Journal of Seed Science, v.40, n.3, p.331-341 2018
http://dx.doi.org/10.1590/2317-1545v40n3199428
Physical, physiological and anatomical changes in Erythrina speciosa
Andrews seeds from different seasons related to the dormancy degree1
Debora Manzano Molizane2, Pricila Greyse dos Santos Julio3,
Sandra Maria Carmello-Guerreiro4, Claudio José Barbedo2*
ABSTRACT - Dormancy, a process that allows seeds to survive in adverse environments, needs to be broken for germination to start,
for example, by the disruption of the impermeable layer of seeds. Mature seeds of Erythrina speciosa present seed coat impermeability,
whose degree depends on the year of production. The objective of this study was to analyze the physical, physiological, anatomical,
and ultrastructural seed coat modifications, according to the environmental conditions in which seeds were produced, as well as the
seed sensitivity to treatments as for breaking dormancy. E. speciosa seeds were collected for six years in a row and were analyzed
as for dormancy degree. Moreover, chemical scarifications by different immersion times were applied on seeds from two production
years, as well as mechanical scarification, which was an efficient methodology to overcome dormancy. Different immersion times
by acid scarification were necessary to break dormancy in each harvest year. It was possible to conclude that the climatic conditions
under which the mother plant is submitted can influence the dormancy degree of E. speciosa seeds, but the expected anatomical
changes between dormant and non-dormant seeds were not found in seeds from this species.
Index terms: Leguminosae, sead coat impermeability, tropical tree species.
Alterações físicas, fisiológicas e anatômicas em sementes de Erythrina speciosa
Andrews de diferentes épocas, relacionadas com o grau de dormência
RESUMO - A dormência, um processo que permite que as sementes sobrevivam em ambientes adversos, precisa ser quebrada
para iniciar a germinação, por exemplo, pela ruptura da camada impermeável de sementes. Sementes maduras de Erythrina
speciosa apresentam impermeabilidade do tegumento da semente, cujo grau depende do ano de produção. O objetivo deste
estudo foi analisar as modificações físicas, anatômicas e ultraestruturais da casca da semente, de acordo com as condições
ambientais em que as sementes foram produzidas, bem como a sensibilidade das sementes a tratamentos para quebra de
dormência. Sementes de E. speciosa foram coletadas durante seis anos consecutivos e analisadas quanto ao grau de dormência.
Além disso, escarificações químicas por diferentes tempos de imersão foram aplicadas em sementes de dois anos de produção,
bem como escarificação mecânica, que foi uma metodologia eficiente para superar a dormência. Diferentes tempos de imersão
por escarificação ácida foram necessários para quebrar a dormência em cada ano de colheita. Concluiu-se que as condições
climáticas nas quais a planta-mãe é submetida podem influenciar no grau de dormência de sementes de E. speciosa, mas não
foram encontradas alterações anatômicas usualmente esperadas entre sementes dormentes e não-dormentes dessa espécie.
Termos para indexação: Leguminosae, impermeabilidade do tegumento, espécie arbórea tropical.
Introduction
The seed coat is an essential structure, both physically and
1
Submitted on 05/16/2018. Accepted for publication on 06/06/2018.
Instituto de Botânica, Núcleo de Pesquisa em Sementes, 04301-902 - São
Paulo, SP, Brasil.
3
Universidade Estadual de Mato Grosso do Sul, Cidade Universitária de
Dourados, 79804-970 - Dourados, MS, Brasil.
2
physiologically. As well as being a protective barrier between
the embryo and the environment, the structural and molecular
variations found among different coats deeply influence the
4
Instituto de Biologia, Universidade Estadual de Campinas, 13083-862 Campinas, SP, Brasil.
*Corresponding author <cjbarbedo@yahoo.com.br>
Journal of Seed Science, v.40, n.3, p.331-341, 2018
332
D. M. MOLIZANE et al.
physiology of the seed. Particularly, the variations found in
the coat thickness affect germination and dormancy (Coen
and Magnani, 2018).
