Acta Botanica Brasilica 28(3): 352-360. 2014.
doi: 10.1590/0102-33062014abb3482
Pollen morphology of selected species of the subfamily
Bombacoideae (Malvaceae sensu lato)1
Vanessa Holanda Righetti de Abreu2, Claudia Barbieri Ferreira Mendonça2 and Vania Gonçalves-Esteves2,3
Received: 21 December, 2013. Accepted: 28 January, 2014
ABSTRACT
We analyzed the pollen grains of 11 species within the subfamily Bombacoideae. The pollen grains were acetolyzed,
after which they were analyzed and photographed under light microscopy. Unacetolyzed pollen grains were analyzed
and photomicrographed under scanning electron microscopy. We studied pollen characters such as shape, size,
exine ornamentation and aperture type. The species were separated by a pollen key, which considers the presence or
absence of “calotte” in the pollen grains. This attribute separated Ceiba and Eriotheca from the other genera. Some
species are differentiated by specific characters: in Bombacopsis glabra and B. stenopetala, the sexine is rugulate or
“vermiculate” with isolated pilate elements; in B. calophylla, the pollen grains are sinu-aperturate; Ceiba speciosa show
atypical, duplicolumellate sexine; C. erianthos is the only species with 5-colporate pollen grains and a pentagonal amb;
in Pachira aquatica the reticulum has muri with spiculaspinulose muri (“reticulum cristate”). The variation in the
pollen morphology confirms the eurypalynous status of the genera studied here.
Key words: Atlantic Forest, Bombacoideae, palynology, Rio de Janeiro
Introduction
The order Malvales comprises approximately 10 families, 338 genera and 6005 species, with distribution primarily in tropical regions (APG II 2003).
Phylogenetic studies on Malvaceae sensu lato (Bayer et
al. 1999) have identified nine clades, corresponding to the
following subfamilies: Bombacoideae, Brownlowioideae,
Byttnerioideae, Dombeyoideae, Grewioideae, Helicteroideae, Malvoideae, Sterculioideae, and Tilioideae. The
subfamily Bombacoideae is pantropical and is generally
represented by large, unbranched or aculeate trees, some
with ventricose trunks in the middle portion, due to storage
of water in the parenchyma (Duarte 2006).
The importance of palynology in the taxonomic classification of families and subfamilies has been demonstrated in
various studies that used pollen data to reassess the groups;
the study conducted by Saba (2007) is the one that best covers the species of Brazil, in terms of numbers and details.
Similar studies include those conducted by Robyns (1963),
Tsukada (1964), Palacios-Chávez (1966), Robyns (1971),
Robyns & Nilsson (1975, 1981), Nilsson & Robyns (1974,
1986), Perveen et al. (2004), and Perveen & Qaiser (2007).
Due to the taxonomic importance of the Malvaceae
family and the need for studies to corroborate the circum-
scription of the group, which remains uncertain, this study
aimed to characterize the pollen morphology of the Bombacoideae species occurring in the state of Rio de Janeiro,
which are distributed predominantly in areas of restinga
(coastal woodland) and Atlantic Forest, in order to support
taxonomic studies of the group.
Material and methods
The botanical material was taken from specimens
deposited in herbaria: GUA, HB, R, RB and RBR; which
acronyms are in accordance with the Index Herbariorum
(Thiers continuously updated).
We collected buds or flowers from 11 species of the subfamily Bombacoideae: Bombacopsis calophylla (K. Schum.)
A. Robyns; B. glabra (Pasq.) Robyns; B. stenopetala A. Robyns; Ceiba crispiflora (Kunth) Ravenna; C. erianthos (Cav.)
K. Schum.; C. speciosa A. St.-Hil.; Eriotheca pentaphylla
(Vell.) A. Robyns; Pachira aquatica Aubl.; Pseudobombax
grandiflorum (Cav.) A. Robyns; Pseudobombax marginatum
(A. St.-Hil., Juss. & Cambess.) A. Robyns; and Spirotheca
rivieri (Decne.) Ulbr. The slides used in the study were deposited in the Palynology Collection of the Álvaro Xavier
Moreira Laboratory of Palynology, in the Botany Depart-
Based on the Master’s dissertation of the first author
Universidade Federal do Rio de Janeiro, Museu Nacional, Departamento de Botânica, Laboratório de Palinologia, Rio de Janeiro, RJ, Brasil
3
Author for correspondence: esteves.vr@gmail.com
1
2
Pollen morphology of selected species of the subfamily Bombacoideae (Malvaceae sensu lato)
ment of the National Museum of the Federal University of
Rio de Janeiro.
