Comparative pollen morphology and taxonomic ... - CNCFlora
Comparative pollen morphology and taxonomic ... - CNCFlora
Comparative pollen morphology and taxonomic ... - CNCFlora
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92 R.L.B. de Borges et al. / Review of Palaeobotany <strong>and</strong> Palynology 154 (2009) 91–105<br />
Table 1<br />
Previous morphological <strong>pollen</strong> data of representatives of the Eriocaulaceae family<br />
Authors Taxa Method Subject<br />
Erdtman (1943) Eriocaulon septangulare Withering LM Pollen <strong>morphology</strong> <strong>and</strong> plant taxonomy - Angiosperms<br />
Kuprianova (1948) Eriocaulon benthamii Kunth <strong>and</strong> Paepalanthus blepharocnemis Mart. LM Pollen <strong>morphology</strong> of monocotyledons<br />
Erdtman (1952) Syngonanthus wahlbergii (Wikstr.) Ruhl <strong>and</strong> Tonina fluviatilis Aubl. LM Pollen <strong>morphology</strong> <strong>and</strong> plant taxonomy - Angiosperms<br />
Ikuse (1956) Eriocaulon miquelianum Körn., E. nipponicum Maxim., E. parvum Körn,<br />
E. senile Honda, <strong>and</strong> E. sielboldianum Sieb. et Zucc. (= E. cinereum R. Br.)<br />
LM Pollen flora of Japan<br />
Thanikaimoni (1965) Eriocaulon L. (46 spp.), Lachnocaulon Kunth (2 spp.),<br />
Leiothrix Ruhl<strong>and</strong> (1 sp.), Paepalanthus Mart. (1 sp.),<br />
Philodice Mart. (1 sp.), Syngonanthus Ruhl<strong>and</strong> (2 spp.),<br />
<strong>and</strong> Tonina Aubl. (1 sp.)<br />
LM Pollen <strong>morphology</strong> of the Eriocaulaceae family<br />
Huang (1972) Eriocaulon cinerum R. Br. Var. sieboldianum (Sieb. & Zucc.) T. Kayama,<br />
E. merrillii Ruhl., E. nantoense Hay., E. trisectum Satake,<br />
E. truncatum Buch.-Ham.<br />
LM Pollen flora of Taiwan<br />
Ybert (1979) Mesanthemum prescottianum (Bong.) Körn. LM Pollen flora of the Ivory Coast<br />
Furness (1988) Eriocaulon aquaticum (Hill) Druce. LM, SEM Eriocaulaceae in the Northwest European <strong>pollen</strong> flora<br />
Santos et al. (2000) Actinocephalus (8 spp.) <strong>and</strong> Paepalanthus (7 spp.) LM Pollen <strong>morphology</strong> of some Brazilian Eriocaulaceae<br />
Rull (2003) Paepalanthus perplexans Mold. LM Illustrated <strong>pollen</strong> key of some Venezuelan species<br />
Coan et al. (2007a) Syngonanthus caulescens (Poir.) Ruhl<strong>and</strong> SEM Embryological study of the species, only SEM pictures<br />
of <strong>pollen</strong> grains were presented<br />
Coan et al. (2007b) Leiothrix fluitans (Mart.) Ruhl<strong>and</strong> SEM Embryological study of the species, only SEM pictures<br />
of <strong>pollen</strong> grains were presented<br />
Method: LM — light microscopy, SEM — scanning electron microscopy.<br />
The first study of the Eriocaulaceae using scanning electron<br />
microscopy was undertaken by Furness (1988), who described the<br />
<strong>pollen</strong> grains of Eriocaulon aquaticum (Hill) Druce. Coan et al. (2007a,b)<br />
published electro-micrographs of the <strong>pollen</strong> grains of Syngonanthus<br />
caulescens (Poir.) Ruhl<strong>and</strong> <strong>and</strong> Leiothrix fluitans (Mart.) Ruhl<strong>and</strong> as a<br />
part of their study of the embryology of these taxa.<br />
Considering all the <strong>pollen</strong> morphological data related to the<br />
Eriocaulaceae to date, only 87 taxa have been described, of which 60 are<br />
species belonging to the genus Eriocaulon. Furthermore, the principal<br />
<strong>pollen</strong> study of the family (Thanikaimoni, 1965) was published 43 years<br />
ago <strong>and</strong> employed only light microscopy. For these reasons, the objective<br />
of the present work was to provide a more complete study of the family<br />
<strong>and</strong> to clarify the patterns of the <strong>pollen</strong> apertures exhibited by the different<br />
<strong>taxonomic</strong> groups, using both light <strong>and</strong> scanning electron microscopy.<br />
2. Materials <strong>and</strong> methods<br />
In accordance with Ruhl<strong>and</strong>'s (1903) classification system for<br />