Seed coat impermeability to water or gas is known as
physical exogenous dormancy and is a common phenomenon
among Fabaceae species. This type of dormancy can be
caused by several factors, which can be isolated or combined.
Among several causes, it is possible to mention the presence
of cuticles and waxes and the oxidation of phenolic
compounds found in the pigmented cells of the coat (MarcosFilho, 2015). In order to initiate the germination process, it
is necessary to have a rupture in this impermeable layer; this
can be done artificially by mechanical scarification or with
corrosive chemical substances, such as acids. For example,
the application of sulfuric acid for five minutes breaks the
dormancy of Stylosanthes humilis seeds (Chaves et al., 2017).
The environmental conditions to which the mother plant
is submitted can interfere with the seed maturation process,
causing changes in their physiological quality and also to
the establishment of physical dormancy (Hay et al., 2010;
Gama-Arachchige et al., 2011). Apparently, both the zygote
environment and the environment of the mother plant can act on
the establishment of dormancy, which may also cause changes
in fruit and seed tissues (Penfield and MacGregor, 2017). The
insolation degree, for example, may interfere with dormancy
intensity: environments with higher insolation double the
probability of producing dormant seeds (Souza et al., 2015).
Another important factor is temperature. Generally, seeds
formed under lower temperatures present a higher dormancy
degree, especially among annual species (Huang et al., 2017;
Penfield and MacGregor, 2017). However, these relations are
have not been fully proven yet, just like the relation with other
environmental factors, both regarding the degree of dormancy
established in seeds and their susceptibility to processes of
dormancy breaking. These were the objectives of this work,
with seeds of Erythrina speciosa (Leguminosae, Faboideae),
which were physically, physiologically, anatomically, and
ultrastructurally analyzed. E. speciosa is distributed throughout
the Cerrado and Atlantic Forest regions; it has an arboreal
aspect, between 3 and 5 meters in height, and is widely used
as an ornamental plant. Its seeds are tolerant to desiccation and
have an impermeable coat to water absorption (Pilatti et al.,
2010; Mello et al., 2010).
Material and Methods
Fruits of Erythrina speciosa were collected from 30 plants in
the Parque Cultural Catavento, in an urban area of São Paulo city,
in October 2010, 2011, 2012, 2013, 2014, and 2015. They were
Journal of Seed Science, v.40, n.3, p.331-341, 2018
immediately taken to the Seed Laboratory of the Botany Institute
(Laboratorio de Sementes do Instituto de Botânica), where seeds
were extracted manually. After that, seeds were analyzed as for
their moisture content and dry matter content by oven method at
103 °C for 17 hours (Brasil, 2009). The results were presented,
respectively, as percentage (wet basis) and mg.seed-1.
Germination tests were then conducted as follows:
without scarification treatments (SE) for seeds collected in
2012; with previous mechanical scarification (MS), as well
as SE, for the 2013, 2014, and 2015 collections; SE, MS and
scarification in sulfuric acid (H2SO4, PA, hereafter referred
to as acid scarification), with 0.5, 1, 3, 5, 10, 15, 40, and
60 minutes immersions for the 2010 and 2011 collections.
Germination tests were installed on paper rolls that had been
previously moistened with water by 2.5 times the paper weight
(Brasil, 2009) and incubated in a germination room regulated
at 25 ºC with a relative humidity of 70%. Evaluations were
carried out every other day for 30 days, and seeds that emitted
a primary root with an equal to or greater than 0.5 cm size
were recorded for the calculation of germination percentage
and mean germination time (Santana and Ranal, 2004).
In order to estimate intensity and imbibition rate, a
hydration curve was carried out with 20 seeds without
scarification, and also with a 15 and 40 minutes acid
scarification, for the 2010 and 2011 collections. Seeds were
placed to soak at 25 °C on a double sheet of germination
paper, as described above. Each seed was weighed initially
and after 24, 48, and 72 hours.