The pollen samples to be analyzed under light microscopy were treated with acetolysis (Erdtman 1960), as
modified by Melhem et al. (2003), and measured within
seven days of preparation (Salgado-Labouriau 1973). The
images were captured with a Zeiss Axiostar Plus microscope
(Carl Zeiss, Oberkochen, Germany). Pollen grains of each
species (n = 25) were measured in equatorial view (polar
diameter and equatorial diameter). The means, standard
deviations of the mean, and 95% confidence intervals were
calculated. Ten similar measurements of pollen grains were
obtained from additional material—from another collection
(hereafter referred to as comparison material)—to verify the
stability of the data obtained from the reference material
(Aguiar et al. 2008; Abreu et al. 2012; Moreira et al. 2013).
Pollen grains (n = 10/species) were also measured in polar
view (equatorial diameter in polar view and apocolpium
side). Exine thickness and apertures (n = 10/species) were
measured, and the arithmetic means were calculated. In
describing the pollen characters, we used the terminology
established by Punt et al. (2007), except for the polar area
index and the size of the apertures, for which we used the
classification system established by Faegri & Iversen (1966).
Unacetolyzed pollen grains were mounted on stubs with
double-sided carbon tape and sputter-coated (for 3 min)
with a thin layer of palladium-gold. The photomicrographs
were taken under scanning electron microscopy with either
a JSM-5310 microscope (JEOL, Ltd., Tokyo, Japan), in the
Hertha Meyer Laboratory of Cellular Ultrastructure at the
Federal University of Rio de Janeiro Institute of Biophysics,
or a JSM-6390LV (JEOL, Ltd.) at the Electron Microscopy
Center of the Department of Invertebrates of the National
Museum of the Federal University of Rio de Janeiro.
Results
1. Bombacopsis calophylla (Fig. 1A-D), B. glabra (Fig. 1E-H),
and B. stenopetala (Fig. 1I-L):
Pollen grains large, isopolar, peroblate (B. calophylla),
oblate (B. glabra) and suboblate (B. stenopetala); with
small or large polar area (Tab. 1 and 2), triangular amb,
sinu-aperturate (B. calophylla only) or planaperturate,
3-colporate, long or short colpi in B. stenopetala, narrow
colpi with prominent and ornamented margin, lolongate
endoaperture (Tab. 3), wide mesocolpium, with large and
“calotte”-shaped vertices with truncated contours only in
B. calophylla (Fig. 1A and 1B) or smaller and rounded in
the two other species (Fig. 1E, 1F, and 1I); in B. calophylla,
the sexine is rugulate in the apocolpium (Fig. 1B, D) and
microreticulate to rugulate near the apertures (Fig. 1C),
muri with sparse perforations in the mesocolpium (Fig. 1B);
in B. glabra and B. stenopetala, the sexine is “vermiculate”
with isolated pilate elements, scabrate on the “calotte” (Fig.
1E, 1G, I), the distribution of the ornamentation elements
being densest in B. stenopetala; sexine thicker than nexine.
The pollen grain falls preferably in polar view, making it
difficult to establish the shape and to measure the aperture.
2. Ceiba crispiflora (Fig. 2A-D), C. erianthos (Fig. 2E-H),
and C. speciosa (Fig. 2I-L)
Pollen grains large, isopolar, suboblate, with a polar area
that is small in C. erianthos, large in C. crispiflora, and large
to very large in C. speciosa; subcircular or pentagonal amb
in C. erianthos, 3-colporate with small colpi in C. crispiflora
(Fig. 2C), 3(-4)-colporate with colpi ranging from short to
very small in C. speciosa, (Fig. 2I and 2J), 5-colporate with
long colpi in C. erianthos (Fig. 2G); narrow colpi with ornamented margin, not prominent, lolongate endoaperture
Table 1. Measurements of pollen grains of species within the subfamily Bombacoideae occurring in areas of restinga (coastal woodland) and Atlantic Forest in the
state of Rio de Janeiro (n = 25 grains/species, in equatorial view).
