Abstract

Ananas ananassoides (Baker) L.B.Sm. is a wild pineapple, commonly found in the savannas. This study aimed to describe the morpho-anatomy and histochemistry of its seed. The observations were made in the longitudinal and transverse sections, using an optical microscope. The cell arrangement in the seed coat, ripples in the integument, the ratio of embryo size and endosperm amount, and the number of strata in the aleurone layer are anatomical characteristics that may contribute to distinguishing this species. The starch in the endosperm, lipids and proteins in the embryo, constitute the seed's main nutritional reserves. The homogeneous embryo and phenolic compounds present in the seed coat and in the aleurone layer possibly contribute to the dormancy in this species. This study presents information relevant to the taxonomy and physiology of A. ananassoides, which represents contributions to the global knowledge of this species with a high potential as ornamental.

Keywords:
embryo; endosperm; pineapple; seed coat

Resumo

Ananas ananassoides (Baker) L.B.Sm. é um abacaxi silvestre, comumente encontrado nas savanas. Este estudo teve como objetivo descrever a morfoanatomia e histoquímica de sua semente. As observações foram feitas nos cortes longitudinais e transversais, em microscópio óptico. O arranjo celular no tegumento, as ondulações no tegumento, a relação entre o tamanho do embrião e a quantidade de endosperma, e o número de estratos na camada de aleurona são características anatômicas que podem contribuir para a distinção dessa espécie. O amido do endosperma e os lipídios e proteínas do embrião constituem as principais reservas nutricionais da semente. O embrião homogêneo e os compostos fenólicos presentes no tegumento e na camada de aleurona possivelmente contribuem para a dormência nessa espécie. Este estudo apresenta informações relevantes para a taxonomia e fisiologia de A. ananassoides, sendo contribuições valiosas para o conhecimento global dessa espécie com alto potencial ornamental.

Palavras-chave:
abacaxi; embrião; endosperma; tegumento

1. Introduction

Pineapple belongs to the large and diverse Bromeliaceae family, which contains about 3700 species (Gouda and Butcher, 2022GOUDA, E.J. and BUTCHER, D., 2022 [viewed 11 May 2022]. A list of accepted Bromeliaceae names [online]. Utrecht University Botanic Gardens. Available from: http://bromeliad.nl/bromNames/
http://bromeliad.nl/bromNames/... ). The bromeliads contribute to ecosystem stability due to their high levels of specialization (Benzing, 2000BENZING, D.H., 2000. Bromeliaceae: profile of an adaptive radiation. New York: Cambridge University Press, 710 p. http://dx.doi.org/10.1017/CBO9780511565175.
http://dx.doi.org/10.1017/CBO97805115651... ) and to important ecological role caused by their biotic interactions (Pederassi et al., 2012PEDERASSI, J., LIMA, M.S.C.S., PEIXOTO, O.L. and SOUZA, C.A.S., 2012. The choice of bromeliads as a microhabitat by Scinax argyreornatus (Anura, Hylidae). Brazilian Journal of Biology = Revista Brasileira de Biologia, vol. 72, no. 2, pp. 229-233. http://dx.doi.org/10.1590/S1519-69842012000200001. PMid:22735128.
http://dx.doi.org/10.1590/S1519-69842012... ; Mendes et al., 2020MENDES, P.M.S., LANSAC-TÔHA, F.M., MEIRA, B.R., OLIVEIRA, F.R., VELHO, L.F.M. and LANSAC-TÔHA, F.A., 2020. Heterotrophic flagellates (Amorpha and Diaphoretiches) in phytotelmata bromeliad (Bromeliaceae). Brazilian Journal of Biology = Revista Brasileira de Biologia, vol. 80, no. 3, pp. 648-660. http://dx.doi.org/10.1590/1519-6984.218742. PMid:31644658.
http://dx.doi.org/10.1590/1519-6984.2187... ). In fact, Paula Júnior et al. (2017)PAULA JÚNIOR, A.T., ROSA, B.F.J.V., ALVES, R.G. and DIVINO, A.C., 2017. Aquatic invertebrates associated with bromeliads in Atlantic Forest fragments. Biota Neotropica, vol. 17, no. 1, pp. 1-7. http://dx.doi.org/10.1590/1676-0611-bn-2016-0188.
http://dx.doi.org/10.1590/1676-0611-bn-2... suggest including bromeliads in policies to protect biodiversity, considering their importance in maintaining biodiversity even in altered landscapes exposed to adverse conditions.

Ananas genus bear fused flowers that develop into the iconic sorose fruit that contributes to the aesthetic appeal of pineapple (d’Eeckenbrugge et al., 1997D’EECKENBRUGGE, G.C., LEAL, F. and DUVAL, M.F., 1997. Germplasm resources of pineapple. In: J. JANICK, ed. Horticultural reviews. New York: John Wiley and Sons, pp. 133-175.) and has several taxa with historical and modern economic importance (VanBuren, 2018VANBUREN, R., 2018. Genomic relationships, diversity, and domestication of Ananas taxa. In: R. MING, ed. Genetics and genomics of pineapple-plant genetics and genomics-crops and models. Cham: Springer, vol. 22, pp. 259-272. http://dx.doi.org/10.1007/978-3-030-00614-3_18.
http://dx.doi.org/10.1007/978-3-030-0061... ). Potential uses have been explored for species of the genus Ananas, including the production of fibers to produce articles for the automotive industry (Zah et al., 2007ZAH, R., HISCHIER, R., LEÃO, A.L. and BRAUN, I., 2007. Curauá fibers in the automobile industry–a sustainability assessment. Journal of Cleaner Production, vol. 15, no. 11-12, pp. 1032-1040. http://dx.doi.org/10.1016/j.jclepro.2006.05.036.
http://dx.doi.org/10.1016/j.jclepro.2006... ), the production of polymeric composites (Souza et al., 2017aSOUZA, C.P.F., FERREIRA, C.F., SOUZA, E.H., SENA NETO, A.R., MARCONCINI, J.M., LEDO, C.A.S. and SOUZA, F.V.D., 2017a. Genetic diversity and ISSR marker association with the quality of pineapple fiber for use in industry. Industrial Crops and Products, vol. 104, pp. 263-268. http://dx.doi.org/10.1016/j.indcrop.2017.04.059.
http://dx.doi.org/10.1016/j.indcrop.2017... ) manufacture of paper (Marques et al., 2007MARQUES, G., GUTIÉRREZ, A. and RIO, J.C., 2007. Chemical characterization of lignin and lipophilic fractions from leaf fibers of curaua (Ananas erectifolius). Journal of Agricultural and Food Chemistry, vol. 55, no. 4, pp. 1327-1336. http://dx.doi.org/10.1021/jf062677x. PMid:17253715.
http://dx.doi.org/10.1021/jf062677x... ), proteolytic enzymes (Ramli et al., 2021RAMLI, A.N.M., HAMID, H.A., ZULKIFLI, F.H., ZAMRI, N., BHUYAR, P. and MANAS, N.H.A., 2021. Physicochemical properties and tenderness analysis of bovine meat using proteolytic enzymes extracted from pineapple (Ananas comosus) and jackfruit (Artocarpus heterophyllus) by-products. Journal of Food Processing and Preservation, vol. 45, no. 11, p. e15939. http://dx.doi.org/10.1111/jfpp.15939.
http://dx.doi.org/10.1111/jfpp.15939... ) and secondary metabolites of great value for the cosmetic, pharmaceutical and food industry (Manetti et al., 2009MANETTI, L.M., DELAPORTE, R.H. and LAVERDE JUNIOR, A., 2009. Metabólitos secundários da família Bromeliaceae. Química Nova, vol. 32, no. 7, pp. 1885-1897. http://dx.doi.org/10.1590/S0100-40422009000700035.
http://dx.doi.org/10.1590/S0100-40422009... ; Banerjee et al., 2018BANERJEE, S., RANGANATHAN, V., PATTI, A. and ARORA, A., 2018. Valorisation of pineapple wastes for food and therapeutic applications. Trends in Food Science & Technology, vol. 82, pp. 60-70. http://dx.doi.org/10.1016/j.tifs.2018.09.024.
http://dx.doi.org/10.1016/j.tifs.2018.09... ), besides its great ornamental potential (d’Eeckenbrugge and Duval, 2009D’EECKENBRUGGE, G.C. and DUVAL, M.F., 2009. The domestication of pineapple: context and hypotheses. Pineapple News, vol. 16, pp. 15-27.; Sanewski, 2009SANEWSKI, G.M., 2009. Breeding Ananas for the cut-flower and garden markets. Acta Horticulturae, vol. 822, pp. 71-78. http://dx.doi.org/10.17660/ActaHortic.2009.822.7.
http://dx.doi.org/10.17660/ActaHortic.20... ; Souza et al., 2012SOUZA, E.H., SOUZA, F.V.D., COSTA, M.A.P.C., COSTA JUNIOR, D.S., SANTOS-SEREJO, J.A., AMORIM, E.P. and LEDO, C.A.S., 2012. Genetic variation of the Ananas genus with ornamental potential. Genetic Resources and Crop Evolution, vol. 59, no. 7, pp. 1357-1376. http://dx.doi.org/10.1007/s10722-011-9763-9.
http://dx.doi.org/10.1007/s10722-011-976... ). Bromeliads are among the most valuable ornamental plants (Negrelle et al., 2012NEGRELLE, R.R.B., ANACLETO, A. and MITCHELL, D., 2012. Bromeliad ornamental species: conservation issues and challenges related to commercialization. Acta Scientiarum. Biological Sciences, vol. 34, no. 1, pp. 91-100. http://dx.doi.org/10.4025/actascibiolsci.v34i1.7314.
http://dx.doi.org/10.4025/actascibiolsci... ), and according to Souza et al. (2017b)SOUZA, E.H., VERSIEUX, L.M., SOUZA, F.V.D., ROSSI, M.L., COSTA, M.A.P.C. and MARTINELLI, A.P., 2017b. Interspecific and intergeneric hybridization in Bromeliaceae and their relationships to breeding systems. Scientia Horticulturae, vol. 223, pp. 53-61. http://dx.doi.org/10.1016/j.scienta.2017.04.027.
http://dx.doi.org/10.1016/j.scienta.2017... , the generation of new hybrids for ornamental use can reduce extractive activity and its negative impacts on natural populations. Therefore, it is important to develop studies focused on seeds since they are ideal structures to store the gene pool of a species, guaranteeing the conservation of genetic variability (Gosling, 2003GOSLING, P.G., 2003. Viability testing. In: R.D. SMITH, J.B. DICKIE, S.L. LININGTON, H.W. PRITCHARD and R.J. PROBERT, eds. Seed conservation: turning science into practice. Kew: Royal Botanic Gardens, pp. 445-481.).

