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Female germ unit in Genlisea and Utricularia, with remarks about the evolution of the extra-ovular female gametophyte in members of Lentibulariaceae.

Płachno BJ - Protoplasma (2010)

Bottom Line: The present studies clearly show that synergids in both genera possess a filiform apparatus; however, it seems that Utricularia quelchii synergids have a simpler structure compared to Genlisea aurea and other typical angiosperms.This ancestral characteristic still occurs in some species from the Bivalvaria subgenus.An embryo sac, which grows out beyond the limit of the integument and has contact with nutritive tissue, appeared independently in different Utricularia lineages and as a consequence of this, the egg apparatus changes position from apical to lateral.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Cytology and Embryology, Jagiellonian University, 52 Grodzka st., 31-044, Cracow, Poland. bartek78pl@poczta.onet.pl

ABSTRACT
Lentibulariaceae is the largest family among carnivorous plants which displays not only an unusual morphology and anatomy but also the special evolution of its embryological characteristics. It has previously been reported by authors that Utricularia species lack a filiform apparatus in the synergids. The main purposes of this study were to determine whether a filiform apparatus occurs in the synergids of Utricularia and its sister genus Genlisea, and to compare the female germ unit in these genera. The present studies clearly show that synergids in both genera possess a filiform apparatus; however, it seems that Utricularia quelchii synergids have a simpler structure compared to Genlisea aurea and other typical angiosperms. The synergids are located at the terminal position in the embryo sacs of Pinguicula, Genlisea and were probably also located in that position in common Utricularia ancestor. This ancestral characteristic still occurs in some species from the Bivalvaria subgenus. An embryo sac, which grows out beyond the limit of the integument and has contact with nutritive tissue, appeared independently in different Utricularia lineages and as a consequence of this, the egg apparatus changes position from apical to lateral.

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Ultrastructure of a G. aurea egg cell and central cell. a Micropylar part of egg cell, Egn egg nucleus, m mitochondrion, d dictyosome, P plastid, bar = 0.9 μm; b the part of egg cytoplasm with mitochondria and microtubules (red arrows), bar = 0.3 μm; c the part of the central cell with polar nuclei (Pn), eg egg cell, bar = 1,4 μm; d the part of central cell cytoplasm with active dictyosomes (d), v vacuole, bar = 0,7 μm
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Fig3: Ultrastructure of a G. aurea egg cell and central cell. a Micropylar part of egg cell, Egn egg nucleus, m mitochondrion, d dictyosome, P plastid, bar = 0.9 μm; b the part of egg cytoplasm with mitochondria and microtubules (red arrows), bar = 0.3 μm; c the part of the central cell with polar nuclei (Pn), eg egg cell, bar = 1,4 μm; d the part of central cell cytoplasm with active dictyosomes (d), v vacuole, bar = 0,7 μm

Mentions: For electron microscopy, placentas with ovules were isolated from ovaries and fixed in 2.5% formaldehyde and 2.5% glutaraldehyde in a 0.05 M cacodylate buffer (pH 7.0) for 2 days. The material was postfixed in 1% OsO4 in a cacodylate buffer for 24 h at ∼4°C, rinsed in the same buffer, treated with 1% uranyl acetate in distilled water for 1 h, dehydrated with acetone and embedded in Epon 812 (Fullam, Latham, NY). Semithin sections were stained with methylene blue and examined using an Olympus BX60 microscope. The periodic acid-Schiff (PAS) reaction (Wędzony 1996) was used to detect water insoluble polysaccharides with 1,2-glycol groups. Ultrathin sections were cut on a Leica ultracut UCT ultramicrotome. After contrasting with uranyl acetate and lead citrate, the sections were examined using a Hitachi H500 electron microscope.


Female germ unit in Genlisea and Utricularia, with remarks about the evolution of the extra-ovular female gametophyte in members of Lentibulariaceae.

Płachno BJ - Protoplasma (2010)

Ultrastructure of a G. aurea egg cell and central cell. a Micropylar part of egg cell, Egn egg nucleus, m mitochondrion, d dictyosome, P plastid, bar = 0.9 μm; b the part of egg cytoplasm with mitochondria and microtubules (red arrows), bar = 0.3 μm; c the part of the central cell with polar nuclei (Pn), eg egg cell, bar = 1,4 μm; d the part of central cell cytoplasm with active dictyosomes (d), v vacuole, bar = 0,7 μm
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3066386&req=5

Fig3: Ultrastructure of a G. aurea egg cell and central cell. a Micropylar part of egg cell, Egn egg nucleus, m mitochondrion, d dictyosome, P plastid, bar = 0.9 μm; b the part of egg cytoplasm with mitochondria and microtubules (red arrows), bar = 0.3 μm; c the part of the central cell with polar nuclei (Pn), eg egg cell, bar = 1,4 μm; d the part of central cell cytoplasm with active dictyosomes (d), v vacuole, bar = 0,7 μm
Mentions: For electron microscopy, placentas with ovules were isolated from ovaries and fixed in 2.5% formaldehyde and 2.5% glutaraldehyde in a 0.05 M cacodylate buffer (pH 7.0) for 2 days. The material was postfixed in 1% OsO4 in a cacodylate buffer for 24 h at ∼4°C, rinsed in the same buffer, treated with 1% uranyl acetate in distilled water for 1 h, dehydrated with acetone and embedded in Epon 812 (Fullam, Latham, NY). Semithin sections were stained with methylene blue and examined using an Olympus BX60 microscope. The periodic acid-Schiff (PAS) reaction (Wędzony 1996) was used to detect water insoluble polysaccharides with 1,2-glycol groups. Ultrathin sections were cut on a Leica ultracut UCT ultramicrotome. After contrasting with uranyl acetate and lead citrate, the sections were examined using a Hitachi H500 electron microscope.

Bottom Line: The present studies clearly show that synergids in both genera possess a filiform apparatus; however, it seems that Utricularia quelchii synergids have a simpler structure compared to Genlisea aurea and other typical angiosperms.This ancestral characteristic still occurs in some species from the Bivalvaria subgenus.An embryo sac, which grows out beyond the limit of the integument and has contact with nutritive tissue, appeared independently in different Utricularia lineages and as a consequence of this, the egg apparatus changes position from apical to lateral.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Cytology and Embryology, Jagiellonian University, 52 Grodzka st., 31-044, Cracow, Poland. bartek78pl@poczta.onet.pl

ABSTRACT
Lentibulariaceae is the largest family among carnivorous plants which displays not only an unusual morphology and anatomy but also the special evolution of its embryological characteristics. It has previously been reported by authors that Utricularia species lack a filiform apparatus in the synergids. The main purposes of this study were to determine whether a filiform apparatus occurs in the synergids of Utricularia and its sister genus Genlisea, and to compare the female germ unit in these genera. The present studies clearly show that synergids in both genera possess a filiform apparatus; however, it seems that Utricularia quelchii synergids have a simpler structure compared to Genlisea aurea and other typical angiosperms. The synergids are located at the terminal position in the embryo sacs of Pinguicula, Genlisea and were probably also located in that position in common Utricularia ancestor. This ancestral characteristic still occurs in some species from the Bivalvaria subgenus. An embryo sac, which grows out beyond the limit of the integument and has contact with nutritive tissue, appeared independently in different Utricularia lineages and as a consequence of this, the egg apparatus changes position from apical to lateral.

Show MeSH
Related in: MedlinePlus