication associated with juvenile-adult phase change. Genome 29: 498–503
Lyon MF (1961) Gene action in the X-chromosome of the mouse (Mus musculus L.). Nature 190: 372–373
Maheshwari P (1946) TheFritillaria type of embryo-sac: a critical review. J Ind Bot Soc MOP lyengar Commemoration Volume: 101–119
Pechenitsyn VP (1972a) The development of theFritillaria type embryo sac in some Central Asiatic species ofTulipa. Bot Zh 57: 221–229 (in Russian, with English summary)
— (1972b) The double fertilization in species ofTulipa withFritillaria type embryo sac. Bot Zh 57: 465–469 (in Russian, with English summary)
Romanov ID (1936) Die Embryosackentwicklung in der GattungGagea Salisb. Planta 25: 438–459
— (1961) The origin of the unique structure of endosperm nuclei inGagea. Dokl Akad Nauk SSSR 141: 984–986 (in Russian)
— (1962) The origin of the unique structure of endosperm nuclei inGagea. Dokl Bot Sci Sect 141: 188–190
Rutishauser A (1969) Embryologie und Fortpflanzungsbiologie der Angiospermen. Springer, Wien New York
Schnarf K (1941) Vergleichende Cytologie des Geschlechtsapparates der Kormophyten. Borntraeger, Berlin
Stenar H (1927) Über die Entwicklung des siebenkernigen Embryosackes beiGagea lutea Ker., nebst einigen Bemerkungen über die Reduktionsteilung beiGagea minima Ker. Svensk Bot Tidskr 21: 344–360
Tamura MN (1998) Liliaceae. In: Kubitzki K (ed) Flowering plants: monocotyledons — Lilianae (except Orchidaceae). Springer, Berlin Heidelberg New York Tokyo, pp 343–353 (Kubitzki K [ed] The families and genera of vascular plants, vol 3)
Temsch EM, Greilhuber J, Krisai R (1998) Genome size inSphagnum (peat moss). Bot Acta 111: 325–330
Tschermak-Woess E (1963) Strukturtypen der Ruhekerne von Pflanzen und Tieren. Springer, Wien (Alfert M et al [eds] Protoplasmatologia, vol V, 1)
van Went JL, Willemse MTM (1984) Fertilization. In: Johri BM (ed) Embryology of angiosperms. Springer, Berlin Heidelberg New York Tokyo, pp 273–317
Woodard JW (1956) DNA in gametogenesis and embryogeny inTradescantia. J Biophys Biochem Cytol 2: 765–775
Zhang H-Q, Bohdanowicz J, Pierson ES, Li Y-Q, Tiezzi A, Cresti M (1995) Microtubular organization during asymmetrical division of the generative cell inGagea lutea. J Plant Res 108: 269–276
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Dedicated to Professor Walter Gustav Url on the occasion of his 70th birthday
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Greilhuber, J., Ebert, I., Lorenz, A. et al. Origin of facultative heterochromatin in the endosperm ofGagea lutea (Liliaceae). Protoplasma 212, 217–226 (2000). https://doi.org/10.1007/BF01282922
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DOI: https://doi.org/10.1007/BF01282922