The opposite region to the hilum of intact seeds from all
collections (2010 to 2015) and also from all acid scarification
treatments from the 2010 and 2011 collections was analyzed
anatomically. For this, seed samples were fixed in FAA70 and
stored in 70% ethanol, infiltrated in plastic resin, transversely
sectioned with a disposable razor in an RM 2245 manual
rotary microtome, at a 7 μm thickness, and stained with 0.05%
toluidine blue (O’Brien et al., 1964). The analysis of the slides
was performed in an Olympus BX51 photomicroscope and
scaled images were obtained by an Olympus DP71 coupled
camera in the DPManager software. From these images,
differences presented by the coat of intact seeds from the
six collections were analyzed with the help of the ImageJ
software, and the following structures were measured: length,
wall and cuticle thickness of palisade exotesta cells and height
of hourglass cells and their underlying parenchyma.
Ultrastructural analyses were also carried out after the
acid scarification of the 2010 and 2011 collections. Seeds
were placed in metal capsules and then placed to dry in a
forced air circulation oven at 50 ºC for three days. Seeds with
no treatment to overcome dormancy were also analyzed. For
Dormancy in Erythrina speciosa seeds
the scanning electron microscope (SEM) analysis, seed testa
were cut with a scalpel blade and then adhered to the stub
with a conductive adhesive tape. The samples were plated
with ionized gold in argon atmosphere by a SCD 050 Bal-tec
metallizer, with a deposition time of 80 s and a current of 40
mA. After metallization, samples were scanned into a XL20
electron microscope for observation.
Climatic data (maximum and minimum temperature
and precipitation) from the six studied years were obtained
from the meteorological stations installed in the USP Parque
de Ciência e Tecnologia (Science and Technology Park
- 23º39’4”S 46º37’20”W). The ten-day period scale was
calculated through the mean at every ten days of the studied
years, for maximum and minimum temperature, and the sum at
every ten days for precipitation. The sequential water balance
was also calculated with precipitation data, using the model
proposed by Thornthwaite and Mather, in decreasing order of
a 125 mm water available capacity scale level (Leivas et al.,
2006; Rolim et al., 2007).
The experimental design was completely randomized.
Each treatment had four replications with 20 seeds for the
physiological analyses, and four replications of five seeds for the
physical analyses. Data were submitted to analysis of variance
(F test) and the means were compared by Tukey’s test, at a 5%
level, using the R statistical program. A correlation analysis of
the climatic data from the six collection years was also carried
out, with physical, physiological, and anatomical data.
Results and Discussion
The moisture content and dry matter content of
Erythrina speciosa seeds did not vary a lot between the
collections from the different years (9% to 12% moisture,
0.31 to 0.35 gDM.seed-1, Figures 1a and b), indicating that
they were collected when mature (Mello et al., 2010, 2011).
Germination results from the different samples showed the
variation in dormancy intensity, which was lower in the 2010
and 2014 collections (more than 40% of seeds germinating
without scarification) and higher in the 2011, 2012 and 2015
ones (less than 5%). This variation throughout the different
collections is expected, as already demonstrated for other
species, depending on the environmental conditions under
which seeds develop (Souza et al., 2015; Huang et al., 2017;
Penfield and MacGregor, 2017). The mean germination time
(MGT) presented differences according to the collection year
(Figure 1d), being higher in 2010, 2011 and 2012, and lower
in 2013, 2014 and 2015. When mechanically scarified, almost
all seeds germinated (Figure 1e), and this germination ocurred
in a very short period (Figure 1f).
