Morphological Studies of the Euterpe oleracea Mart. Seeds
B.G. Santos Filho,
C.F. Oliveira Neto,
The aim of this research is to describe the morpho-anatomy
of Euterpe oleracea Mart. seed. The samples with 30 seeds (0, 10,
30 days after the beginning of the germination process), in which the
seeds were placed in plastic boxes with sand as substrate and immediately
introduced in germination chamber under 30 °C, being irrigated daily
with distilled water. The morphological and anatomical observations of
the seed were carried out in the times 0, 10 and 30 and 0 days of germination,
respectively. This seed has ruminated endosperm, solid, besides being
constituted by large cellular walls, with several pit primary fields.
The testa is ruminated, constituted by fine cellular walls, divided in
three layers (external, medium and internal), it being that the medium
layer has vascular bundles. The embryo is conic, basal and axial linear,
with two regions, being a proximal (hypocotyl-radicle axis) and other
The species Euterpe oleracea Mart. has economical importance to
the Amazon region, because with the fruit pericarp several food products
and energy drinks with economic potential in the Brazil and world are
manufactured (Oliveira et al., 2002). The palm and its derivatives
might be utilized in the pulp production, animal ration, forest, medicine,
natural colorants, besides producing heart of palm, commercialized mainly
for the export, in which 95% of all hearts of palm produced in the Brazil
is extracted of this palm (Oliveira and Muller, 1998).
The distribution of this palm in the Brazil occur mainly in the states
of the Pará, Amazonas, Maranhão and Amapá, besides
to be found also in the Colombia, Equator, Guiana and Venezuela (Nascimento,
2006). Moreover, Euterpe oleracea has with habitat humid environment
and soil partially flood, present pined leaf, flowers intrafoliars and
the fruits are globosa drupes with pericarp green or lilac, when immature
or mature, respectively (Jardim et al., 2004; Oliveira et al.,
2002; Rogez, 2000).
The seed is the result of the development of the fertilized ovule through
the process of double fecundation, being in Angiosperms, the mature seed
is basically constituted of the embryo, endosperm and testa, in which
the embryo develops through the diploid zygote formed by the fusion of
one gametic nucleus and the oosfere, besides triploid endosperm originated
from the combination of two polar nucleus with the second gametic nucleus
(triple fusion) and the tegument or testa, formed by the integuments that
involve the ovule (Cardoso, 2004).
The palm seeds are round or elliptic, are sticked to pericarp or simply
free. When they are free, the seminal tegument is relatively thick and
shows one opercule, in which it corresponds to the scar on the surface,
next the micropyle that becomes visible during the germination (Alves
and Demattê, 1987; Nascimento et al., 2007). Generally the
cavity of the palm fruits is filled in by only one hard and dense seed
constituted of the tegument derived from the ovule wall that covers the
endosperm, in which it is a mass of nutritive tissue that is fitted in
one small and soft embryo (Ferreira and Borghetti, 2004; Lorenzi et
The objective of this research is to describe the morpho-anatomy of Euterpe
oleracea Mart. seed, it aimed to contribute subsequent studies with
the structure function showed.
MATERIALS AND METHODS
Plant material and procedures: The Euterpe oleracea Mart.
seed were harvested of fruits and transported to the Laboratório
de Fisiologia Avançada of the Universidade Federal Rural da Amazônia
(UFRA), city of Belém, state of Pará, Brasil (01°27`S
and 48°26W), it being the experiments were conducted during
the months January and February of 2006. The seeds were washed in neutral
liquid detergent and running water, for to remove impurities and fruit
residues in pericarp and immediately the mesocarp was removed with the
objective to avoid fermentations provoked by fruit residues and fungus
proliferation (Carvalho et al., 1998). The samples with 30 seeds
(0, 10, 30 days after the beginning of the germination process, in which
it was utilized plastic boxes with the dimensions (lengthXwidthXheight;
35X25X7 cm, respectively) previously sterilized with sodium hypochlorite
at 2% and the substrate was washed and autoclaved sand (120°C, 1 atm
by 20 min). The seeds were uniformly distributes and placed in the substrate
with seed opercule in the horizontal position and profundity of 2 cm (Aguiar
and Mendonça, 2002). The plastic boxes containing the seeds and
substrate were placed in germination chamber under temperature of 30°C,
being irrigated daily with distilled water.
