Resumen Introducción: Cattleya crispa es una orquídea epífita ornamental con distribución geográfica restringida a la Mata Atlántica brasileña. Debido al extractivismo depredador y a la pérdida de hábitat inducida por el hombre, esta especie aparece en la Lista Roja de la Flora Brasileña. Objetivo: Caracterizar aspectos morfoanatómicos de la germinación y desarrollo inicial de semillas de C. crispa; así como estudiar el efecto de la criopreservación de estas semillas. Métodos: Utilizamos microscopía óptica, microscopía electrónica de barrido y microscopía electrónica de transmisión para describir la microestructura en 100 semillas maduras. Evaluamos la viabilidad de la semilla, la germinación de la semilla, la tasa de supervivencia y el peso de los protocormos en el material criopreservado y no criopreservado, con cuatro réplicas por tratamiento de 20 mg de material vegetal. Resultados: Las semillas son fusiformes, amarillo blanquecinas, con una longitud de 700 a 900 µm y un contenido de agua del 5 %. La germinación comenzó siete días después de la siembra, la formación del protocormo globular a los 30 días y la formación de la plántula a los 150 días. La cubierta de semilla persistente puede comprimir el protocormo y provocar su colapso. Las semillas criopreservadas presentaron 87.15 % de viabilidad, 78.32 % de germinación, 8.48 % de supervivencia y protocormos con 104.27 mg a los cinco meses de la siembra. Los datos no fueron diferentes a las semillas no criopreservadas. Conclusiones: La capacidad criogénica de las semillas muestra que la crioconservación puede utilizarse para la conservación a largo plazo. Los resultados de este trabajo contribuyen a la biología general de C. crispa y a la propagación y almacenamiento de material genético con fines de conservación.

Abstract Introduction: Cattleya crispa is an ornamental epiphytic orchid with geographic distribution restricted to the Brazilian Atlantic Forest. Due to predatory extractivism and human-induced habitat loss, this species appears on the Red List of Brazilian Flora. Objective: To characterize morpho-anatomical aspects regarding germination and post-seminal development from C. crispa seeds; as well as studying the effect of cryopreservation on these seeds. Methods: We used light microscopy and electron microscopy to describe the microstructure of a 100 ripe seeds. We evaluated seed viability, seed germination, survival rate and protocorm weight in cryopreserved and non-cryopreserved material, with four replicas per treatment using 20 mg of plant material. Results: The seeds are fusiform, whitish yellow with a length from 700 to 900 µm and a water content of 5 %. Germination began seven days after sowing, the formation of the globular protocorm at 30 days and the formation of the seedling occurred 150 days. The persistent seed coat can compress the protocorm and cause it to collapse. The cryopreserved seeds presented 87.15 % viability, 78.32 % germination, 8.48 % survival and protocorms with 104.27 mg five months after sowing. Data wasn't different to non-cryopreserved seeds. Conclusions: The cryocapability of the seeds shows that cryopreservation can be used for long-term conservation. The results of this work contribute to the overall biology of C. crispa and to the propagation and storage of genetic material for conservation purposes.

Resumo Drásticas transformações na floresta tropical seca levam à perda de seus componentes biológicos e revelam a importância dos estudos sobre a biologia das espécies que a habitam. Nosso objetivo foi descrever a morfoanatomia e a germinação das sementes, e o desenvolvimento pós-seminal de espécies de Bromeliaceae presentes em fragmentos de floresta seca em Sucre, Colombia. Foram avaliadas sete espécies que representam os gêneros Bromelia e Tillandsia. Os resultados fornecem características que estão relacionadas ao habitat de cada espécie e ajudam a distinguir os gêneros avaliados: medidas dos frutos e sementes, forma da semente, apêndices plumosos, particularidades da testa e da camada de aleurona, proporção do embrião e do endosperma, tipos de reservas, zona de constrição no embrião e tipo de desenvolvimento pós-seminal. As características dos apêndices plumosos e a presença de feixes vasculares no embrião contribuem para a distinção entre as espécies de Tillandsia. Nas espécies T. elongata e T. flexuosa, o grande número de sementes por fruto (> 100), seus aspectos morfoanatômicos, as altas porcentagens de germinação (> 92%) e formação de plântulas (> 77%), e o maiores valores do índice de velocidade de germinação (> 4,5) conferem-lhes a capacidade potencial de aumentar a área de distribuição neste ambiente. Nossos resultados proporcionam informações com relevância taxonômica e ecológica para as bromélias que habitam a floresta tropical seca.

Abstract Drastic changes in dry tropical forest result in the loss of biological components and reveal the importance of studies on the biology of species living in it. The present study aimed to describe seed morphoanatomy, germination and post-seminal development of Bromeliaceae species in fragments of tropical dry forest in Sucre, Colombia. Seven species representing Bromelia and Tillandsia genera were evaluated. The results provide characteristics related to the habitat of each species and contribute to distinguish the genera evaluated: fruit and seed measurements, seed shape, plumose appendage, testa characteristics, and the aleurone layer, embryo endosperm ratio, types of reserves, constriction zone in the embryo and type of post-seminal development. Characteristics of plumose appendages and the presence of vascular bundles in the embryo also contribute to distinguish Tillandsia species. In T. elongata and T. flexuosa, high number of seeds per fruit (> 100), morphoanatomical aspects, high germination (> 92%) and plant formation (> 77%) percentages, and higher germination rate values (> 4.5) give them the potential capacity for establishment in this environment. Our results provide information with taxonomic and ecological relevance for bromeliads in dry tropical forest.

ABSTRACT. Tissue culture techniques have been employed for bromeliad mass propagation by means of the morphogenetic route of nodular cluster cultures (NCs). This study aimed to assess protein, carbohydrate and global DNA methylation (GDM) level dynamics during NCs induction from Vriesea reitzii seeds. Seeds were inoculated into Murashige and Skoog (MS) liquid medium supplemented with 4 µM α-naphthaleneacetic acid (NAA) to induce NCs and in culture medium without plant growth regulators to form normal seedlings. Samples collected at 0, 3, 7, 10, 14, and 21 days of culture were analyzed. All parameters assessed showed the same variation pattern. However, seeds inducing NCs showed significantly lower starch (6.0 mg g-1 FM), carbohydrate (10.7 mg g-1 FM) and GDM (11.0%) levels than seeds forming normal seedlings after 21 days in culture. On the other hand, the protein content (9.1 mg g-1 FM) was significantly higher during induction. NCs induction process through seeds is the result of gene reprogramming in the explant, which leads to morphological, biochemical and metabolic alterations. This involves dedifferentiation, high cell proliferation, high energy demand and protein synthesis, which is related to elevated metabolic activity.