333
The results obtained with the germination of seeds
scarified with sulfuric acid demonstrated the variation in
sensitivity to dormancy overcoming between seeds from
the 2010 and 2011 collections (Figure 1g). In order to reach
50% germination in the 2011 lot, 15 minutes of exposure
to the acid were required, whereas the same value was
exceeded in only 1 min in seeds from 2010. To reach values
close to 100%, only 15 min were necessary for the 2010
collection; on the other hand, in the 2011 collection, it took
40 minutes. Differences were also observed within the same
collection, by the imbibition curve (Figure 2). Seeds from
the 2010 collection, in the treatment with acid immersion for
15 and 40 minutes (Figures 2b, c), presented more soaking
seeds compared to the same treatment in the 2011 collection
(Figures 2e, f). It was also possible to observe a variation
between the 2010 seeds exposed to 15 minutes of acid; some
overcame dormancy in 24 to 48 minutes, and others needed
72 min, besides those that did not fully soak in the first 72
minutes (Figure 2b).
E. speciosa seeds have a dark brown coat. The testa
consists in an outer layer in high palisade, the exotesta, with
a cellular content that is rich in phenolic compounds and
with a light line close to the external periclinal wall; the
same was observed for E. lysistemon Hutch seeds (Manning
and Staden, 1985). Anatomical differences could not be
observed on intact seeds from all collections (Figure 3). The
measurements performed on the structures did not present
statistical differences that indicated a correlation with the
germination percentages of intact seeds. The cuticle that
covers the palisade cells (exotesta) of seeds from the 2010
collection (Figure 3a) is thinner than the seeds from the other
collections; this may facilitate the entry of water. However,
this reduction in cuticle thickness was not observed in the
2014 collection (Figure 3e). These results are different from
those obtained by Chai et al. (2016), who suggested that
palisade cell size and cuticle thickness may be responsible for
dormancy, due to water impermeability. Dormant seeds had a
dense light line, a thicker cuticle and larger palisade cells than
non-dormant seeds.
In the acid scarification treatments, it was possible to
observe anatomical differences (Figure 4). In the sulfuric acid
immersion periods, 0.5 min (collection 2010, Figures 4b; 5b)
and 1 min (collection 2011, Figures 4l; 5o) presented only cuticle
corrosion. The cuticle was removed with 1 min immersion for
2010 collection (Figures 4c; 5c), and after 10-15 min for 2011
collection (Figures 4o; 5s), which suggests that 2011 collection
had seeds with higher degree of dormancy. From 40 to 60 minutes
of immersion, it is possible to observe a slightly deep corrosion
of palisade cells (Figures 4h, i, q, r; Figures 5s, t).
Journal of Seed Science, v.40, n.3, p.331-341, 2018
D. M. MOLIZANE et al.
Dry matter (g.seed-1)
334
a
b
ab
ab
Figure 1. Physical and physiological responses of mature Erythrina speciosa seeds (a) Moisture content. (b) Dry matter. (c)
Seed germination without any treatment to overcome dormancy (Test.). (d) Mean germination time (MGT) of the
seed without any treatment (e) Germination of seeds with mechanical scarification (f) MGT of seeds with mechanical
scarification. (g) Germination of seeds with acid scarification for different periods (gray columns: 2010; black: 2011).
(h) MGT of seeds with acid scarification for different periods (gray columns: 2010; black: 2011). Same letter indicates
no statistical difference between two treatments. T = no treatment to overcome dormancy. m = Minutes.
Journal of Seed Science, v.40, n.3, p.331-341, 2018
335
Seed mass (g)
Dormancy in Erythrina speciosa seeds
Hours of imbibition
Figure 2. Weight gain in Erythrina speciosa Andrews seeds during imbibition in the two collected years, 2010 (a, b, c) and
2011 (d, e, f). (a and d) control treatment; (b and e) immersion in concentrated sulfuric acid for 15 minutes; (c e f)
immersion in concentrated sulfuric acid for 40 minutes. Each line indicates one seed.
Figure 3. Anatomy of the testa of mature E. speciosa seeds (stage 6), analyzed in six consecutive years. (a) 2010; (b) 2011; (c)
2012; (d) 2013; (e) 2014; (f) 2015. Scale 100μm ca - hourglass cells; cp - cells in palisades; pa - parenchyma; arrow
tip - cuticle; tip of the triangle - light line.