Seed morphology: The observations were carried out for 0, 10 and
30 days of germination. The seeds were removed of the substrate, washed
in neutral liquid detergent and running water, after immersing in sodium
hypochlorite at 2% by the period of 72 h. The observations were carried
out at stereoscope photographic (model Motic Digital Microscope DM 148)
with the software Motic imagens plus 2,0 ML of the Museu Paraense Emílio
Goeldi (MPEG), Belém, Brasil.
Seed anatomy: The observation of the seeds was carried out in
0 days of germination, in which were removed of the substrate, washed
in neutral liquid detergent and transversal histologic cuts were carried
out in endosperm. In the confection of the histological blades aqueous
glycerin at 50% was utilized (Purvis et al., 1964). The photomicrographs
were carried out at three increases (100, 200 and 400X), utilizing stereomicroscope
(model Olympus BX 41-FL-III) with the software Applied Spectral Imaging
in the Universidade Federal do Pará (UFPA), Belém, Brasil
and photomicroscope (model Zeiss XZ-305) of the Museu Paraense Emilio
Goeldi (MPEG), Belém, Brasil.
The Euterpe oleracea Mart. seed with 0 days after the beginning
of the germination process present testa of the ruminated type (Fig.
1a), in which this rumination is not restricted to the testa, but
also catches the endosperm, leaving this structure with irregular aspect,
being denominated ruminated endosperm (Fig. 1b). This
rumination appears as radial lines that arise in the seed outskirt and
goes in the direction toward center (Fig. 1c and d).
The embryo is small, conic, basal, being of the axial linear type and
is involved by abundant endospermatic tissue (Fig. 1e).
It has two regions, one being proximal, more wide and dark described as
hypocotil-radicle axis of yellow-white color and the other is distal more
narrow and bright of white-pale that corresponding to simple cotyledon
It were showed in the seeds with 10 days the breakthrough of the seed
opercule (circular testa) at function of the protrusion of the cotyledonal
bud, being a bulbose structure originated of the dilatation of the radicle-hypocotil
axis that loads the meristematic pole in the extremity (Fig.
2a). In the seeds with 30 days after the beginning of the germination
process was showed the primary root and subsequently the secondarys are
originates from besides seedling stem that is responsible of originating
the first leaf denominated eophyll (Fig. 2b), as well
as the embryo distal portion, the growth and dilatation of the cotyledon
originating the haustorium, a globule structure with spongy aspect, in
which is responsible of the absorption of the sugars coming from degradation
of the endosperm reserve wall occurs (Fig. 2c).
The optical microscopy demonstrated that the center region of the seed
testa projection is constituted of extended cells, with thin and irregular
walls, besides abundant cytoplasmatic content (Fig. 3a).
However the general visualization of the testa projection in the optical
microscope, reveals that this is formed by the center region, with pale
color and approximately eight layers of parenchymatical cells, coved in
the top part that in the lower by an epiderm formed by small cells, in
which probably great amount of tannin cell content accumulate, in which
it is responsible for the dark aspect of this region (Fig.
The transversal section of seed endosperm reveal that this is voluminous
(Fig. 3c), constituted by cells with irregular and
large walls, rich in pit primary fields and that takes up greater part
of total cell volume.
The Fig. 4a reveal that the seed have the testa as
main mechanical layer that cover and protect the endosperm, however this
structure has not tegmen. According the classification of Corner (1976) this seed is testal and with one tegument. The Fig. 4b
reveal a general vision of the endosperm longitudinal section, testa and
projection testa of Euterpe oleracea seed. It was showed a penetration
of testa projection in the seed endosperm, probably carrying transport
function. The Fig. 4c reveal the longitudinal section
of seed endosperm, in which this tissue is formed by elongated cells,
with thick cellular wall and greater number of pit primaries and cytoplasm
that was strongly stained.