Polar diameter
Species
Equatorial diameter
(μm)
Variation
±s
(μm)
95% CI
Variation
±s
PD/ED
Shape
95% CI
Bombacopsis calophylla
25.0-26.0
25.5±0.1
25.3-25.7
70.0-72.0
71.0±0.2
70.6-71.4
0.36
peroblate
B. glabra
47.5-57.5
53.0±0.5
52.0-54.0
62.5-77.5
71.2±0.9
69.4-73.0
0.74
oblate
B. stenopetala
55.0-57.5
55.6±0.2
55.2-56.0
67.5-77.5
71.0±0.8
69.4-72.6
0.78
suboblate
Ceiba crispiflora
53.0-63.0
58.1±0.6
56.9-59.3
56.0-72.0
66.9±0.9
65.1-68.7
0.87
suboblate
C. erianthos
40.0-52.5
50.2±0.8
48.6-51.8
57.5-72.5
66.4±0.9
64.6-68.2
0.76
suboblate
C. speciosa
45.0-57.5
51.4±0.6
50.2-52.6
60.0-67.5
64.0±0.7
62.6-65.4
0.80
suboblate
Eriotheca pentaphylla
35.0-38.0
35.8±0.3
35.2-36.4
51.0-52.0
51.3±0.1
51.1-51.2
0.69
oblate
Pachira aquatica
37.5-47.5
42.7±0.6
41.5-43.9
70.0-77.5
72.1±0.4
71.3-72.9
0.59
oblate
Pseudobombax grandiflorum
42.5-45.0
44.5±0.2
44.1-44.9
82.5-95.0
88.2±0.8
86.6-89.8
0.50
oblate
Pseudobombax marginatum
55.0-62.5
58.8±0.8
57.2-60.4
77.5-92.5
85.0±1.5
81.9-88.1
0.70
oblate
Spirotheca rivieri
36.0-43.0
40.3±0.4
39.5-41.1
55.0-65.0
60.6±0.5
59.6-61.6
0.66
oblate
±s – arithmetic mean±standard deviation; 95% CI – 95% confidence interval; PD/ED – polar:equatorial diameter ratio.
Acta bot. bras. 28(3): 352-360. 2014.
353
Vanessa Holanda Righetti de Abreu, Claudia Barbieri Ferreira Mendonça and Vania Gonçalves-Esteves
Table 2. Measurements of pollen grains of species within the subfamily Bombacoideae occurring in areas of restinga (coastal woodland) and Atlantic Forest in the
state of Rio de Janeiro (n = 10 grains/species, in polar view).
EDPV
Species
AS
(μm)
(μm)
PAI
Polar area size
0.43
small
Range
Range
Bombacopsis calophylla
60.0-72.5
65.5
25.0-32.5
28.1
B. glabra
62.5-72.5
66.1
22.5-35.0
28.3
0.43
small
B. stenopetala
62.5-72.5
65.3
27.5-40.0
34.5
0.53
large
Ceiba crispiflora
52.0-66.0
58.4
27.0-34.0
30.2
0.52
large
C. erianthos
55.0-77.5
65.3
20.0-30.0
23.8
0.36
small
C. speciosa
57.5-67.5
63.7
50.0-60.0
54.5
0.85
very large
Eriotheca pentaphylla
47.5-55.0
50.5
30.0-35.0
31.7
0.62
large
Pachira aquatica
65.0-75.0
70.9
37.5-47.5
42.5
0.60
large
Pseudobombax grandiflorum
76.3-90.0
84.1
32.5-52.5
43.3
0.51
large
Pseudobombax marginatum
70.0-85.0
80.2
27.5-37.5
33.2
0.41
small
Spirotheca rivieri
50.0-62.5
56.3
22.5-37.5
29.5
0.52
large
EDPV – equatorial diameter in polar view; AS – apocolpium side; – arithmetic mean; 95% CI – 95% confidence interval; PAI – polar area index.
(Tab. 3), reticulate and heterobrochate sexine, high, narrow
and sinuous muri (Fig. 2D, 2H, and 2L): simplicolumellate
with no elevation at the lumina intersection in C. crispiflora
(Fig. 2D), or with elevation at the intersection of lumina, with
perforations in C. erianthos; apparent columellae, sometimes
branched or bifurcate in C. erianthos; large lumina, with ornamentation in C. erianthos (Fig. 2H) or without ornamentation in C. crispiflora (Fig. 2D) and C. speciosa (Fig. 2L). In C.
speciosa, muri are duplicolumellate in some regions, one of
the rows has shorter columellae forming the muri, although
it does not reach the base of the columellae in the other row
(Fig. 2L); sexine thicker than nexine (Tab. 3).