Journal of Seed Science, v.40, n.3, p.331-341, 2018
336
D. M. MOLIZANE et al.
Figure 4. Anatomy of the testa of mature E. speciosa seeds (stage 6), analyzed, collected, and submitted to acid scarification (a-i) 2010 collection; (j-r) 2011 collection. Scale 50μm. Coat detail: (a, j) control treatment, (b, k) 0.5 minute, (c, l) 1
minute, (d, m) 3 minutes, (e, n) 5 minutes, (f,o) 10 minutes, (g, p) 15 minutes, (h, q) 40 minutes, (i, r) 60 minutes.
Journal of Seed Science, v.40, n.3, p.331-341, 2018
Dormancy in Erythrina speciosa seeds
The cuticle was removed with 1-0 minute immersion for
2010 collection (Figures 4c, 5c), and after 10-15 minutes for
2011 collection (Figures 4o, 5s), which suggests that 2011
collection had seeds with higher degree of dormancy. From 40
and 60 minutes of immersion, it is possible to observe a slightly
deeper corrosion of palisade cells (Figures 4h, i, q, r; 5s, t).
In the 2010 collection, it was observed that acid
penetration occurred in points with lower resistance, between
the middle lamellae (Figures 5j, k, l); in 2011 (Figures 5v,
w, x), corrosion occurred in more extensive areas, but at a
lower depth, thus corroborating the dormancy difference
between the two collection years. In the ultrastructural
analyses, it was possible to observe differences in the sulfuric
acid immersion treatments, corroborating the observed
anatomical results. After the cuticle corrosion, in the 2010
collection, it was possible to observe that corrosions are
larger in extent and less deep. On the other hand, in the 2011
collection, coat corrosions were larger and deeper until the
40th minute of immersion. It is possible to observe that the
complete removal of the cuticle in the 2010 collection took
place within 1 minute of immersion in the acid, where the
germination percentage reached 24% more than the control
treatment. In the 2011 collection, the total removal of the
cuticle occurred in 10 minutes, exceeding by 35% more in
germination if related to the control treatment.
It is possible that the difference in the sulfuric acid
corrosion areas presented in the two collections promotes a
greater or lower penetration of water into internal regions of
seeds. Therefore, it can be assumed that compounds promoting
physical dormancy are not equally deposited across the testa
of the seeds. Palisade cell walls are composed of cellulose and
pectic compounds, marked by the magenta color of the walls
given by toluidine blue, without wall lignification. Pectins
are partially esterified glycosidic macromolecules; they are
abundant in the middle lamella, forming an adhesive between
the primary walls of plant cells. Pectin, in general, remains
stable at pH 3. This condition can be altered according to a pH
reduction, to the presence of Ca2+ ions and to the sugar content
of seeds. When pectin is in a strong acid medium, hydrolysis
occurs and there is the formation of a thermo-reversible gel
(Uenojo and Pastore, 2007; Belitz et al., 2009).
In the correlation analysis, no significance was observed
between the water stress due to the lack of water in the
soil and the degree of physical dormancy presented by E.
speciosa. Therefore, regardless of the water balance found
in the soil (Figure 6), the germination obtained in these
collections did not follow a pattern, as observed in the 2011
and 2014 collections.
A positive correlation was observed between moisture
337
content and germination: the higher the moisture content, the
higher the germination percentage without any scarification
treatment (Table 1). Results that correlated moisture content
and germination were observed in Geranium carolinianum
L. seeds, in which seeds that had been dried up to 11% of
water presented dormancy, whereas seeds with 13% did not
present dormancy (Gama-Arachchige et al., 2011). In E.
speciosa seeds, the correlation analysis showed a significant
response, so the higher the moisture content, the higher the
germination percentage.
Observing correlation results, May was an important
month for the dormancy of mature seeds of E. speciosa,
despite the fact that flowers were in development that month
and that they were in anthesis between June and August.