Ananas ananassoides (Baker) L.B.Sm. is the most common and diverse form of wild pineapple, and it is the most likely ancestor of the cultivated pineapple (d’Eeckenbrugge et al., 2011D’EECKENBRUGGE, G.C., SANEWSKI, G.M., SMITH, M.K., DUVAL, M.F. and LEAL, F., 2011. Ananas. In: C. KOLE, ed. Wild crop relatives: genomic and breeding resources-tropical and subtropical fruits. Berlin: Springer, pp. 21-41. http://dx.doi.org/10.1007/978-3-642-20447-0_2.
http://dx.doi.org/10.1007/978-3-642-2044... ). According to Souza et al. (2012)SOUZA, E.H., SOUZA, F.V.D., COSTA, M.A.P.C., COSTA JUNIOR, D.S., SANTOS-SEREJO, J.A., AMORIM, E.P. and LEDO, C.A.S., 2012. Genetic variation of the Ananas genus with ornamental potential. Genetic Resources and Crop Evolution, vol. 59, no. 7, pp. 1357-1376. http://dx.doi.org/10.1007/s10722-011-9763-9.
http://dx.doi.org/10.1007/s10722-011-976... , A. ananassoides can be used as parents in the genetic breeding program for the generation of pineapple ornamental hybrids. This species is a terrestrial and perennial bromeliad (Silveira et al., 2010SILVEIRA, F.A., SANTOS, J.C. and FERNANDES, G.W., 2010. Seed germination ecophysiology of the wild pineapple, Ananas ananassoides (Baker) L.B.Sm. (Bromeliaceae). Acta Botanica Brasílica, vol. 24, no. 4, pp. 1100-1103. http://dx.doi.org/10.1590/S0102-33062010000400026.
http://dx.doi.org/10.1590/S0102-33062010... ; Stahl et al., 2012STAHL, J.M., NEPI, M., GALETTO, L., GUIMARÃES, E. and MACHADO, S.R., 2012. Functional aspects of floral nectar secretion of Ananas ananassoides, an ornithophilous bromeliad from the Brazilian savanna. Annals of Botany, vol. 109, no. 7, pp. 1243-1252. http://dx.doi.org/10.1093/aob/mcs053. PMid:22455992.
http://dx.doi.org/10.1093/aob/mcs053... ) found in Neotropical savannas or inland low-shade forests, growing on soils with limited water-holding capacity (sand, rocks). It forms populations of variable densities and regeneration can occur vegetatively and sexually (through seed production) (d’Eeckenbrugge and Leal, 2003D’EECKENBRUGGE, G.C. and LEAL, F., 2003. Morphology, anatomy and taxonomy. In: D.P. BARTHOLOMEW, R.E. PAULL and K.G. ROHRBACH, eds. The pineapple: botany, production and uses. New York: Cabi-Publishing, pp. 13-32. http://dx.doi.org/10.1079/9780851995038.0013.
http://dx.doi.org/10.1079/9780851995038.... ; d’Eeckenbrugge et al., 2011D’EECKENBRUGGE, G.C., SANEWSKI, G.M., SMITH, M.K., DUVAL, M.F. and LEAL, F., 2011. Ananas. In: C. KOLE, ed. Wild crop relatives: genomic and breeding resources-tropical and subtropical fruits. Berlin: Springer, pp. 21-41. http://dx.doi.org/10.1007/978-3-642-20447-0_2.
http://dx.doi.org/10.1007/978-3-642-2044... ). This species is considered a pioneer for presenting small and photoblastic seeds and higher germination rates in areas with high luminosity (Silveira et al., 2010SILVEIRA, F.A., SANTOS, J.C. and FERNANDES, G.W., 2010. Seed germination ecophysiology of the wild pineapple, Ananas ananassoides (Baker) L.B.Sm. (Bromeliaceae). Acta Botanica Brasílica, vol. 24, no. 4, pp. 1100-1103. http://dx.doi.org/10.1590/S0102-33062010000400026.
http://dx.doi.org/10.1590/S0102-33062010... ).

Studies on the characterization of seeds from native species are important for the maintenance of biodiversity as they can support programs for the recovery of degraded areas (Oliveira et al., 2006OLIVEIRA, A.K.M., SCHLEDER, E.J. and FAVERO, S., 2006. Caracterização morfológica, viabilidade e vigor de sementes de Tabebuia aurea (Silva Manso) Benth. and Hook. f. ex. S. Moore. Revista Árvore, vol. 30, no. 1, pp. 25-32. http://dx.doi.org/10.1590/S0100-67622006000100004.
http://dx.doi.org/10.1590/S0100-67622006... ). The chemical composition of seed reserves can influence germination, vigor, and storage potential (Bewley et al., 2013BEWLEY, J.D., BRADFORD, K.J., HILHORST, H.W.M. and NONOGAKI, H., 2013. Seeds: physiology of development, germination, and dormancy. 3rd ed. New York: Springer, 392 p. http://dx.doi.org/10.1007/978-1-4614-4693-4.
http://dx.doi.org/10.1007/978-1-4614-469... ). However, anatomical and histochemical studies of tropical seeds are still considered scarce (Barbosa et al., 2021BARBOSA, T.C.T., MENDONÇA, M.S., NASCIMENTO, L.L.A.M. and MORIM, M.P., 2021. Morphoanatomical and histochemical study of seeds of four species of Swartzia (Fabaceae - Papilionoideae) at Tupé Sustainable Development Reserve AM/Brazil. Botanical Sciences, vol. 99, no. 4, pp. 863-876. http://dx.doi.org/10.17129/botsci.2759.
http://dx.doi.org/10.17129/botsci.2759... ; Ferreira et al., 2020FERREIRA, C.D., SILVA-CARDOSO, I.M.D., FERREIRA, J.C.B., COSTA, F.H.S. and SCHERWINSKI-PEREIRA, J.E., 2020. Morphostructural and histochemical dynamics of Euterpe precatoria (Arecaceae) germination. Journal of Plant Research, vol. 133, no. 5, pp. 693-713. http://dx.doi.org/10.1007/s10265-020-01219-7. PMid:32767021.
http://dx.doi.org/10.1007/s10265-020-012... ; Ribeiro et al., 2021RIBEIRO, O.D., NASCIMENTO, W.M.O., CRUZ, F.J.R. and GURGEL, E.S.C., 2021. Seed anatomy and histochemistry of Myrciaria dubia (Kunth) McVaugh, an Amazonian Myrtaceace. Flora, vol. 280, p. 151847. http://dx.doi.org/10.1016/j.flora.2021.151847.
http://dx.doi.org/10.1016/j.flora.2021.1... ).