The ruminated endosperm showed occurred by consequence of the growth
or by to have folds in the seed testa that originate projections that
penetrate in the young endosperm interior under development phase. Similar
results were showed by Beltrati and Paoli (2003) and Neto (2004) in several
palm seeds, in which both testa and seed endosperm of the Euterpe oleracea
are ruminated. Moreover, the description of embryo carried out in this
study corroborate the research of Beltrati and Paoli (2003).
Similar germinative behavior was found in seeds of the Euterpe precatoria
(Aguiar and Mendonça, 2001, 2002, 2003) and Phoenix roebelenii
(Iossi, 2002). These results corroborate the studies carried out by De
Paula (1975), in which the testa projections are formed by 8 to 13 cell
layers, with fine and pectic-cellulosic walls and rich reserve substance.
According to Lorenzi et al. (1996) the folds or invaginations
of testa projections of palm seeds located in endosperm leave this tissue
with irregular aspect, denominate ruminated endosperm (Beltrati and Paoli,
2003). These testa invaginations in the endosperm of Euterpe oleracea
seed originate cell radial lines (testa projections) that distribute
through the tissue and carry out some function of carbohydrate conduction
coming from the degradation of the endosperm reserves in the direction
to embryo haustorium during the germination (Neto, 2004), however this
author describe that only the seed testa is ruminated, not the endosperm.
This way, future studies on the endosperm and testa ontogeny of this seed
are important to confirm the origin of rumination. The results of this
investigation are similar with the findings in the description seeds of
Euterpe precatoria (Aguiar and Mendonça, 2003), Euterpe
edulis (Panza et al., 2004), as well as Euterpe oleracea
(Neto, 2004), in which belonging to same genus of Euterpe oleracea.
This way, this study reveals that not exist morphological differences
among these seeds.
According to De Paula (1975) the immature seeds, have the endosperm with
fine walls, pectic-cellulosics, storage of lipid bodies and rare starch
grains. However in mature seeds the endosperm is constituted of large
walls, rich in celluloses and hemicelluloses, with pits that have the
capacity of lipid and hemicellulose storage.
The seed testa is constituted by several cell layers that might be organized
in three groups: external layer, medium layer and internal layer. The
external layer is formed by the external epiderm of testa and corresponds
the layer with greater cells, large walls, lignified and rich in tannin,
phenolic compost that is responsible for the seed color, increase of the
testa stiffness and protection against predatories and microorganisms
(Beltrati and Paoli, 2003).
The medium layer is the testa mesophyll, constituted by greater cells,
with large walls, lignified and that probably has mainly the characteristic
of cell growth by elongation, originating testa projections, which penetrate
in endospermatic tissue. A strong evidence that confirms the cell elongation
might the fact of the mesophyll cells that has greater and roundly aspect,
besides large and lignified walls, compared to the testa external layer.
Whereas the cells that constitute the testa projections are elongated,
with fine and irregular walls. Other important characteristic of the testa
mesophyll is the presence of vascular bundles in the projection regions,
being showed that the testa projections has probable function of carbohydrate
transport, coming from the endosperm reserve degradations in the direction
to embryo haustorium during the germination.
The internal layer is an internal epiderm, constituted by an irregular
single file of the small cells, with fine and lignified walls and rich
in tannin cell content. As well as it covers internally all the testa
mesophyll and the projections penetrated in the endosperm. Similar results
were found in Euterpe precatoria (Aguiar and Mendonça, 2003),
however in this study the mesophyll cells and seed internal layer do not
The Euterpe oleracea Mart. seed has solid ruminated endosperm,
besides is constituted by large cellular walls, with several pit primary
fields. The testa is ruminated, constituted by fine cellular walls, divided
in three layers (external, medium and internal), being that the medium
layer has vascular bundles. The embryo is conic, basal and axial linear,
with two regions, being a proximal (hypocotil-radicle axis) and other
The present study make part of M.S. Thesis and this project (02/97-T.A.
No. 27) was funded by the Fundação de Apoio à Pesquisa,
Extensão e Ensino em Ciências Agrárias (FUNPEA), besides
counting with the infra-structures of the Universidade Federal Rural da
Amazônia (UFRA) and Museu Paraense Emílo Goledi (MPEG) and
Universidade Federal do Pará (UFPA).
