Peculiar anatomical traits, high durability, and potential ornamental use of Cyclanthaceae as fresh foliage

ABSTRACT Wild plant species with potential for use as ornamental green foliage are often reported. Nevertheless, there are few studies evaluating morphological and anatomical aspects associated with this use. Preliminary trials suggest that the species of Sphaeradenia (Sander ex Mast.) Harling, a Cyclantaceae that occurs from Costa Rica to Peru, is suitable to be used as fresh foliage because of attractiveness of their leaves in vase and its durability without showing tissue damage, compared with other genera of this family. Through the study of anatomical characters, it is possible to predict the potential of a species that can serve as ornamental foliage. In this study, three foliar anatomical features (thickness of the cuticle and leaf, and percentage of fibers in the mesophyll) of seven Cyclanthaceae species were evaluated, using anatomical techniques and image analysis with the LUCIA® and ImageJ softwares. Statistical analysis of the results suggests that this high durability is associated with the thickness of the cuticle and mesophyll, but not with the amount of fibers in the leaf.

Structure and distribution of glandular trichomes in three species of Bignoniaceae / Estrutura e distribuição de tricomas glandulares em três espécies da família Bignoniaceae

Glandular trichomes play a major role in the morphological characterization of the Bignoniaceae. Due to their great diversity of forms and functions, this study aimed to inventory the glandular trichomes present in the aerial vegetative axis of Amphilophium magnoliifolium, Martinella obovata and Stizophyllum riparium, analyze their structure and register the participation of ants in these plants. Fresh samples from the nodal region, petiole and from medium to apical regions of the leaflet blade were fixed and processed according to usual methods in light and scanning electron microscopies. The glandular trichomes found were: peltate, capitate, stipitate, and patelliform/cupular. Peltate trichomes are the most abundant ones and present the most uniform distribution. Patelliform/cupular trichomes occur at specific regions, such as prophylls, leaflet blade and nodal regions. Martinella obovata is the only species that presents capitate and stipitate trichomes, which are widely distributed along the entire aerial vegetative axis. Ants were found in all species, mainly at nodal regions. The occurrence of the capitate-type trichome is reported for the first time to the genus.

Tricomas glandulares desempenham papel importante na caracterização morfológica de Bignoniaceae e, devido à grande diversidade de formas e funções que esses tricomas apresentam, o objetivo desse estudo foi inventariar os tricomas glandulares presentes no eixo vegetativo aéreo de Amphilophium magnoliifolium, Martinella obovata. e Stizophyllum riparium, bem como analisar sua estrutura e registrar a participação de formigas nessas espécies. Amostras frescas da região mediana à apical das lâmina foliolar, pecíolo e nó foram fixadas e processadas de acordo com os métodos usuais para microscopia de luz e eletrônica de varredura. Os tricomas glandulares encontrados nas espécies foram: peltados, capitados, estipitados e pateliformes/cupuliformes. Dentre esses tipos o mais abundante foi o tricoma peltado, apresentando também uma distribuição mais uniforme que os demais. Os tricomas pateliformes/cupuliformes estavam em regiões mais específicas, como profilos, lâmina foliolar e na região nodal. Martinella obovata foi a única espécie que apresentou os tricomas capitados e estipitados, amplamente distribuídos ao longo de todo eixo vegetativo aéreo. Em todas as espécies foram encontradas formigas, principalmente nas regiões nodais. A ocorrência do tricoma capitado é relatada pela primeira vez para o gênero.