3. Eriotheca pentaphylla (Fig. 2M-O)
Pollen grains large, isopolar, oblate, with large polar
area (Tab. 1 and 2), subtriangular amb, planaperturate,
3-colporate, small and narrow colpi, with no prominent
ornamented margin (Fig. 2N); lalongate endoaperture (Tab.
3), heterobrochate reticulate sexine, low and wide muri,
with sparse perforations, non apparent columellae, without
bifurcation, intensely granulated lumen (Fig. 2O); sexine
thicker than nexine (Tab. 3).
4. Pachira aquatica (Fig. 3A-C)
Pollen grains large, isopolar, oblate, with a large polar
area (Tab. 1 and 2), subtriangular amb, planaperturate,
3-colporate, small and narrow colpi with psilate margin,
lolongate endoaperture (Tab. 3). The mesocolpium is large
and has a large “calotte” with rounded contours, psilate in
the most distal region (Fig. 3A and 3B) with 1-3 rows of
perforations in the region between the border of the “calotte”
and the surface of the pollen grains, in the other surface
regions, the sexine is reticulate, heterobrochate, with low,
narrow spinulose muri (“ reticulum cristatum” according to
354
Hesse et al. 2009), columellae are not apparent and without
bifurcation, lumen without ornamentation (Fig. 3B); sexine
thicker than nexine (Tab. 3).
5. Pseudobombax grandiflorum (Fig. 3A-C) and P. marginatum (Fig. 3D-G)
Pollen grains large, isopolar, oblate, with a polar area that
is small in P. marginatum and large in P. grandiflorum (Tab.
1 and 2), subtriangular amb, planaperturate, 3-colporate,
long and narrow colpi with ornamented margin which is not
prominent in P. marginatum, or small and very wide colpi
with psilate margin in P. grandiflorum (Tab. 3), lolongate
endoaperture (Fig. 3F, Tab. 3); the mesocolpium is wide and
has a small, rounded ”calotte”, psilate surface (Fig. 3D, E), in
other regions of the surface, the sexine is reticulate heterobrochate, with smooth, low, wide, straight muri, with sparse
perforations in P. grandiflorum (Fig. 3G) or many perforations
in P. marginatum (Fig. 3I), with no apparent columellae; they
have minor lumina around major lumina; lumina with ornamentation (Fig. 3D, E, G); sexine thicker than nexine (Tab. 3).
6. Spirotheca rivieri (Fig. 3J-L)
Pollen grains large, isopolar, oblate, with a large polar
area (Tab. 1 and 2), subtriangular amb, planaperturate,
3-colporate, short and narrow colpi with highly ornamented
and prominent margins, lolongate endoaperture (Tab. 3);
the mesocolpium shows a smaller “calotte” with rounded
contours, with a sexine that is psilate only in the most distal
region, becoming microreticulate in the basal part of the
“calotte” (Fig. 3J), in the apocolpium and near the apertures,
the sexine is reticulate and heterobrochate, with high, narrow and straight muri with sparse perforations, apparent
columellae without bifurcation, lumina without ornamentation (Fig. 3K, L); sexine thicker than nexine (Tab. 3).
Acta bot. bras. 28(3): 352-360. 2014.
Pollen morphology of selected species of the subfamily Bombacoideae (Malvaceae sensu lato)
Figure 1. Pollen grains of species within the subfamily Bombacoideae (genus Bombacopsis) occurring in areas of restinga (coastal woodland) and Atlantic Forest
in the state of Rio de Janeiro, under light microscopy (LM) and scanning electron microscopy (SEM): B. calophylla in polar view—A. optical section (LM) and B.
general aspect (SEM); B. calophylla in equatorial view—C. aperture detail (SEM) and D. aperture detail (SEM); B. glabra in polar view—E. optical section (LM), F.
general aspect (SEM), and G. ornamentation detail (SEM); B. glabra in equatorial view—H. aperture (SEM); B. stenopetala in polar view—I. general aspect (SEM);
B. stenopetala in equatorial view—J. general aspect (SEM), K. aperture (LM), and L. ornamentation detail (SEM).
Acta bot. bras. 28(3): 352-360. 2014.