Given the ecological and economic importance of the representatives of the Bromeliaceae, studies with these approaches have been carried out on the seeds of some species of this family (Cecchi et al., 1996CECCHI, A.F., PALANDRI, M.R., FALCO, P. and TANI, G., 1996. Cytological aspects of the hypocotyl correlated to the behavior of the embryo radicle of Tillandsia atmospheric species. Caryologia, vol. 49, no. 2, pp. 113-124. http://dx.doi.org/10.1080/00087114.1996.10797356.
http://dx.doi.org/10.1080/00087114.1996.... ; Cecchifiordi et al., 2001CECCHIFIORDI, A., PALANDRI, M., TURICCHIA, S., GABRIELETANI and FALCO, P., 2001. Characterization of the seed reserves in Tillandsia (Bromeliaceae) and ultrastructural aspects of their use at germination. Caryologia, vol. 54, no. 1, pp. 1-16. http://dx.doi.org/10.1080/00087114.2001.10589208.
http://dx.doi.org/10.1080/00087114.2001.... ; Morra et al., 2002MORRA, L., DOTTORI, N. and COSA, M., 2002. Ontogenia y anatomía de semilla y fruto en Tillandsia tricholepis (Bromeliaceae). Boletín de la Sociedad Argentina de Botánica, vol. 37, pp. 193-201.; Palací et al., 2004PALACÍ, C., BROWN, G. and TUTHILL, D., 2004. The seeds of Catopsis (Bromeliaceae: tillandsioideae). Systematic Botany, vol. 29, no. 3, pp. 518-527. http://dx.doi.org/10.1600/0363644041744473.
http://dx.doi.org/10.1600/03636440417444... ; Magalhães and Mariath, 2012MAGALHÃES, R. and MARIATH, J., 2012. Seed morphoanatomy and its systematic relevance to Tillandsioideae (Bromeliaceae). Plant Systematics and Evolution, vol. 298, no. 10, pp. 1881-1895. http://dx.doi.org/10.1007/s00606-012-0688-3.
http://dx.doi.org/10.1007/s00606-012-068... ; Prado et al., 2014PRADO, J.P.C., SCHMIDT, E.C., STEINMACHER, D.A., GUERRA, M.P., BOUZON, Z.L., VESCO, L.L.D. and PESCADOR, R., 2014. Seed morphology of Vriesea friburgensis var. paludosa L.B. Sm. (Bromeliaceae). Hoehnea, vol. 41, no. 4, pp. 553-562. http://dx.doi.org/10.1590/2236-8906-08/2013.
http://dx.doi.org/10.1590/2236-8906-08/2... ; Chilpa-Galván et al., 2018CHILPA-GALVÁN, N., MÁRQUEZ-GUZMÁN, J., ZOTZ, G., ECHEVARRÍA-MACHADO, I., ANDRADE, J.L., ESPADAS-MANRIQUE, C. and REYES-GARCÍA, C., 2018. Seed traits favouring dispersal and establishment of six epiphytic Tillandsia (Bromeliaceae) species. Seed Science Research, vol. 28, no. 4, pp. 349-359. http://dx.doi.org/10.1017/S0960258518000247.
http://dx.doi.org/10.1017/S0960258518000... ; Mendes et al., 2018MENDES, S.P., VIEIRA, R.C. and TONI, K.L.G., 2018. Embryo and endosperm development in Pitcairnia encholirioides (Pitcairnioideae - Bromeliaceae): an endangered species of the Atlantic Forest. Flora, vol. 246-247, pp. 10-18. http://dx.doi.org/10.1016/j.flora.2018.06.006.
http://dx.doi.org/10.1016/j.flora.2018.0... , Silva et al., 2020aSILVA, K.R., STÜTZEL, T. and ORIANI, A., 2020a. Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits. Botanical Journal of the Linnean Society, vol. 192, no. 4, pp. 868-886. http://dx.doi.org/10.1093/botlinnean/boz111.
http://dx.doi.org/10.1093/botlinnean/boz... ; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ; Mendes et al., 2021MENDES, S.P., COSTA, C.G. and TONI, K.L.G., 2021. Endosperm development in Dyckia pseudococcinea (Pitcairnioideae - Bromeliaceae). Rodriguésia, vol. 72, p. e01682019. http://dx.doi.org/10.1590/2175-7860202172025.
http://dx.doi.org/10.1590/2175-786020217... ; Silva et al., 2021SILVA, S.S., SOUZA, H., SOUZA, F., MAX, D., ROSSI, M. and COSTA, M., 2021. Post-seminal development and cryopreservation of endemic or endangered bromeliads. Anais da Academia Brasileira de Ciências, vol. 93, no. 1, p. e20191133. http://dx.doi.org/10.1590/0001-3765202120191133. PMid:33909820.
http://dx.doi.org/10.1590/0001-376520212... ). However, for the species A. ananassoides, few studies have focused on these reproductive structures. Studies carried out with this species have evaluated aspects of floral biology (Stahl et al., 2012STAHL, J.M., NEPI, M., GALETTO, L., GUIMARÃES, E. and MACHADO, S.R., 2012. Functional aspects of floral nectar secretion of Ananas ananassoides, an ornithophilous bromeliad from the Brazilian savanna. Annals of Botany, vol. 109, no. 7, pp. 1243-1252. http://dx.doi.org/10.1093/aob/mcs053. PMid:22455992.
http://dx.doi.org/10.1093/aob/mcs053... ), the spatial distribution pattern (Elias et al., 2017ELIAS, F., TEIXEIRA, N. and MARIMON, B.H., 2017. Spatial relationships between Ananas ananassoides (Bromeliaceae) and Tachigali vulgaris (Fabaceae) influencing the structure of the Amazon/Cerrado transition in Brazil. Ecología Austral, vol. 27, no. 2, pp. 290-295. http://dx.doi.org/10.25260/EA.17.27.2.0.440.
http://dx.doi.org/10.25260/EA.17.27.2.0.... ), and the generation of new hybrids with ornamental purposes (Souza et al., 2009SOUZA, F.V.D., CABRAL, J.R.S., SOUZA, E.H., SILVA, M.J., SANTOS, O.S.N. and FERREIRA, F.R., 2009. Evaluation of F1 Hybrids between Ananas comosus var. ananassoides and Ananas comosus var. erectifolius. Acta Horticulturae, vol. 822, pp. 79-84. http://dx.doi.org/10.17660/ActaHortic.2009.822.8.
http://dx.doi.org/10.17660/ActaHortic.20... ). There are some studies on the seeds of this species, but these were focused on germination, investigating the effects of light, temperature and storage (Silveira et al., 2010SILVEIRA, F.A., SANTOS, J.C. and FERNANDES, G.W., 2010. Seed germination ecophysiology of the wild pineapple, Ananas ananassoides (Baker) L.B.Sm. (Bromeliaceae). Acta Botanica Brasílica, vol. 24, no. 4, pp. 1100-1103. http://dx.doi.org/10.1590/S0102-33062010000400026.
http://dx.doi.org/10.1590/S0102-33062010... ), and evaluating pre-germination treatments (Anastácio and Santana, 2010ANASTÁCIO, M.R. and SANTANA, D., 2010. Características germinativas de sementes de Ananas ananassoides (Baker) L.B.Sm. (Bromeliaceae). Acta Scientiarum. Biological Sciences, vol. 32, no. 2, pp. 195-200. http://dx.doi.org/10.4025/actascibiolsci.v32i2.1693.
http://dx.doi.org/10.4025/actascibiolsci... ). Other studies only used seeds to obtain material that would later be evaluated under different in vitro conditions (Silva et al., 2017SILVA, P.P., KURITA, F.M. and TAMAKI, V., 2017. In vitro propagation of Ananas comosus var. ananassoides (Baker) Coppens and F. Leal (Bromeliaceae). Científica, vol. 45, no. 3, pp. 313-320. http://dx.doi.org/10.15361/1984-5529.2017v45n3p313-320.
http://dx.doi.org/10.15361/1984-5529.201... ; Silva et al., 2020bSILVA, P.P.A., MEDINA, I.A., YOUNG, J.L.M. and TAMAKI, V., 2020b. Nitrogen assimilation in the bromeliad Ananas comosus var. ananassoides (Baker) Coppens and F. Leal grown in vitro with different sources of inorganic nitrogen. Hoehnea, vol. 47, p. e962019. http://dx.doi.org/10.1590/2236-8906-96/2019.
http://dx.doi.org/10.1590/2236-8906-96/2... ). Given the scarcity of detailed information about A. ananassoides seeds, the present work proposes to describe the morpho-anatomy and histochemistry of its seed. Results from this study will contribute to further investigations in the field of taxonomy, ecology, breeding systems, and propagation, among others. We also anticipate that our study will provide global knowledge for this species which has high potential for agricultural development in the tropic due to its ornamental features.