It was possible to observe a negative correlation between
relative humidity and moisture content in May. There was
also a negative correlation between germination percentage
and relative humidity in May. There may be chemical signals
during the period of floral formation that may affect dormancy
in the seeds that will develop. In September, a negative
correlation was observed between relative humidity and dry
matter. As seeds are already developing in this period, with
water being replaced by dry matter, relative humidity may
be important for the deposition of dry matter in the seed
cells. Changes in relative humidity (Figure 6) may affect sap
translocation in the plant. As relative humidity increases, the
water column movement and evaporation decrease, affecting
the translocation of the photosynthesized compounds.
Regardless of the water balance found in the soil (Figure 6),
the germination obtained in these samples did not follow a
pattern. As an example, in the 2011 and 2014 collections,
when water deficit occurred during maturation, there was also
a significant difference between the germination percentages,
2% and 40%, respectively.
Finally, the results obtained in this work allowed verifying
that different conditions during the formation of Erythrina
speciosa seeds cause differences in both their dormancy
degree and their sensitivity to breaking by acid scarification.
However, anatomically, seeds have the same head structures
and, consequently, associating coat impermeability to water
and structural changes, alone, seem to find no support in the
results. The structural change often associated with the coat
impermeability to the shell, that is, the loss of the lumen
of palisade cells by the thickening of the epidermal cells
(Smýkal et al., 2014), occurred in both dormant and nondormant seeds. Therefore, it is likely that the imposition of
dormancy is not necessarily related to these structures, and
some biochemical change may be necessary. It is more likely
for this impermeability to be due to structural and biochemical
Journal of Seed Science, v.40, n.3, p.331-341, 2018
338
D. M. MOLIZANE et al.
Figure 5. Micrographs obtained with a Scanning Electron Microscope (SEM) from the coat of Erythrina speciosa Andrews
seeds, collected in 2010 (a-l) and 2011 (m-x), in sulfuric acid immersion treatments. Coat detail: (a, m) Control
treatment, (b, n) 30 seconds, (c, o) 1 minute, (d, p) 3 minutes, (e, q) 5 minutes, (f, r) 10 minutes, (g, s) 15 minutes, (h,
t) 40 minutes, (i, u) 60 minutes. Overview: (j, v) control, (k, w) 40 minutes, (l, x) 60 minutes.
Journal of Seed Science, v.40, n.3, p.331-341, 2018
Dormancy in Erythrina speciosa seeds
339
Physiological
maturity
Precipitation (mm)
Physiological
maturity
Precipitation (mm)
Physiological
maturity
Precipitation (mm)
Physiological
maturity
Precipitation (mm)
Physiological
maturity
Precipitation (mm)
Physiological
maturity
Precipitation (mm)
Figure 6. Climatic conditions and water deficit during the 6-year maturation evaluation of Erythrina speciosa seeds.
Precipitation, ten-day period minimum and maximum temperatures (a-f). Water deficit and ten-day period relative
humidity (g-1). 2010 (a, g). 2011 (b, h). 2012 (c, i). 2013 (d, j). 2014 (e, k). 2015 (f, l).
Journal of Seed Science, v.40, n.3, p.331-341, 2018
340
Table 1.
D. M. MOLIZANE et al.
Correlation of the physiological and climatic data
occurred during the 6 years of maturation evaluated
in Erythrina speciosa seeds.
Relative
humidity in
May
-0.929*
Relative
humidity in
September
-0.368
-0.030
-0.332
-0.865*
-
-0.828*
-0.016
Germination
Moisture content
Dry matter
content
Germination
0.927*
* = significant at 5%. The correlation analysis was carried out with 61
variables, but only the variables that presented some significant correlation
were shown.
changes, possibly biochemical changes in specific regions, such
as the deposition of suberin and phenolic compounds in cells of
the palisade layer, as mentioned by Smýkal et al. (2014). On
the other hand, when seeds with different dormancy degrees
are subjected to sulfuric acid, the responses differ considerably,
probably due to the greater or lower penetration ease of the
acid into the palisade layers containing such compounds, due
to differences in their concentration in the testa cells. Thus,
although the structure of dormant and non-dormant seeds is not
different, structural differences may appear after the application
of the acid, as verified in this work.