355
Vanessa Holanda Righetti de Abreu, Claudia Barbieri Ferreira Mendonça and Vania Gonçalves-Esteves
Figure 2. Pollen grains of species within the subfamily Bombacoideae (genera Ceiba and Eriotheca) occurring in areas of restinga (coastal woodland) and Atlantic
Forest in the state of Rio de Janeiro, under light microscopy (LM) and scanning electron microscopy (SEM): C. crispiflora in polar view—A. optical section (LM)
and B. general aspect (SEM); C. crispiflora in equatorial view—C. aperture (LM) and D. ornamentation detail (SEM); C. erianthos in polar view—E. optical section
(LM) and F. general aspect (SEM); C. erianthos in equatorial view—G. aperture (SEM) and H. ornamentation detail (SEM); C. speciosa in polar view—I. general
aspect (SEM); C. speciosa in equatorial view—J. aperture (LM), K. aperture (SEM), and L. ornamentation detail (SEM); Eriotheca pentaphylla in polar view—M.
general aspect (SEM); E. pentaphylla in equatorial view—N. aperture (SEM) and O. ornamentation detail (SEM).
Arrow in C indicates endoaperture.
356
Acta bot. bras. 28(3): 352-360. 2014.
Pollen morphology of selected species of the subfamily Bombacoideae (Malvaceae sensu lato)
Table 3. Measurements of apertures and exine layers of pollen grains of species within the subfamily Bombacoideae occurring in areas of restinga (coastal woodland)
and Atlantic Forest in the state of Rio de Janeiro (n = 10 grains/species).
Species
Colpus
Endoaperture
Exine layers
(μm)
(μm)
(μm)
length
width
margin
length
width
exine
sexine
nexine
Bombacopsis calophylla
12.8
2.4
1.2
5.1
3.2
2.3
1.3
1.0
B. glabra
19.5
3.5
3.6
8.6
4.5
4.7
2.8
1.9
B. stenopetala
15.3
2.2
3.5
7.0
2.7
5.3
3.3
2.0
Ceiba crispiflora
14.3
2.3
---
6.9
3.2
4.1
3.1
1.0
C. erianthos
19.0
2.6
---
6.9
3.4
3.1
2.1
1.0
C. speciosa
14.8
2.7
---
6.7
3.8
5.0
3.5
1.5
Eriotheca pentaphylla
10.9
2.2
---
5.2
7.9
3.4
2.4
1.0
Pachira aquatica
14.8
2.8
---
6.9
3.8
2.9
1.9
1.0
Pseudobombax grandiflorum
24.7
8.3
---
9.7
8.3
2.3
1.2
1.1
Pseudobombax marginatum
34.3
2.1
---
11.6
7.0
3.0
2.0
1.0
Spirotheca rivieri
14.6
2.0
---
5.7
3.2
4.1
2.8
1.3
Pollen key for Bombacoideae species
1. Pollen grains without “calotte”
2. 5-colporate pollen grains, pentagonal amb ..................................................................................................Ceiba erianthos
2. 3(-4)-colporate pollen grains, subcircular or subtriangular amb
3. Pollen grains with duplicolumellate sexine with one of the rows showing shorter columellae ........Ceiba speciosa
3. Pollen grains with simplicolumellate sexine
4. Lalongate endoaperture, reticulum with intensely granulate lumina................................ Eriotheca pentaphylla
4. Lolongate endoaperture, reticulum without intensely granulate lumina................................... Ceiba crispiflora
1. Pollen grains with “calotte”
5. Rugulate or “vermiculate” sexine
6. Large “calotte” with truncated contours, rugulate sexine in the apocolpium, sinu-aperturate ....Bombacopsis calophylla
6. Small “calotte” with rounded contours, “vermiculate” sexine, planaperturate ................................Bombacopsis glabra,
............................................................................................................................................................. Bombacopsis stenopetala
5. Reticulate sexine
7. Muri of the reticulum with spinules (“reticulum cristate”) ................................................................Pachira aquatica
7. Muri of the reticulum without spinules
8. Muri of the reticulum are high and narrow, with apparent columellae,
lumina without ornamentation........................................................................................................... Spirotheca rivieri
8. Muri of the reticulum are low, wide, with no apparent columellae, lumina with ornamentation
9. Muri of the reticulum without minor lumina around major lumina ....................Pseudobombax grandiflorum
9. Muri of the reticulum with minor lumina around major lumina ........................... Pseudobombax marginatum
Discussion
Here, we analyzed the pollen grains 11 species within
six genera. Most of those species could be separated on the
basis of characters related to sexine ornamentation and to
the number of apertures (see pollen key). The absence of a
“calotte” separated the genera Ceiba and Eriotheca from the
four other genera evaluated. Some species are differentiated
by particular characters: in Bombacopsis glabra and B. stenopetala, the sexine is rugulate or vermiculate; Ceiba speciosa
has an atypical duplicolumellate sexine (one of the rows has
Acta bot. bras. 28(3): 352-360. 2014.