Calicinal trichomes of Adenocalymma magnificum (Bignoniaceae) producing lipophilic substances: ultrastructural and functional aspects / Tricomas calicinales de Adenocalymma magnificum (Bignoniaceae) que producen sustancias lipofílicas: aspectos ultraestructurales y funcionales

Plant structures that secrete lipids and phenolic compounds are often associated with the protection and development of organs against desiccation, in addition to the protection they provide against animals, as the capitate trichomes of Adenocalymma magnificum. Understanding the glandular activities that occur in these trichomes has required the study of their ontogeny, structure, ultrastructure and histochemical aspects; the interpretation of their ecological functions or evolutionary history is complicated by the scarcity of reports on calicinal trichomes that are not nectar-secreting. Samples of floral calyx in anthesis and flower buds at different stages of development were fixed and processed according to the methods for light and electron microscopy. The trichomes are randomly distributed throughout the entire inner surface of the calyx and are also visible on the flower buds. These capitate glandular trichomes were composed of a peduncle, having up to nine cells, and a multicellular secretory head with their cells in columnar format and arranged in disc form. The collar cell, which is under the secretory head, divides anticlinally and arranges itself side by side with the mother cell. As they develop, they bend with some of them becoming adpressed to the calyx. Histochemical tests indicate that the secretory head cells produce lipid substances, acidic lipids and phenolic compounds. In the secretory head, the vacuome is dispersed and the cytoplasm possesses a great number of smooth endoplasmic reticulum and leucoplasts, organelles involved in the production of osmiophilic substances. In some regions of the secretory cells, cuticle detachment was observed; however, the accumulation of secretions was not observed. This study describes, for the first time, the origin, development, and secretion process of the calicinal trichomes of Adenocalymma magnificum, showing that production of lipophilic substances is important for this plant, possibly the trichomes may be involved in the plant’s chemical defense against insects, offering protection against herbivores. Rev. Biol. Trop. 63 (2): 537-544. Epub 2015 June 01.

Las estructuras que secretan lípidos y compuestos fenólicos estan frecuentemente asociadas a la protección y desarrollo de órganos que protegen contra la desecación, además de la protección que estas proporcionan contra el ataque de animales. Los tricomas capitados de Adenocalymma magnificum son estructuras de este tipo. Para comprender las actividades glandulares que ocurren en estos tricomas es necesario estudiar su ontogenia, estructura, ultraestructura y aspectos histoquímicos. La interpretación de sus funciones ecológicas o historia evolutiva es compleja, y pocos son los estudios que se enfocan en los tricomas calicinales no secretores de néctar. Las muestras del cáliz floral en antesis y botones florales en diferentes estadios de desarrollo fueron fijadas y procesadas de acuerdo con los métodos para microscopia de luz y electrónicos. Los tricomas de A. magnificum están aleatoriamente distribuidos en toda la extensión de la superficie interna del cáliz, también observados en los botones florales. Estos tricomas son glandulares capitados, compuestos de un pedúnculo largo que posee hasta nueve células y una cabeza secretora multicelular, con células en columnares dispuestas en disco. La célula del collar, que esta sobre las células de la cabeza secretora, se divide anticlinalmente organizándose lado a lado con las células madre. Con el crecimiento de los tricomas, estos mismos se curvan y algunos quedan adpresos al cáliz. Las pruebas histoquímicas indicaron que las células de la cabeza secretora producen sustancias lipídicas, lípidos ácidos y compuestos fenólicos. En la cabeza secretora la vacuoma esta dispersa y posee abundante retículo endoplasmático liso y leucoplastos, los cuales son organelos involucrados en el proceso de producción de sustancias osmiofílicas. En algunas regiones de las células secretoras la distensión de la cutícula fue observada, sin embargo, no fue verificada la acumulación de secreción. Este trabajo describe por primera vez el origen, desarrollo y proceso de secreción de tricomas calicinales de A. magnificum, mostrando que la producción de substancias lipofílicas es importante para esta especie, ofreciendo posiblemente protección contra la herbivoría.

Micromorfologíayy histoquímica de los laticífers de órganos vegetativos de esppecies de asclepiadoideae (apocynaceae) / Micromorphology and Histochemistry of the Laticifers from Vegetative Organs of Asclepiadoideae species (Apocynaceae)

