title: Are obligatory apomicts invested in the pollen tube transmitting tissue? Comparison of the micropyle ultrastructure between sexual and apomictic dandelions (Asteraceae, Lactuceae).
abstract: With the exception of the sunflower, little information concerning the micropyle ultrastructure of the family Asteraceae is available. The aim of our study was to compare the micropyle structure in amphimictic and apomictic dandelions. Ultrastructural studies using buds and flowers during anthesis have been done on the micropyle of the sexual and apomictic Taraxacum. In all of the species that were examined, the micropylar canal was completely filled with ovule transmitting tissue and the matrix that was produced by these cells. The ovule transmitting tissue was connected to the ovarian transmitting tissue. The micropyle was asymmetrical because the integument epidermis that forms the transmitting tissue was only on the funicular side. There was a cuticle between the obturator cells and epidermal cells on the other side of integument. The micropylar transmitting tissue cells and theirs matrix reached the synergid apex. The cytoplasm of the transmitting tissue cells was especially rich in rough endoplasmic reticulum (ER), dictyosomes, and mitochondria. No major differences were detected between the micropyle structure of the amphimictic and apomictic species; thus, a structural reduction of obturator does not exist. The ovule transmitting tissue is still active in apomictic dandelions despite the presence of the embryo and endosperm. Differences and similarities between the micropyle structure in the Asteraceae that have been studied to date are discussed.
authors: Department of Plant Cytology and Embryology, Jagiellonian University in Kraków, Kraków, 9 Gronostajowa St., 30-387, Kraków, Poland, bartosz.plachno@uj.edu.pl.
authors: Bartosz J
authors: BJ
authors: Płachno
authors: Piotr
authors: P
authors: Świątek
authors: Małgorzata
authors: M
authors: Kozieradzka-Kiszkurno
authors: Ľuboš
authors: Ľ
authors: Majeský
authors: Jolanta
authors: J
authors: Marciniuk
authors: Piotr
authors: P
authors: Stolarczyk
mesh_terms: D056625:Endosperm / Q000648:ultrastructure; D019441:Plant Epidermis / Q000648:ultrastructure; D053205:Pollen Tube / Q000648:ultrastructure*; D031205:Taraxacum / Q000648:ultrastructure*
references: Ann Bot. 2005 Oct;96(5):779-91
references: 16046459
references: Protoplasma. 2011 Apr;248(2):391-404
references: 20689973
references: Heredity (Edinb). 1999 Dec;83 ( Pt 6):715-21
references: 10651916
references: Plant Physiol. 2013 Sep;163(1):216-31
references: 23864557
references: Plant J. 2000 Apr;22(2):165-76
references: 10792832
references: Biocell. 2010 Dec;34(3):133-8
references: 21443143
references: Protoplasma. 2013 Jun;250(3):715-22
references: 23001751
references: Protoplasma. 2009 Jul;236(1-4):39-48
references: 19437102
references: J Exp Bot. 2012 May;63(8):3229-41
references: 22378948
references: Protoplasma. 2014 Jan;251(1):211-7
references: 23974526
references: Plant Mol Biol. 2003 Jan;51(2):183-9
references: 12602877
references: PLoS One. 2012;7(8):e41868
references: 22870257
references: Heredity (Edinb). 2003 Apr;90(4):326-35
references: 12692586
references: Plant Cell. 2000 Sep;12(9):1737-50
references: 11006344
references: Am J Bot. 2009 Jan;96(1):183-206
references: 21628183
references: Evolution. 1995 Dec;49(6):1108-1118
references: 28568531
references: Philos Trans R Soc Lond B Biol Sci. 2003 Jun 29;358(1434):1113-21
references: 12831477
references: Plant Reprod. 2013 Jun;26(2):113-23
references: 23471494
references: Bot J Linn Soc. 1989 Apr;99(4):365-376
references: 32327810
references: Mol Ecol. 2000 Jan;9(1):1-8
references: 10652071
references: Sex Plant Reprod. 2010 Mar;23(1):73-86
references: 20165965
references: Mol Ecol. 2013 Dec;22(23):5908-21
references: 24118210