2. Material and Methods

2.1. Material collection and morphological characterization

Ripe fruits (n = 30) were collected from three natural populations in the sub-region Savannas in the municipality of Galeras (9°1’44”N and 74°58’19”W; 9°1’43”N and 74°58’22”W; 9°1’40”N and 74°58’20”W) Sucre, Colombia, with the altitudinal range varying from 29 to 35 m above sea level. The mean monthly annual temperature ranged from 28ºC, with an average annual precipitation of 1233 mm. The localities are characterized by presenting a continuous matrix of herbaceous vegetation and scattered small trees. Soils are poorly drained and remain flooded for several weeks. The localities are surrounded by bushy vegetation, and low pastures for cattle. Also, human intervention takes place in the area. Voucher specimens were deposited in the Herbarium HEUS, University of Sucre.

Length and width of the fruits were measured with a Vernier caliper. The pericarp was removed manually with a domestic knife to obtain the seeds. Subsequently, the number of seeds per fruit was counted and then these were described in terms of their shape, color and biometrics (seed width and length). The seeds were soaked in distilled water for 24 h and then cut with a steel razor blade. The seed portion occupied by the embryo is the mean value obtained by dividing the embryo length by the seed length (Magalhães and Mariath, 2012MAGALHÃES, R. and MARIATH, J., 2012. Seed morphoanatomy and its systematic relevance to Tillandsioideae (Bromeliaceae). Plant Systematics and Evolution, vol. 298, no. 10, pp. 1881-1895. http://dx.doi.org/10.1007/s00606-012-0688-3.
http://dx.doi.org/10.1007/s00606-012-068... ) analyzed with Image J software version 1.8.0 (National Institutes of Health, Bethesda, Maryland, USA).

2.2. Seed anatomy and histochemical characterization

Samples were fixed in FAA (formalin, acetic acid, 50% ethanol) (Johansen, 1940JOHANSEN, D., 1940. Plant microtechnique. New York: McGraw-Hill Books, 523 p.) and dehydrated in a graded ethanolic series. The material was embedded in histological paraffin (Johansen, 1940JOHANSEN, D., 1940. Plant microtechnique. New York: McGraw-Hill Books, 523 p.) and transversal and longitudinal sections (10 µm thick) were made with a rotary microtome (MRP 2015 Lupetec). For the anatomical evaluation the material was stained with 0.5% Toluidine Blue O, at pH 4.7 (O’Brien et al., 1964O’BRIEN, T., FEDER, N. and MCCULLY, M., 1964. Polychromatic staining of plant cell walls by toluidine blue O. Protoplasma, vol. 59, no. 2, pp. 368-373. http://dx.doi.org/10.1007/BF01248568.
http://dx.doi.org/10.1007/BF01248568... ). To verify the nature of the substances accumulated in the seeds, some histochemical tests were performed, such as Toluidine Blue O, Ferric Chloride solution, Ruthenium Red, Periodic Acid-Schiff, Coomassie Brilliant Blue and Lugol's reagent (Table 1). The permanents preparations were mounted in Canada balsam. Fresh material were also stained with Sudan III (Table 1). Photographs of the anatomical aspects of the seeds were taken with a digital camera coupled with a light microscope (Labomed Lx400). The terminology used for seed coat description follows Corner’s (Corner, 1976CORNER, E.J.H., 1976. The seeds of dicotyledons. Cambridge: Cambridge University Press, 320 p.) classification. Thus, the outer seed coat is called the testa, and the inner seed coat is the tegmen.

3. Results

3.1. Morphological characterization

Ananas ananassoides presented an ovoid-shaped fruit, yellow at maturity and with a leafy crown on top (Figure 1a). It was a multiple fruit formed by the fusion of small berry-like individual fruits. It had a hard rind formed by floral bracts, under which are perianth remains. Each of the flowers was subtended by a bract and the ovaries were inferior and trilocular (Figure 1a). When seeds were formed, they developed on the middle axis of the fruit.

Figure 1
Morphology of Ananas ananassoides: (a) Fruit and (b) seed. Scale bars: (a) = 1 cm; (b) =1 mm.

The multiple fruit presented an average of 4.34 small seeds (Table 2). The seed was rounded at one end, tapering towards the other. It was dark brown, with a mucilaginous envelope. The seed coat was tough and leathery with numerous ridges running along the length of the seed (Figure 1b).

3.2. Seed anatomy and histochemical characterization

In the evaluated material the seed coat, endosperm and embryo were differentiated (Figure 2a). Several cell layers made up the seed coat. These cells had thickened walls that contained phenolic compounds (lignin) and pectin inside, which gave the seed coat a brownish color (Figure 2b-2d, Table 1). They also positively reacted to Periodic Acid-Schiff, which detects polysaccharides (Figure 2e).

Figure 2
Ananas ananassoides seeds under light microscopy: (a-h) Longitudinal sections; (b-h) Detail of the integuments and endosperm; (i) Cross section of the endosperm; (j) Cross section of the embryo; (a) Positive reaction to Sudan III in integuments and embryo. The three basic components of seeds are identified: seed coat, endosperm and embryo. The embryo occupies less than 10% of the volume of the seed. (b). Positive reaction to Toluidine Blue O indicating presence of phenolic compounds and pectins in the integument (asterisk). Pronounced ridges in the integuments (arrow); (c) Positive reaction to ferric chloride indicating presence of phenolic compounds in the integument (asterisk) and aleurone layer (arrowhead); (d) Positive reaction to Ruthenium Red indicating the presence of pectins in cell walls. Testa with thickened walls (arrowhead); (e) Positive reaction to Periodic Acid-Schiff Neutral polysaccharides in the testa (asterisk) and starch grains in the endosperm (arrowhead); (f) Positive reaction to Coomassie Brilliant Blue. Aleurone layer with protein granules (arrowhead). Pronounced ridges in the integuments (arrow); (g) Positive reaction to Sudan III. Aleurone layer made up of several strata in the region around the embryo (arrowhead). Oil in the embryo (asterisk); (h) Negative reaction to Lugol’s reagent in aleurone layer (asterisk). Pronounced ridges in the integuments (arrow); (i) Positive reaction to Lugol's reagent in the endosperm. Starch grains (arrowhead); (j) Positive reaction to Coomassie Brilliant Blue in the embryo. Protein (arrowhead). al: aleurone layer; em: embryo; en: endotegmen; ep: endosperm; ex: exotegmen; sc: seed coat; te: testa. Scale bars: a = 500 μm; b-j = 100 μm.

The testa was made up of colorless cells with thickened walls (Figure 2d). A biseriate tegmen was identified, consisting of cells with reduced lumen, with thickened walls. The exotegmen was constituted by a palisade of lignified Malpighi cells while the endotegmen was collapsed. The cells of the two integuments (testa and tegmen) show pronounced ridges (Figure 2b, 2f and 2h).

The endosperm represented more than 90% of the seed (Figure 2a, Table 2). Surrounding the endosperm cells was a layer of smaller cells filled with protein granules (Figure 2f). This aleurone layer was made up of one to four cell strata. Generally, several strata were presented in the region around the embryo (Figure 2g). This layer was formed by cubic or irregular shape cells, with thick cell walls rich in polysaccharides, mainly pectins (Figure 2b-2d). Phenolic compounds, evidenced by the positive reaction (black color) to ferric chloride and lipid content evidenced by the positive reaction to Sudan III, were observed in the cellular cytoplasm (Figure 2c and 2g). Starch was not detected (Figure 2h). The endosperm was formed by larger irregular cells with thin walls and inconspicuous nuclei. The photomicrographs of the stained cross-sections showed numerous starch grains in the endosperm (Figure 2e and 2i).

The embryo is typically of a monocotyledonous. It was small, basal, undivided, homogeneous, and without apparent delimitations of its main structures. Likewise, it was slightly curved and more pointed at one end than the other. It occupied less than 10% of the volume of the seed and was located at its narrow end (Figure 2a). It is made up of isodiametric cells filled with oil and protein (Figure 2g and 2j).