Conclusions
Different conditions during the formation of Erythrina
speciosa seeds cause differences in both their dormancy degree
and their susceptibility to breakage by acid scarification.
Structural changes occurred equally in seeds with or without
dormancy, so they are not individually responsible for the
coat impermeability to water.
Acknowledgments
To the Biodiversity and Environment Post-Graduation
Program (Institute of Botany) for the opportunity granted
to the first author for his PhD; to the Conselho Nacional de
Desenvolvimento Científico e Tecnológico (CNPq) for the
doctorate scholarships, awarded to D.M. Molizane and the
productivity in research scholarship, awarded to S.M.CarmelloGuerreiro and C.J. Barbedo; to the Parque Cultural Catavento,
for the collection permission. To the Scanning Electron
Microscopy Laboratory of Institute of Botany.
Journal of Seed Science, v.40, n.3, p.331-341, 2018
References
BELITZ, H.D.; GROSCH, W.; SCHIEBERLE, P. Carbohydrates. In:
BELITZ, H.D.; GROSCH, W.; SCHIEBERLE, P. Food Chemistry.
Springer-Verlag Berlim Heidelberg, 2009. p.248–337.
BRASIL. Ministério da Agricultura, Pecuária e Abastecimento.
Regras para análise de sementes. Brasília: MAPA/ACS, 2009.
395p. http://www.agricultura.gov.br/arq_editor/file/2946_regras_
analise__sementes.pdf
CHAI, M.; ZHOU, C.; MOLINA, I.; FU, C.; NAKASHIMA, J.; LI,
G.; ZHANG, W.; PARK, J.; TANG, Y.; JIANG, Q.; WANG, Z.Y. A
class II KNOX gene, KNOX 4, controls seed physical dormancy.
Proceedings of the National Academy of Sciences, v.113, p.6997–
7002, 2016. https://doi.org/10.1073/pnas.1601256113
CHAVES, I.S.; SILVA, N.C.Q.; RIBEIRO, D.M. Effect of seed
coat on dormancy and germination in Stylosanthes humilis H.B.K.
seeds. Journal of Seed Science, v.39, p.114–122, 2017. http://dx.doi.
org/10.1590/2317-1545v39n2167773
COEN, O.; MAGNANI, E. Seed coat thickness in the evolution of
angiosperms. Cellular and Molecular Life Sciences, v.75, on line
first, 2018. https://doi.org/10.1007/s00018-018-2816-x
GAMA-ARACHCHIGE, N.S.; BASKIN, J.M.; GENEVE, R.L.;
BASKIN, C.C. Acquisition of physical dormancy and ontogeny of
the micropyle--water-gap complex in developing seeds of Geranium
carolinianum (Geraniaceae). Annals of Botany, v.108, p.51–64,
2011. https://10.1093/aob/mcr103
HAY, F.R.; SMITH, R.D.; ELLIS, R.H.; BUTLER, L.H.
Developmental changes in the germinability, desiccation tolerance,
hardseededness, and longevity of individual seeds of Trifolium
ambiguum. Annals of Botany, v.105, p.1035–1052, 2010. https://
www.ncbi.nlm.nih.gov/pubmed/20228084
HUANG, Z.; FOOTITT, S.; TANG, A.; FINCH-SAVAGE, W.E.
Predicted global warming scenarios impact on the mother plant to
alter seed dormancy and germination behaviour in Arabidopsis.
Plant, Cell and Environment, v.41, p.187–197, 2017. https://
onlinelibrary.wiley.com/doi/epdf/10.1111/pce.13082
LEIVAS, J.; BERLATO, M.; FONTANA, D. Risco de deficiência
hídrica decendial na metade sul do Estado do Rio Grande do Sul.