1: Aguiar, M.O. and M.S. de Mendonca, 2001. Morphological aspects and development of the seedling of Euterpe precatoria Mart. Acai-do-Amazonas). Acta Amazonica, 31: 687-691.
Direct Link |
2: Aguiar, M.O. and M.S. Mendonça, 2002. Morpho-anatomy aspects of Euterpe precatoria Mart. embryo during the germinative process. Acta Bot. Brasalica, 16: 241-249.
3: Aguiar, M.O. and M.S. Mendonça, 2003. Morpho-anatomy of Euterpe precatoria Mart. seed (palmae). Rev. Bras. Sem., 25: 1-9.
4: Alves, M.R.P. and M.E.S.P. Demattê, 1987. Palms: Botanical features and evolution. Fundação Cargill, Campinas-SP.
5: Beltrati, C.M. and A.A.S. Paoli, 2003. Seed. In: Plant Anatomy, Apezzato-da-glória, B. and S.M. Carmello-Guerreiro (Eds.). Universidade Federal de Viçosa, Viçosa, pp: 399-424.
6: Cardoso, V.J.M., 2004. Germination. In: Plant Physiology, Kerbauy, G.B. (Ed.). Guanabara Koogan, Rio de Janeiro.
7: Carvalho, J.E.U., W.M.O. Nascimento and C.H. Muller, 1998. Physical features and seed germination of fruit species native of Amazon. Embrapa-CPATU, Belém.
8: Corner, E.J.H., 1976. The seeds of dicotyledons. Cambridge University, London.
9: De Paula, J.E., 1975. Anatomy of Euterpe oleracea Mart. (Palm of Amazon). Acta Amazônica, 5: 265-278.
10: Ferreira, A.G. and F. Borghetti, 2004. Germination: From basic to applied. Artmed, Porto Alegre.
11: Iossi, E., 2002. Morphology and seed germination of tamareira-anã (Phoenix roebelenii o' brien). M.S. Thesis, Universidade Estadual Paulista, Brasil.
12: Jardim, M.A.G., L. Mourão and M. Grossmann, 2004. Açaí (Euterpe oleracea Mart.): Possibility and limits for the development sustainable in the Amazon region. Museu Paraense Emílio Goeldi, Belém.
13: Lorenzi, H., H.M. Souza, J.T.M. Costa, L.S.C. Cerqueira and N. Van Behr, 1996. Palms of Brazil: Natives and exotics. Plantarum, Nova Odessa.
14: Nascimento, W.M.O., 2006. Conservation of açaí (Euterpe oleracea Mart.) seeds. Ph.D Thesis, Escola Superior Luiz de Queiroz, Brasil.
15: Nascimento, W.M.O., A.D.L.C. Novembre and S.M. Cícero, 2007. Physiological consequences of desiccation in Euterpe oleracea Mart. seeds. Rev. Bras. Sementes, 29: 38-43.
Direct Link |
16: Neto, M.A.M., 2004. Anatomic and biochemical characterization of Euterpe oleracea Mart. seed during the germination in anoxia and normoxia conditions. Ph.D Thesis, Universidade Federal de Lavras, Brazil.
17: Oliveira, M.S.P. and A.A. Muller, 1998. Germoplasm selection of Euterpe oleracea for fruits. Embrapa-CPATU, Belém.
18: Oliveira, M.S.P., J.E.U. Carvalho, W.M.O. Nascimento and C.H. Muller, 2002. Cultive of Açaizeiro Aimed the Fruit Production. 1st Edn., Embrapa Amazônia Oriental, Belém.
19: Panza, V., V. Lainez and S. Maldonado, 2004. Seed structure and histochemistry in the palm Euterpe edulis. Bot. J. Linnean Soc., 145: 445-453.
CrossRef | Direct Link |
20: Purvis, M.J., D.C. Collier and D. Walls, 1964. Laboratory Techniques in Botany. Butterworths, London.
21: Rogez, H., 2000. Açaí: Prepare, composition and conservation breeding. UFPA, Belém.