4. Discussion

The morphology and anatomy of the fruits and seeds are relevant for the taxonomy of Bromeliaceae (Smith and Downs, 1974SMITH, L.B. and DOWNS, R.J., 1974. Flora Neotropica: Pitcairnioideae (Bromeliaceae). New York: Hafner Press, 658 p.; Fagundes and Mariath, 2014FAGUNDES, N.F. and MARIATH, J.E.A., 2014. Ovule ontogeny in Billbergia nutans in the evolutionary context of Bromeliaceae (Poales). Plant Systematics and Evolution, vol. 300, pp. 1323-1336. http://dx.doi.org/10.1007/s00606-013-0964-x.
http://dx.doi.org/10.1007/s00606-013-096... ; Magalhães and Mariath, 2012MAGALHÃES, R. and MARIATH, J., 2012. Seed morphoanatomy and its systematic relevance to Tillandsioideae (Bromeliaceae). Plant Systematics and Evolution, vol. 298, no. 10, pp. 1881-1895. http://dx.doi.org/10.1007/s00606-012-0688-3.
http://dx.doi.org/10.1007/s00606-012-068... ; Silva et al., 2020aSILVA, K.R., STÜTZEL, T. and ORIANI, A., 2020a. Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits. Botanical Journal of the Linnean Society, vol. 192, no. 4, pp. 868-886. http://dx.doi.org/10.1093/botlinnean/boz111.
http://dx.doi.org/10.1093/botlinnean/boz... ). Our morphological description is the same observed in several species of the Bromelioideae subfamily in which the seeds have a mucilaginous coat and the fruits are fleshy (Benzing, 2000BENZING, D.H., 2000. Bromeliaceae: profile of an adaptive radiation. New York: Cambridge University Press, 710 p. http://dx.doi.org/10.1017/CBO9780511565175.
http://dx.doi.org/10.1017/CBO97805115651... ; Pereira et al., 2008PEREIRA, A., PEREIRA, T., RODRIGUES, Â. and ANDRADE, Â., 2008. Morfologia de sementes e do desenvolvimento pós-seminal de espécies de Bromeliaceae. Acta Botanica Brasílica, vol. 22, no. 4, pp. 1150-1162. http://dx.doi.org/10.1590/S0102-33062008000400026.
http://dx.doi.org/10.1590/S0102-33062008... ; Silva and Scatena, 2011SILVA, I. and SCATENA, V., 2011. Morfologia de sementes e de estâdios iniciais de plântulas de espécies de Bromeliaceae de Amazônia. Rodriguésia, vol. 62, no. 2, pp. 263-272. http://dx.doi.org/10.1590/2175-7860201162204.
http://dx.doi.org/10.1590/2175-786020116... ; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ; Silva et al., 2020aSILVA, K.R., STÜTZEL, T. and ORIANI, A., 2020a. Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits. Botanical Journal of the Linnean Society, vol. 192, no. 4, pp. 868-886. http://dx.doi.org/10.1093/botlinnean/boz111.
http://dx.doi.org/10.1093/botlinnean/boz... ). According to Silva et al. (2020a)SILVA, K.R., STÜTZEL, T. and ORIANI, A., 2020a. Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits. Botanical Journal of the Linnean Society, vol. 192, no. 4, pp. 868-886. http://dx.doi.org/10.1093/botlinnean/boz111.
http://dx.doi.org/10.1093/botlinnean/boz... , the fleshiness of fruits is considered a synapomorphy of Bromelioideae.

Regarding the color of the seed coat, Bewley et al. (2013)BEWLEY, J.D., BRADFORD, K.J., HILHORST, H.W.M. and NONOGAKI, H., 2013. Seeds: physiology of development, germination, and dormancy. 3rd ed. New York: Springer, 392 p. http://dx.doi.org/10.1007/978-1-4614-4693-4.
http://dx.doi.org/10.1007/978-1-4614-469... indicates that it is a distinguishing feature of many seeds, but sometimes cannot be used taxonomically because they may change due to environmental and genetic influences during development. The reduced number of seeds per fruit found in A. ananassoides is related to the self-incompatibility present in most Ananas wild types (including A. ananassoides), and to sterility factors probably accumulated due to dominant vegetative reproduction (d’Eeckenbrugge et al., 1993D’EECKENBRUGGE, G.C., DUVAL, M.-F. and VAN MIEGROET, F., 1993. Fertility and self-incompatibility in the genus Ananas. Acta Horticulturae, vol. 334, pp. 45-52. http://dx.doi.org/10.17660/ActaHortic.1993.334.4.
http://dx.doi.org/10.17660/ActaHortic.19... ; Souza et al., 2017bSOUZA, E.H., VERSIEUX, L.M., SOUZA, F.V.D., ROSSI, M.L., COSTA, M.A.P.C. and MARTINELLI, A.P., 2017b. Interspecific and intergeneric hybridization in Bromeliaceae and their relationships to breeding systems. Scientia Horticulturae, vol. 223, pp. 53-61. http://dx.doi.org/10.1016/j.scienta.2017.04.027.
http://dx.doi.org/10.1016/j.scienta.2017... ).

We classified the seed coat strata of A. ananassoides, using as reference the ontogenetic analysis of the seeds of A. comosus (Rao and Wee, 1979RAO, A.N. and WEE, Y.C., 1979. Embryology of the Pineapple, Ananas comosus (L.) Merr. 1979. The New Phytologist, vol. 83, no. 2, pp. 485-497.) and other species (Aechmea bromeliifolia, Billbergia distachia and Neoregelia bahiana) of the Bromelioideae subfamily (Silva et al., 2020aSILVA, K.R., STÜTZEL, T. and ORIANI, A., 2020a. Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits. Botanical Journal of the Linnean Society, vol. 192, no. 4, pp. 868-886. http://dx.doi.org/10.1093/botlinnean/boz111.
http://dx.doi.org/10.1093/botlinnean/boz... ). Silva et al. (2020a)SILVA, K.R., STÜTZEL, T. and ORIANI, A., 2020a. Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits. Botanical Journal of the Linnean Society, vol. 192, no. 4, pp. 868-886. http://dx.doi.org/10.1093/botlinnean/boz111.
http://dx.doi.org/10.1093/botlinnean/boz... , indicated that there are different ontogenetic processes during seed development among bromeliad subfamilies. According to these authors, in Bromelioideae species, all cell layers of both outer and inner integuments are persistent, forming the seed coat, which is thus composed of testa and tegmen. We clearly identify these layers in A. ananassoides.

According to Crang et al. (2018)CRANG, R., LYONS-SOBASKI, S. and WISE, R., 2018. Plant anatomy: a concept-based approach to the structure of seed plants. Cham: Springer, 725 p. http://dx.doi.org/10.1007/978-3-319-77315-5.
http://dx.doi.org/10.1007/978-3-319-7731... during desiccation of seeds at the final stage of their ripening, the seed surface relief, acquires a characteristic pattern that is stable and taxon-specific. For example, the mucilaginous nature of the A. ananassoides seed is the result of the enlargement of the cells of the outer integument due to the accumulation of compounds, observed in later stages of seeds development in Bromelioideae species (Benzing, 2000BENZING, D.H., 2000. Bromeliaceae: profile of an adaptive radiation. New York: Cambridge University Press, 710 p. http://dx.doi.org/10.1017/CBO9780511565175.
http://dx.doi.org/10.1017/CBO97805115651... ; Silva et al., 2020aSILVA, K.R., STÜTZEL, T. and ORIANI, A., 2020a. Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits. Botanical Journal of the Linnean Society, vol. 192, no. 4, pp. 868-886. http://dx.doi.org/10.1093/botlinnean/boz111.
http://dx.doi.org/10.1093/botlinnean/boz... ). This mucilage possibly prevents desiccation, helps their fixation on appropriate places for germination, and is related to dispersal by animals (Pereira et al., 2008PEREIRA, A., PEREIRA, T., RODRIGUES, Â. and ANDRADE, Â., 2008. Morfologia de sementes e do desenvolvimento pós-seminal de espécies de Bromeliaceae. Acta Botanica Brasílica, vol. 22, no. 4, pp. 1150-1162. http://dx.doi.org/10.1590/S0102-33062008000400026.
http://dx.doi.org/10.1590/S0102-33062008... ; Silva and Scatena, 2011SILVA, I. and SCATENA, V., 2011. Morfologia de sementes e de estâdios iniciais de plântulas de espécies de Bromeliaceae de Amazônia. Rodriguésia, vol. 62, no. 2, pp. 263-272. http://dx.doi.org/10.1590/2175-7860201162204.
http://dx.doi.org/10.1590/2175-786020116... ; Silva et al., 2020aSILVA, K.R., STÜTZEL, T. and ORIANI, A., 2020a. Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits. Botanical Journal of the Linnean Society, vol. 192, no. 4, pp. 868-886. http://dx.doi.org/10.1093/botlinnean/boz111.
http://dx.doi.org/10.1093/botlinnean/boz... ).