Revista Brasileira de Engenharia Agrícola e Ambiental, v.10, p.297–
407, 2006. http://dx.doi.org/10.1590/S1415-43662006000200022
MANNING, J.C.; VAN STADEN, J. The development and
ultrastructure of the testa and tracheid bar in Erythrina lysistemon
Hutch. (Leguminosae: Papilionoideae). Protoplasma, v.129, p.157–
167, 1985. http://link.springer.com/article/10.1007/BF01279913
MARCOS-FILHO, J. Fisiologia de sementes de plantas cultivadas.
Piracicaba: Fealq. 2015. 659p.
MELLO, J.I.O.; BARBEDO, C.J.; SALATINO, A.; FIGUEIREDORIBEIRO, R.C.L. Reserve carbohydrates and lipids from the seeds
of four tropical tree species with different sensitivity to desiccation.
Brazilian Archives of Biology and Technology, v.53, p.889–899,
2010. http://dx.doi.org/10.1590/S1516-89132010000400019
Dormancy in Erythrina speciosa seeds
MELLO, J.I.O.; CENTENO, D.C.; BARBEDO, C.J.; FIGUEIREDORIBEIRO, R.C.L. Changes in carbohydrate composition in seeds of
three tropical tree species submitted to drying and storage at freezing
temperature. Seed Science and Technology, v.39, p.465–480, 2011.
https://doi.org/10.15258/sst.2011.39.2.18
O’BRIEN, T.P.; FEDER, N.; MCCULLY, M.E. Polychromatic staning
of plant cell walls by toluidine blue. Protoplasma, v.59, p.368–373,
1964. http://link.springer.com/article/10.1007/BF01248568
PENFIELD, S.; MACGREGOR, D.R. Effects of environmental
variation during seed production on seed dormancy and germination.
Journal of Experimental Botany, v.68, p.819–825, 2017. https://doi.
org/10.1093/jxb/erw436
PILATTI, F.K.; AGUIAR, T.; SIMÕES, T.; BENSON, E.E.;
VIANA, A.M. In vitro and cryogenic preservation of plant
biodiversity in Brazil. In Vitro Cellular & Developmental Biology –
Plant, v.47, p.82–98, 2010. http://agris.fao.org/agris-search/search.
do?recordID=US201301944942
341
SANTANA, D.G.; RANAL, M.A. Análise da germinação: um
enfoque estatístico. Ed. UNB. 2004. 248p.
SMÝKAL, P.; VERNOUD, V.; BLAIR, M.W.; SOUKUP, A.;
THOMPSON, R.D. The role of the testa during develoment and in
establishment of dormancy of the legume seed. Frontiers in Plant
Science, v.5, article 351, 2014. https://www.ncbi.nlm.nih.gov/pmc/
articles/PMC4102250/
SOUZA, T.V.; TORRES, I.C.; STEINER, N.; PAULILO, M.T.S. Seed
dormancy in tree species of the Tropical Brazilian Atlantic Forest
and its relationships with seed traits and environmental conditions.
Brazilian Journal of Botany, v.38, p.243-264, 2015. https://link.
springer.com/content/pdf/10.1007%2Fs40415-014-0129-3.pdf
UENOJO, M.; PASTORE, G.M. Pectinases: Aplicações industriais
e perspectivas. Quimica Nova, v.30, p.388–394, 2007. http://dx.doi.
org/10.1590/S0100-40422007000200028.
ROLIM, G.D.E.S.; CAMARGO, M.B.P.; LANIA, D.G.; MORAES,
J.F.L. Classificação climática de Köppen e de Thornthwaite e sua
aplicabilidade na determinação de zonas agroclimáticas para o
Estado de São Paulo. Bragantia, v.66, n.4, p.711–720, 2007. http://
www.scielo.br/pdf/brag/v66n4/22.pdf
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distribution, and reproduction in any medium, provided the original work is properly cited.
Journal of Seed Science, v.40, n.3, p.331-341, 2018