columellae starting from the tectum and continuing toward
the basal layer); in Pachira aquatica the reticulum has muri
with spinules (“reticulum cristate”).
Robyns (1963), in his monograph on the genus Bombax
sensu lato (Bombacaceae), used palynological attributes associated with the analysis of macromorphological characters
to achieve taxonomic delineation among various species of
the Bombax complex, including Bombacopsis calophylla, B.
glabra, B. stenopetala, Eriotheca pentaphylla, Pachira aquatica, Pseudobombax grandiflorum, and P. marginatum. The
results obtained here, in general, are very similar to those
357
Vanessa Holanda Righetti de Abreu, Claudia Barbieri Ferreira Mendonça and Vania Gonçalves-Esteves
Figure 3. Pollen grains of species within the subfamily Bombacoideae (genera Pachira, Pseudobombax, and Spirotheca) occurring in areas of restinga (coastal woodland) and Atlantic Forest in the state of Rio de Janeiro, under light microscopy (LM) and scanning electron microscopy (SEM): Pachira aquatica in polar view—A.
optical section (LM) and B. general aspect (SEM); Pachira aquatica in equatorial view—C. aperture (LM); Pseudobombax grandiflorum in polar view—D. optical
section (LM) and E. general aspect (SEM); Pseudobombax grandiflorum in equatorial view—F. aperture (LM) and G. ornamentation detail (SEM); Pseudobombax
marginatum in polar view—H. general aspect (SEM) and I. ornamentation detail (SEM); Spirotheca rivieri in polar view—J. general aspect (SEM) and K. ornamentation detail (SEM); S. rivieri in equatorial view—L. aperture detail (SEM).
358
Acta bot. bras. 28(3): 352-360. 2014.
Pollen morphology of selected species of the subfamily Bombacoideae (Malvaceae sensu lato)
obtained by Robyns (1963), who used only light microscopy,
the exception being the description of the type of aperture in
B. glabra, which that author categorized as colpate whereas
we found it to be colporate.
Tsukada (1964) analyzed the pollen grains of 31 taxa
subordinated to various genera, including the species
Ceiba erianthos, Pachira aquatica and Spirotheca rivieri.
In comparing our results with those of that authors, we
identified differences regarding the shape of pollen grains
and the thickness of the exine in Ceiba erianthos and in
Pachira aquatica, as well as regarding the type of aperture
in Ceiba erianthos.
Palacios-Chávez (1966) analyzed the pollen grains of
trees in the state of Morelos, Mexico. Within the family
Bombacaceae (subfamily Bombacoideae), the author examined three species of Ceiba: C. aesculifolia (H.B.K.) Britt.
& Baker; C. parvifolia Rose; C. pentandra (L.) Gaertn.; and
Bombax ellipticum H.B.K. Although those were not the
same species examined here, we compared our results with
those of that author and identified differences. Whereas
Palacios-Chávez (1966) reported that all three species were
tricolporate with a “per-reticulate” sexine, we found that the
Ceiba species evaluated here were (3-4)-5-colporate with a
characteristically reticulate sexine.
In a study of pollen grains of savanna species, SalgadoLabouriau (1973) examined several families, including
Bombacaceae (species currently subordinated to Bombacoideae), creating or accepting pollen types. Within the
type Bombacopsis, the author subordinated the species
Bombacopsis amazonica A. Robyns, B. calophylla (K.Schum.)