A. ananassoides seeds proved to be similar in size and shape to other species of the Bromelioideae genera: Ananas, Aechmea, Billbergia, Neoregelia and Bromelia (Pereira et al., 2008PEREIRA, A., PEREIRA, T., RODRIGUES, Â. and ANDRADE, Â., 2008. Morfologia de sementes e do desenvolvimento pós-seminal de espécies de Bromeliaceae. Acta Botanica Brasílica, vol. 22, no. 4, pp. 1150-1162. http://dx.doi.org/10.1590/S0102-33062008000400026.
http://dx.doi.org/10.1590/S0102-33062008... ; Silva and Scatena, 2011SILVA, I. and SCATENA, V., 2011. Morfologia de sementes e de estâdios iniciais de plântulas de espécies de Bromeliaceae de Amazônia. Rodriguésia, vol. 62, no. 2, pp. 263-272. http://dx.doi.org/10.1590/2175-7860201162204.
http://dx.doi.org/10.1590/2175-786020116... ; Silva et al., 2020aSILVA, K.R., STÜTZEL, T. and ORIANI, A., 2020a. Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits. Botanical Journal of the Linnean Society, vol. 192, no. 4, pp. 868-886. http://dx.doi.org/10.1093/botlinnean/boz111.
http://dx.doi.org/10.1093/botlinnean/boz... ; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ). However, anatomical analyzes indicate that in the seed of A. ananassoides, there is a palisade of lignified Malpighi cells, which constitute the exotegmen. This has previously been reported for the genus Ananas and Bromelia (Rao and Wee, 1979RAO, A.N. and WEE, Y.C., 1979. Embryology of the Pineapple, Ananas comosus (L.) Merr. 1979. The New Phytologist, vol. 83, no. 2, pp. 485-497.; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ). In addition, A. ananassoides, as well as in A. comosus, present ridges in the two integuments (testa and tegmen) that have not been anatomically evidenced in other genera of bromeliads (Rao and Wee, 1979RAO, A.N. and WEE, Y.C., 1979. Embryology of the Pineapple, Ananas comosus (L.) Merr. 1979. The New Phytologist, vol. 83, no. 2, pp. 485-497.; Prado et al., 2014PRADO, J.P.C., SCHMIDT, E.C., STEINMACHER, D.A., GUERRA, M.P., BOUZON, Z.L., VESCO, L.L.D. and PESCADOR, R., 2014. Seed morphology of Vriesea friburgensis var. paludosa L.B. Sm. (Bromeliaceae). Hoehnea, vol. 41, no. 4, pp. 553-562. http://dx.doi.org/10.1590/2236-8906-08/2013.
http://dx.doi.org/10.1590/2236-8906-08/2... , Magalhães and Mariath, 2012MAGALHÃES, R. and MARIATH, J., 2012. Seed morphoanatomy and its systematic relevance to Tillandsioideae (Bromeliaceae). Plant Systematics and Evolution, vol. 298, no. 10, pp. 1881-1895. http://dx.doi.org/10.1007/s00606-012-0688-3.
http://dx.doi.org/10.1007/s00606-012-068... ; Chilpa-Galván et al., 2018CHILPA-GALVÁN, N., MÁRQUEZ-GUZMÁN, J., ZOTZ, G., ECHEVARRÍA-MACHADO, I., ANDRADE, J.L., ESPADAS-MANRIQUE, C. and REYES-GARCÍA, C., 2018. Seed traits favouring dispersal and establishment of six epiphytic Tillandsia (Bromeliaceae) species. Seed Science Research, vol. 28, no. 4, pp. 349-359. http://dx.doi.org/10.1017/S0960258518000247.
http://dx.doi.org/10.1017/S0960258518000... ; Silva et al., 2020aSILVA, K.R., STÜTZEL, T. and ORIANI, A., 2020a. Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits. Botanical Journal of the Linnean Society, vol. 192, no. 4, pp. 868-886. http://dx.doi.org/10.1093/botlinnean/boz111.
http://dx.doi.org/10.1093/botlinnean/boz... ; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ). We observed that the ridges in the endotegmen of A. ananassoides are more pronounced than in A. comosus. On the other hand, several studies have reported the presence of polysaccharides and phenolic compounds in the seed coat of bromeliad (Prado et al., 2014PRADO, J.P.C., SCHMIDT, E.C., STEINMACHER, D.A., GUERRA, M.P., BOUZON, Z.L., VESCO, L.L.D. and PESCADOR, R., 2014. Seed morphology of Vriesea friburgensis var. paludosa L.B. Sm. (Bromeliaceae). Hoehnea, vol. 41, no. 4, pp. 553-562. http://dx.doi.org/10.1590/2236-8906-08/2013.
http://dx.doi.org/10.1590/2236-8906-08/2... ; Magalhães and Mariath, 2012MAGALHÃES, R. and MARIATH, J., 2012. Seed morphoanatomy and its systematic relevance to Tillandsioideae (Bromeliaceae). Plant Systematics and Evolution, vol. 298, no. 10, pp. 1881-1895. http://dx.doi.org/10.1007/s00606-012-0688-3.
http://dx.doi.org/10.1007/s00606-012-068... ; Chilpa-Galván et al., 2018CHILPA-GALVÁN, N., MÁRQUEZ-GUZMÁN, J., ZOTZ, G., ECHEVARRÍA-MACHADO, I., ANDRADE, J.L., ESPADAS-MANRIQUE, C. and REYES-GARCÍA, C., 2018. Seed traits favouring dispersal and establishment of six epiphytic Tillandsia (Bromeliaceae) species. Seed Science Research, vol. 28, no. 4, pp. 349-359. http://dx.doi.org/10.1017/S0960258518000247.
http://dx.doi.org/10.1017/S0960258518000... ; Silva et al., 2020aSILVA, K.R., STÜTZEL, T. and ORIANI, A., 2020a. Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits. Botanical Journal of the Linnean Society, vol. 192, no. 4, pp. 868-886. http://dx.doi.org/10.1093/botlinnean/boz111.
http://dx.doi.org/10.1093/botlinnean/boz... ; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ).

According to the presence of endosperm, A. ananassoides seed is classified as albuminous. However, the space occupied by the endosperm in bromeliads varies according to the genus. In Ananas and Bromelia genera, it has been reported that the endosperm occupies more than 90% of the seed (Rao and Wee, 1979RAO, A.N. and WEE, Y.C., 1979. Embryology of the Pineapple, Ananas comosus (L.) Merr. 1979. The New Phytologist, vol. 83, no. 2, pp. 485-497.; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ), in Vriesea occupies about 70% (Magalhães and Mariath, 2012MAGALHÃES, R. and MARIATH, J., 2012. Seed morphoanatomy and its systematic relevance to Tillandsioideae (Bromeliaceae). Plant Systematics and Evolution, vol. 298, no. 10, pp. 1881-1895. http://dx.doi.org/10.1007/s00606-012-0688-3.
http://dx.doi.org/10.1007/s00606-012-068... ; Prado et al., 2014PRADO, J.P.C., SCHMIDT, E.C., STEINMACHER, D.A., GUERRA, M.P., BOUZON, Z.L., VESCO, L.L.D. and PESCADOR, R., 2014. Seed morphology of Vriesea friburgensis var. paludosa L.B. Sm. (Bromeliaceae). Hoehnea, vol. 41, no. 4, pp. 553-562. http://dx.doi.org/10.1590/2236-8906-08/2013.
http://dx.doi.org/10.1590/2236-8906-08/2... ), and in Tillandsia it may occupy up to 60% of the seed interior or be completely consumed (Magalhães and Mariath, 2012MAGALHÃES, R. and MARIATH, J., 2012. Seed morphoanatomy and its systematic relevance to Tillandsioideae (Bromeliaceae). Plant Systematics and Evolution, vol. 298, no. 10, pp. 1881-1895. http://dx.doi.org/10.1007/s00606-012-0688-3.
http://dx.doi.org/10.1007/s00606-012-068... ; Chilpa-Galván et al., 2018CHILPA-GALVÁN, N., MÁRQUEZ-GUZMÁN, J., ZOTZ, G., ECHEVARRÍA-MACHADO, I., ANDRADE, J.L., ESPADAS-MANRIQUE, C. and REYES-GARCÍA, C., 2018. Seed traits favouring dispersal and establishment of six epiphytic Tillandsia (Bromeliaceae) species. Seed Science Research, vol. 28, no. 4, pp. 349-359. http://dx.doi.org/10.1017/S0960258518000247.
http://dx.doi.org/10.1017/S0960258518000... ; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ).

