Ultrastructural and cytochemical aspects of female gametophyte development in Sedum hispanicum L. (Crassulaceae)

Emilia Brzezicka , Małgorzata Kozieradzka-Kiszkurno

Abstract

Until now, development of the female gametophyte has been investigated only in some species of Crassulaceae using a light microscope. To the best of our knowledge, this is the first report that describes the process of megasporogenesis and megagametogenesis in Crassulaceae in detail. To achieve this, we performed embryological studies on Sedum hispanicum L. (Crassulaceae). Cytochemical analysis detected the presence of proteins, lipids, and insoluble polysaccharides in individual cells of the gametophyte. The development of the embryo sac conforms to the monosporic or Polygonum-type in anatropous, crassinucellate, and bitegmic ovules. One megaspore mother cell initiates the process of megasporogenesis. Prior to the first meiotic division, the nucleus is centrally located within the meiocyte. Other organelles seem to be distributed evenly over the micropylar and chalazal parts during the development. Most storage reserves detected during megasporogenesis were observed in the megaspore mother cell. Three mitotic divisions within the chalazal functional megaspore resulted in the enlargement of the eight-nucleated embryo sac. In the seven-celled gametophyte, three chalazally located antipodes degenerated. A mature embryo sac was formed by the egg apparatus and central cell. When the antipodes degenerated, both synergids became organelle-rich and more active. The concentration of lipid droplets, starch grains, and proteins increased during megagametogenesis in the growing gametophyte. In the cellular embryo sac, the central cell can be distinguished by its largest accumulation. Our data confirm the hypothesis that plasmodesmata with electron-dense dome are formed during development of the female gametophyte in S. hispanicum and not just during the stages of embryogenesis. We observed these structures in megaspores and coenocytic embryo sac walls. Functions of observed plasmodesmata are discussed.
Author Emilia Brzezicka KCiER
Emilia Brzezicka ,,
- Department of Plant Cytology and Embryology
, Małgorzata Kozieradzka-Kiszkurno KCiER
Małgorzata Kozieradzka-Kiszkurno,,
- Department of Plant Cytology and Embryology
Journal seriesProtoplasma, ISSN 0033-183X
Issue year2018
Vol255
No1
Pages247-261
Publication size in sheets0.7
Keywords in Englishembryo sac, megagametogenesis, megasporogenesis, plasmodesmata, polygonum type, ultrastructure
DOIDOI:10.1007/s00709-017-1155-3
URL https://link.springer.com/content/pdf/10.1007%2Fs00709-017-1155-3.pdf
Languageen angielski
LicenseJournal (articles only); author's final; Uznanie Autorstwa (CC-BY); with publication
Score (nominal)30
ScoreMinisterial score = 30.0, 20-12-2017, ArticleFromJournal
Ministerial score (2013-2016) = 30.0, 20-12-2017, ArticleFromJournal
Publication indicators WoS Impact Factor: 2016 = 2.87 (2) - 2016=2.658 (5)
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* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.
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