Eriocaulaceae, we studied the <strong>pollen</strong> grains of 55 species from the<br />
genera Actinocephalus, Blastocaulon, Eriocaulon, Lachnocaulon, Leiothrix,<br />
Paepalanthus, Philodice, Rondonanthus, Syngonanthus, <strong>and</strong>Tonina. The<br />
genus Mesanthemum was not included in this work due to the lack of<br />
study material, but both of the subfamilies cited by Ruhl<strong>and</strong> (1903),<br />
Eriocauloideae <strong>and</strong> Paepalanthoideae, were considered. Taxonomic<br />
arrangement of the group is:<br />
Order Poales<br />
Fam. Eriocaulaceae<br />
Subfam. Eriocauloideae<br />
Eriocaulon 400/4 1<br />
Mesanthemum 12/0<br />
Paepalanthoideae<br />
Actinocephalus 29/6<br />
Blastocaulon 5/2<br />
Lachnocaulon 7/2<br />
Leiothrix 37/9<br />
Paepalanthus 485/15<br />
Philodice 2/1<br />
Rondonanthus 6/1<br />
Syngonanthus 200/14<br />
Tonina 1/1<br />
1 Total number of species/number of species included in present study.<br />
Pollen samples (the capitula) for our analyses were obtained from<br />
herbarium specimens that had been securely identified <strong>and</strong> incorporated<br />
into the Herbário da Universidade Estadual de Feira de Santana —<br />
HUEFS, Herbarium of the Miami University — MU, <strong>and</strong> Herbário do<br />
Departamento de Botânica, Instituto de Biociências (Universidad de São<br />
Paulo) — SPF. All of the specimens examined are listed in the Appendix A.<br />
The acetolysis method (Erdtman, 1960) was used for the light<br />
microscope (LM) analysis of the <strong>pollen</strong> grains of 36 species. For each<br />
species, at least 20 <strong>pollen</strong> grains were used (except when not possible)<br />
in the morphometric analyses of the principal <strong>pollen</strong> parameters:<br />
diameter, width of the interapertural exine strip, thickness of the<br />
exine layers, <strong>and</strong> length of the spines.<br />
For the scanning electron microscopy (SEM) studies, 41 species of the<br />
above-mentioned genera were examined. Due to the fragile nature of<br />
the <strong>pollen</strong> grains <strong>and</strong> their low production, the anthers were removed<br />
from the flowers <strong>and</strong> opened directly over a stub covered by doublefaced<br />
self-adhesive carbon tape. The material was subsequently coated<br />
with gold <strong>and</strong> analyzed (LEO 1430 VP — Carl Zeiss).<br />
Photographs of the <strong>pollen</strong> characteristics were obtained under<br />
both LM <strong>and</strong> SEM techniques. The palynological nomenclature used<br />
follows Punt et al. (2007), <strong>and</strong> that of the type of aperture follows<br />
Pozhidaev (2000).<br />
All of the prepared material is deposited in the palynotheca of the<br />
Laboratory of Plant Micro<strong>morphology</strong> (LAMIV) at the Universidade<br />
Estadual de Feira de Santana, Bahia State, Brazil.<br />
3. Results<br />
3.1. General <strong>pollen</strong> <strong>morphology</strong><br />
All species of Eriocaulaceae studied here had <strong>pollen</strong> grains that<br />
were monads, generally spherical, <strong>and</strong> varied in size from small (up to<br />
25 µm) to medium (N25 µm) (Table 2). The smallest <strong>pollen</strong> grains are<br />
observed in Blastocaulon albidum, Lachnocaulon minus, Paepalanthus<br />
tortilis, <strong>and</strong> P. subtilis, while the largest grains are seen in Paepalanthus<br />
comans, P. planifolius (both P. subg. Platycaulon) <strong>and</strong> Rondonanthus<br />
duidae. Variations among the sizes of the <strong>pollen</strong> grains of the same<br />
specimen are relatively large: up to 14 µm as recorded for Syngonanthus<br />
schwackei (T. B. Cavalcanti et al. 2906) <strong>and</strong> 15 µm for Paepalanthus<br />
pulvinatus (M. J. G. Andrade 106). This fact may be due to<br />
rupturing of the aperture during chemical treatment (acetolysis),<br />
which increases the size of the <strong>pollen</strong> grains.<br />
Constant features among the <strong>pollen</strong> grains of the species of<br />
Eriocaulaceae that were analyzed are the spiral apertures <strong>and</strong> that the