In the cereals, the majority of cells in the endosperm accumulate reserves inside and are nonliving at maturity. But on the outside of the endosperm remains a living tissue, the aleurone layer, which is responsible for the production and release of enzymes for the mobilization of these reserves (Bewley et al., 2013BEWLEY, J.D., BRADFORD, K.J., HILHORST, H.W.M. and NONOGAKI, H., 2013. Seeds: physiology of development, germination, and dormancy. 3rd ed. New York: Springer, 392 p. http://dx.doi.org/10.1007/978-1-4614-4693-4.
http://dx.doi.org/10.1007/978-1-4614-469... ). The distinction of an aleurone layer was recorded in Ananas comosus by Rao and Wee (1979)RAO, A.N. and WEE, Y.C., 1979. Embryology of the Pineapple, Ananas comosus (L.) Merr. 1979. The New Phytologist, vol. 83, no. 2, pp. 485-497.. These authors showed that this aleurone layer is one cell thick except for the region around the embryo, like what we observe in A. ananassoides. In Bromelia genus, an aleurone layer made up of three cell strata has also been observed, but these can appear surrounding the embryo or the rest of the endosperm (Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ). Studies with others genera of bromeliads also indicated the presence of this layer, which can appear made up only of a cell stratum (Cecchifiordi et al., 2001CECCHIFIORDI, A., PALANDRI, M., TURICCHIA, S., GABRIELETANI and FALCO, P., 2001. Characterization of the seed reserves in Tillandsia (Bromeliaceae) and ultrastructural aspects of their use at germination. Caryologia, vol. 54, no. 1, pp. 1-16. http://dx.doi.org/10.1080/00087114.2001.10589208.
http://dx.doi.org/10.1080/00087114.2001.... ; Palací et al., 2004PALACÍ, C., BROWN, G. and TUTHILL, D., 2004. The seeds of Catopsis (Bromeliaceae: tillandsioideae). Systematic Botany, vol. 29, no. 3, pp. 518-527. http://dx.doi.org/10.1600/0363644041744473.
http://dx.doi.org/10.1600/03636440417444... ; Prado et al., 2014PRADO, J.P.C., SCHMIDT, E.C., STEINMACHER, D.A., GUERRA, M.P., BOUZON, Z.L., VESCO, L.L.D. and PESCADOR, R., 2014. Seed morphology of Vriesea friburgensis var. paludosa L.B. Sm. (Bromeliaceae). Hoehnea, vol. 41, no. 4, pp. 553-562. http://dx.doi.org/10.1590/2236-8906-08/2013.
http://dx.doi.org/10.1590/2236-8906-08/2... ; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ). Magalhães and Mariath (2012)MAGALHÃES, R. and MARIATH, J., 2012. Seed morphoanatomy and its systematic relevance to Tillandsioideae (Bromeliaceae). Plant Systematics and Evolution, vol. 298, no. 10, pp. 1881-1895. http://dx.doi.org/10.1007/s00606-012-0688-3.
http://dx.doi.org/10.1007/s00606-012-068... , suggested that the presence/absence of the aleurone layer in the region in contact with the embryo provides an anatomical character that can help distinguish Vriesea and Tillandsia genera.

Similar to A. ananassoides, other species of bromeliads also have proteins and lipids in the aleurone layer and a high concentration of starch grains in the other cells of the endosperm (Cecchifiordi et al., 2001CECCHIFIORDI, A., PALANDRI, M., TURICCHIA, S., GABRIELETANI and FALCO, P., 2001. Characterization of the seed reserves in Tillandsia (Bromeliaceae) and ultrastructural aspects of their use at germination. Caryologia, vol. 54, no. 1, pp. 1-16. http://dx.doi.org/10.1080/00087114.2001.10589208.
http://dx.doi.org/10.1080/00087114.2001.... ; Palací et al., 2004PALACÍ, C., BROWN, G. and TUTHILL, D., 2004. The seeds of Catopsis (Bromeliaceae: tillandsioideae). Systematic Botany, vol. 29, no. 3, pp. 518-527. http://dx.doi.org/10.1600/0363644041744473.
http://dx.doi.org/10.1600/03636440417444... ; Scatena et al., 2006SCATENA, V., SEGECIN, S. and COAN, A., 2006. Seed morphology and post-seminal development of Tillandsia L. (Bromeliaceae) from the “Campos Gerais”, Paraná, southern Brazil. Brazilian Archives of Biology and Technology, vol. 49, no. 6, pp. 945-951. http://dx.doi.org/10.1590/S1516-89132006000700012.
http://dx.doi.org/10.1590/S1516-89132006... ; Magalhães and Mariath, 2012MAGALHÃES, R. and MARIATH, J., 2012. Seed morphoanatomy and its systematic relevance to Tillandsioideae (Bromeliaceae). Plant Systematics and Evolution, vol. 298, no. 10, pp. 1881-1895. http://dx.doi.org/10.1007/s00606-012-0688-3.
http://dx.doi.org/10.1007/s00606-012-068... ; Prado et al., 2014PRADO, J.P.C., SCHMIDT, E.C., STEINMACHER, D.A., GUERRA, M.P., BOUZON, Z.L., VESCO, L.L.D. and PESCADOR, R., 2014. Seed morphology of Vriesea friburgensis var. paludosa L.B. Sm. (Bromeliaceae). Hoehnea, vol. 41, no. 4, pp. 553-562. http://dx.doi.org/10.1590/2236-8906-08/2013.
http://dx.doi.org/10.1590/2236-8906-08/2... ; Chilpa-Galván et al., 2018CHILPA-GALVÁN, N., MÁRQUEZ-GUZMÁN, J., ZOTZ, G., ECHEVARRÍA-MACHADO, I., ANDRADE, J.L., ESPADAS-MANRIQUE, C. and REYES-GARCÍA, C., 2018. Seed traits favouring dispersal and establishment of six epiphytic Tillandsia (Bromeliaceae) species. Seed Science Research, vol. 28, no. 4, pp. 349-359. http://dx.doi.org/10.1017/S0960258518000247.
http://dx.doi.org/10.1017/S0960258518000... ; Mendes et al., 2021MENDES, S.P., COSTA, C.G. and TONI, K.L.G., 2021. Endosperm development in Dyckia pseudococcinea (Pitcairnioideae - Bromeliaceae). Rodriguésia, vol. 72, p. e01682019. http://dx.doi.org/10.1590/2175-7860202172025.
http://dx.doi.org/10.1590/2175-786020217... ; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ). However, the type of reserves accumulated in the endosperm of bromeliads may vary according to the species (Magalhães and Mariath, 2012MAGALHÃES, R. and MARIATH, J., 2012. Seed morphoanatomy and its systematic relevance to Tillandsioideae (Bromeliaceae). Plant Systematics and Evolution, vol. 298, no. 10, pp. 1881-1895. http://dx.doi.org/10.1007/s00606-012-0688-3.
http://dx.doi.org/10.1007/s00606-012-068... ; Chilpa-Galván et al., 2018CHILPA-GALVÁN, N., MÁRQUEZ-GUZMÁN, J., ZOTZ, G., ECHEVARRÍA-MACHADO, I., ANDRADE, J.L., ESPADAS-MANRIQUE, C. and REYES-GARCÍA, C., 2018. Seed traits favouring dispersal and establishment of six epiphytic Tillandsia (Bromeliaceae) species. Seed Science Research, vol. 28, no. 4, pp. 349-359. http://dx.doi.org/10.1017/S0960258518000247.
http://dx.doi.org/10.1017/S0960258518000... ; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ). Cecchifiordi et al. (2001)CECCHIFIORDI, A., PALANDRI, M., TURICCHIA, S., GABRIELETANI and FALCO, P., 2001. Characterization of the seed reserves in Tillandsia (Bromeliaceae) and ultrastructural aspects of their use at germination. Caryologia, vol. 54, no. 1, pp. 1-16. http://dx.doi.org/10.1080/00087114.2001.10589208.
http://dx.doi.org/10.1080/00087114.2001.... also reported that, in addition to starch, the endosperm in Tillandsia seeds also contains calcium oxalate. However, such oxalate crystals were not seen in A. ananassoides. On the other hand, in A. comosus,Rao and Wee (1979)RAO, A.N. and WEE, Y.C., 1979. Embryology of the Pineapple, Ananas comosus (L.) Merr. 1979. The New Phytologist, vol. 83, no. 2, pp. 485-497. stated that running through the center of the endosperm is a longitudinal dark groove resulting from the partly collapsed endosperm cells. In A. ananassoides this groove was not identified in the endosperm. According to Mendes et al. (2021)MENDES, S.P., COSTA, C.G. and TONI, K.L.G., 2021. Endosperm development in Dyckia pseudococcinea (Pitcairnioideae - Bromeliaceae). Rodriguésia, vol. 72, p. e01682019. http://dx.doi.org/10.1590/2175-7860202172025.
http://dx.doi.org/10.1590/2175-786020217... the Bromeliaceae family presents the helobial type of endosperm, which is a synapomorphy for the group.