A. Robyns, B. macrocalyx, B. nervosa (Ducke) A. Robyns,
B. paraensis (Ducke) A. Robyns, and B. stenopetala (Casar)
A. Robyns. This type is characterized especially by oblate or
peroblate shapes, by a salient equatorial “calotte”, constricted
or not constricted at the base, with a planaperturate amb.
In comparing our results with those of that author, we
found that ours did not allows results with those presented
here, does not enable B. calophylla and B. stenopetala to be
subordinated to the type Bombacopsis (with a reticulate
surface, the tectum has spines or other elevations; the muri
is simplicolumellate, duplicolumellate or pluricolumellate).
The species analyzed here showed pollen grains with a sexine that is rugulate in the apocolpium and microreticulate
to rugulate near the apertures, muri with sparse perforations and psilate, with perforations in the mesocolpium (B.
calophylla) or sexine in almost entire “vermiculate” surface
with isolated pilate elements, scabrate on the “calotte” (B.
glabra and B. stenopetala).
The type Chorisia speciosa is characterized by putting together pollen grains of Chorisia speciosa with large
polar area, 4(5)-colporate, very small colpi, lolongate endoaperture, reticulate sexine, high and simplicolumellate
muri. In the new classification, Chorisia was synonymized
with Ceiba. In this study, we analyzed three Ceiba species,
including Ceiba speciosa,. The characters found for Ceiba
Acta bot. bras. 28(3): 352-360. 2014.
crispiflora and C. erianthos in the present study are dissimilar to those of the type accepted by Salgado-Labouriau
(1973), especially in terms of the number of apertures (here
3- and 5-colporate) and the type of muri (here simplicolumellate). Only C. speciosa has attributes similar to those
of the type Chorisia speciosa. The type Eriotheca, created
by the same author, comprises seven species of Eriotheca,
among them, E. pentaphylla, the pollen grains of which
show characters similar to those of the type. To establish the
type Pseudobombax, Salgado-Labouriau (1973) analyzed
nine taxa of Pseudobombax, two of which (Pseudobombax
grandiflorum and P. marginatum) were also examined here
and can be subordinated to the type on the basis of their
pollen characters.
Nilsson & Robyns (1974) described a new species of
Eriotheca (E. obcordata) using specimens collected in Bahia. In their diagnosis, the pollen grains showed the typical
characters of the genus and of the Eriotheca species analyzed
here (E. pentaphylla).
Conclusion
On the basis of our findings, the following pollen characters can be considered the most diagnostic of the species
evaluated:
• pollen grains with a “calotte”, planaperturate, or
sinu-aperturate— in Bombacopsis, Pachira and Pseudobombax
• 3-colporate pollen grains—in all 11 species
• reticulate sexine—in nearly all of the species
• “vermiculate” sexine—in two of the three species of
Bombacopsis (B. glabra and B. stenopetala)
• rugulate sexine—in Bombacopsis calophylla
• sexine microreticulate on the entire surface—in
Spirotheca rivieri;
• sexine with difference in the ornamentation between
the apocolpium and the mesocolpium—in all of the
species, except Ceiba crispiflora, C. erianthos, C. speciosa and Eriotheca pentaphylla.
• Sexine with duplicolumellate muri and with one of
the columellae rows being shorter—in Ceiba speciosa.
In the pollen key presented here, most of the species
could be separated by palynological attributes, the only
exceptions being Bombacopsis glabra and B. stenopetala.
Therefore, we believe that the present study can contribute
to the taxonomic organization of the subfamily Bombacoideae, and that our data can be useful in future phylogenetic studies.
Acknowledgments
We are grateful to the staff of the Laboratory of Cell
Ultrastructure at the Biophysics Institute of the Universidade
359
Vanessa Holanda Righetti de Abreu, Claudia Barbieri Ferreira Mendonça and Vania Gonçalves-Esteves
Federal do Rio de Janeiro (UFRJ, Federal University of Rio
de Janeiro), for providing logistical support, and to Noêmia
R. Gonçalves, for providing technical assistance with the
scanning electron microscopy. This study received financial
support from the Brazilian Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, National Council for
Scientific and Technological Development; fellowship grants
to VHRA and VCE) and from the Fundação de Amparo a
Pesquisa do Estado do Rio de Janeiro (FAPERJ, Foundation
for the Support of Research in the State of Rio de Janeiro).
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