La micromorfología y las principales clases de componentes de las paredes de los laticíferos y del látex de Asclepias curassavica, Fischeria stellata, Gonioanthela axillaris, Matelea denticulata y Oxypetalum banksii, fueron analizadas y comparadas con las de especies de Apocynaceae de Cerrado. Los laticíferos de las especies estudiadas de diferentes tipos de bosques presentan características semejantes. Las paredes son primarias, altamente hidratadas, pecto-celulósicas y fuertemente adheridas a las paredes de las células adyacentes. El látex es blanco lechoso, constituido por polisacáridos, incluyendo mucílago, proteínas, lípidos, incluyendo ácidos grasos, compuestos fenólicos e alcaloides. Fischeria y Gonioanthela difieren de las demás especies por producir lípidos neutros. El látex de las especies investigadas está asociado a la protección de la planta contra herbivoría, pudiendo ser tóxico e inhibir la proliferación de microorganismos, además de coagular, sellando heridas de las plantas y funcionando como barrera física. Estas propiedades del látex proporcionan una mayor ventaja adaptativa a estas plantas en relación a las no latescentes.

Micromorphology and main substances of the laticifer walls and latex of Asclepias curassavica, Fischeria stellata, Gonioanthela axillaris, Matelea denticulata, and Oxypetalum banksii were analyzed and compared with those of Apocynacean Cerrado species. Laticifers of the studied species from different rainforest vegetations exhibit similar features. The walls are primary, highly hydrated, pectic-cellulosic, and firmly attached to adjacent cell walls. The latex is milky white, constituted by polysaccharides, including mucilage, proteins, lipids, including fatty acids, phenolic compounds, and alkaloids; however, Fischeria and Gonioanthela differ from the other species for also producing neutral lipids. The latex of the investigated species is related to plant defense against herbivory, and may be toxic and inhibit microorganism proliferation. Also, it can coagulate, sealing plants wounds and working as a physical barrier. These latex properties provide greater adaptive advantage to these plants in relation to non-latescent plants.

Leaf anatomical features of three Theobroma species (Malvaceae s.l. ) native to the Brazilian Amazon / Caracteres anatômicos foliares de três espécies de Theobroma (Malvaceae s.l. ) nativas da Amazônia Brasileira

Theobroma species have economic importance due to their use in the cosmetic and food industries, mainly in the production of chocolate. However, the anatomy of their vegetative structures remains poorly studied. The goal of this study was to describe the anatomical features of Theobroma grandiflorum, T. speciosum and T. subincanum to contribute to the biological knowledge of these species, as well as provide support to the biotechnological studies of native fruit plants of the Amazon. Leaves at different developmental stages were collected and analyzed under light microscopy and scanning electron microscopy. Sessile and stalked stellate trichomes and digitiform glandular trichomes were observed in the expanded leaves of T. grandiflorum and T. subincanum. These species were also similar in the morphology of the midrib, the organization of the mesophyll and the presence of starch grains in the midrib pith cells. Claviform glandular trichomes and mucilage cells in the epidermis occurred only in the expanded leaves of T. speciosum. The presence of mucilage secretory trichomes in shoot apices (colleters) of all species is a new finding for the genus Theobroma.

As espécies de Theobroma têm importância econômica devido a sua utilização nas indústrias cosmética e alimentícia, principalmente na produção de chocolate. Entretanto, a anatomia de suas estruturas vegetativas permanece pouco conhecida. O presente estudo teve por objetivo descrever as características anatômicas de Theobroma grandiflorum, T. speciosum e T. subincanum, como contribuição ao conhecimento biológico dessas espécies, bem como, fornecer subsídios aos estudos biotecnológicos de fruteiras nativas da Amazônia. Folhas em diferentes estágios de desenvolvimento foram coletadas e analisadas sob microscopia de luz e eletrônica de varredura. Nas folhas expandidas de T. grandiflorum e T. subincanum foram observados tricomas dos tipos estrelado séssil, pedunculado e glandular digitiforme. Estas espécies também foram similares quanto à morfologia da nervura central, à organização do mesofilo e à presença de grãos de amido no parênquima medular da nervura central. Tricomas glandulares claviformes e células mucilaginosas na epiderme do limbo foliar ocorreram somente em T. speciosum. A presença de tricomas secretores de mucilagem nos ápices vegetativos (coléteres) de todas as espécies estudadas é um novo registro para o gênero Theobroma.