The homogeneous and undivided embryo found in A. anannassoides, contrasts with embryos with advanced stage of development found in other bromeliad species (Magalhães and Mariath, 2012MAGALHÃES, R. and MARIATH, J., 2012. Seed morphoanatomy and its systematic relevance to Tillandsioideae (Bromeliaceae). Plant Systematics and Evolution, vol. 298, no. 10, pp. 1881-1895. http://dx.doi.org/10.1007/s00606-012-0688-3.
http://dx.doi.org/10.1007/s00606-012-068... ; Martelo-Solorzano et al., 2022MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... ). The A. ananasoides embryo shows a high concentration of protein and lipid, similar to that described for A. comosus seeds, but unlike this species, the procambium was not evidenced in A. ananasoides (Rao and Wee, 1979RAO, A.N. and WEE, Y.C., 1979. Embryology of the Pineapple, Ananas comosus (L.) Merr. 1979. The New Phytologist, vol. 83, no. 2, pp. 485-497.). Marcos-Filho (2005)MARCOS-FILHO, J., 2005. Fisiologia de sementes de plantas cultivadas. Piracicaba: FEALQ, 495 p., indicates that seeds with a large amount of starch have high storage potential. However, the abundant presence of lipids and proteins in the embryo, as recorded in A. ananassoides can reduce the storage time potential, due to the lower chemical stability of the lipids in relation to starch and the high affinity of the proteins with water. According to d’Eeckenbrugge et al. (2011)D’EECKENBRUGGE, G.C., SANEWSKI, G.M., SMITH, M.K., DUVAL, M.F. and LEAL, F., 2011. Ananas. In: C. KOLE, ed. Wild crop relatives: genomic and breeding resources-tropical and subtropical fruits. Berlin: Springer, pp. 21-41. http://dx.doi.org/10.1007/978-3-642-20447-0_2.
http://dx.doi.org/10.1007/978-3-642-2044... Ananas seeds can maintain viability for 2 years or more in dry and cool conditions, opening the possibility of a pineapple seedbank, provided that procedures can be optimized. These authors indicate that seed conservation techniques would be particularly interesting for wild germplasm. It should be noted that the chemical composition of seeds is ultimately determined by genetic factors and hence varies widely among species and their varieties and cultivars. Some modifications of composition may be imposed by environmental conditions prevalent during seed development and maturation, but such changes are usually minor (Bewley et al., 2013BEWLEY, J.D., BRADFORD, K.J., HILHORST, H.W.M. and NONOGAKI, H., 2013. Seeds: physiology of development, germination, and dormancy. 3rd ed. New York: Springer, 392 p. http://dx.doi.org/10.1007/978-1-4614-4693-4.
http://dx.doi.org/10.1007/978-1-4614-469... ).

Previous studies on A. ananassoides revealed high percentages (>90%) of germination and viability of seeds. However, germination was slow, taking up to more than three weeks and spreading over time (Anastácio and Santana, 2010ANASTÁCIO, M.R. and SANTANA, D., 2010. Características germinativas de sementes de Ananas ananassoides (Baker) L.B.Sm. (Bromeliaceae). Acta Scientiarum. Biological Sciences, vol. 32, no. 2, pp. 195-200. http://dx.doi.org/10.4025/actascibiolsci.v32i2.1693.
http://dx.doi.org/10.4025/actascibiolsci... ; Silveira et al., 2010SILVEIRA, F.A., SANTOS, J.C. and FERNANDES, G.W., 2010. Seed germination ecophysiology of the wild pineapple, Ananas ananassoides (Baker) L.B.Sm. (Bromeliaceae). Acta Botanica Brasílica, vol. 24, no. 4, pp. 1100-1103. http://dx.doi.org/10.1590/S0102-33062010000400026.
http://dx.doi.org/10.1590/S0102-33062010... ). Anastácio and Santana (2010)ANASTÁCIO, M.R. and SANTANA, D., 2010. Características germinativas de sementes de Ananas ananassoides (Baker) L.B.Sm. (Bromeliaceae). Acta Scientiarum. Biological Sciences, vol. 32, no. 2, pp. 195-200. http://dx.doi.org/10.4025/actascibiolsci.v32i2.1693.
http://dx.doi.org/10.4025/actascibiolsci... , found differences in the percentage of germination between newly collected and stored seeds, suggesting the presence of immature embryos in this species. According to Amaral et al. (2020)AMARAL, E.V.E.J., SALES, J.F., ZUCHI, J., NEVES, J.M.G. and OLIVEIRA, J.A., 2020. Analysis of radiographic images and germination of Campomanesia pubescens (Mart. ex DC.) O.Berg (Myrtaceae Juss.) seeds under drying. Brazilian Journal of Biology = Revista Brasileira de Biologia, vol. 80, no. 4, pp. 777-782. http://dx.doi.org/10.1590/1519-6984.219950. PMid:31778483.
http://dx.doi.org/10.1590/1519-6984.2199... , the presence of embryos with these characteristics is related to the low performance of the seeds in germination. Our observations confirm the poor development of the A. ananasoides embryo in ripe fruits, indicating a morphological dormancy. In addition, although the integument can provide physical dormancy (Molina-Guerra et al., 2020MOLINA-GUERRA, V., SOTO-MATA, B., ALANÍS-RODRÍGUEZ, E., JURADO, E., CUÉLLAR-RODRÍGUEZ, G., PANDO-MORENO, M. and ALCALÁ-ROJAS, A., 2020. Germination of Amoreuxia wrightii species at risk of extinction in Northeastern Mexico. Brazilian Journal of Biology = Revista Brasileira de Biologia, vol. 80, no. 2, pp. 485-486. http://dx.doi.org/10.1590/1519-6984.215807. PMid:31291409.
http://dx.doi.org/10.1590/1519-6984.2158... ), Anastácio and Santana (2010)ANASTÁCIO, M.R. and SANTANA, D., 2010. Características germinativas de sementes de Ananas ananassoides (Baker) L.B.Sm. (Bromeliaceae). Acta Scientiarum. Biological Sciences, vol. 32, no. 2, pp. 195-200. http://dx.doi.org/10.4025/actascibiolsci.v32i2.1693.
http://dx.doi.org/10.4025/actascibiolsci... , indicate that the integument of A. ananassoides is permeable and therefore the seeds do not have tegumentary dormancy. Nevertheless, the seed coat may contain chemical inhibitors, such as phenolic compounds that prevent embryonic growth (chemical dormancy) (Bewley et al., 2013BEWLEY, J.D., BRADFORD, K.J., HILHORST, H.W.M. and NONOGAKI, H., 2013. Seeds: physiology of development, germination, and dormancy. 3rd ed. New York: Springer, 392 p. http://dx.doi.org/10.1007/978-1-4614-4693-4.
http://dx.doi.org/10.1007/978-1-4614-469... ). We identify these compounds in the seed coat and the aleurone layer of A. ananassoides. This layer presents several strata in the region around the embryo, which potentially contributes to the growth inhibitory effect. In species of the genus Bromelia, Martelo-Solorzano et al. (2022)MARTELO-SOLORZANO, A.M., LIDUEÑA-PÉREZ, K.I. and CORREDOR-PRADO, J., 2022. Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest. Rodriguésia, vol. 73, p. e02122020. http://dx.doi.org/10.1590/2175-7860202273050.
http://dx.doi.org/10.1590/2175-786020227... related the high accumulation of phenols in the tegument with the longer time necessary for the seeds to germinate. Besides, it has been reported that some bromeliads of Tillandsia genus that do not accumulate reserves in the endosperm, germinate faster and require a shorter time to the seedling establishment than species with a copious endosperm (Montes-Recinas et al., 2012MONTES-RECINAS, S., MÁRQUEZ-GUZMÁN, J. and OROZCO-SEGOVIA, A., 2012. Temperature and water requirements for germination and effects of discontinuous hydration on germinated seed survival in Tillandsia recurvata L. Plant Ecology, vol. 213, no. 7, pp. 1069-1079. http://dx.doi.org/10.1007/s11258-012-0066-9.
http://dx.doi.org/10.1007/s11258-012-006... ).

To our knowledge, this is the first study that documents the morpho-anatomy and seed histochemistry of A. ananassoides. The richness of information that seeds can provide is highlighted, since the characters described in this work present information relevant to the taxonomy and physiology of the studied species. Our results provide anatomical characteristics that may contribute to distinguishing this species. Among them are: cell arrangement in the seed coat; ripples in the integument; the ratio of embryo size and endosperm amount and the number of strata in the aleurone layer. On the other hand, carbohydrates in the form of starch in the endosperm, and lipids and proteins in the embryo, constitute the seed's main nutritional reserves. The homogeneous embryo and phenolic compounds present in the seed coat and in the aleurone layer possibly contribute to the dormancy in this species. Lastly, we recommend conducting ontogenetic studies of A. ananassoides to better understand the origin of each seed coat layer.

Acknowledgements

We acknowledge financial support from the Departamento de Investigación de la Universidad de Sucre (DIUS).

References

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