Seed structure and in vitro seedling development of certain Laeliinae species (Orchidaceae)

Abstract

Seeds and seedlings of neotropical Laeliinae species (Cattleya loddigesii, Cattleya tigrina, Hadrolaelia purpurata, Laelia anceps, Schomburgkia gloriosa, and Sophronitis cernua) were studied. The seed germination process and the seedling grown in vitro are described. Seeds of the studied species are unitegmic and have conspicuous thickening in the anticlinal and inner periclinal cell walls. The embryo consists of a relatively long and multicellular suspensor. At first stage of seedling development, the embryo differentiates into a protocorm with rhizoids and meristematic tissue. The budding occurs on the protocorms. The endogenous taproot is produced after the first leaves have emerged. The root is triarch or tetrarch and it possesses velamen. Structural characters related to seed coat, suspensor, ontogeny of leaves, and vascular system of the root are significant indicators for the separation of Laeliinae species. All Rights Reserved ResumenEn este trabajo se realizó un análisis comparativo de semillas y plántulas en especies neotropicales de la subtribu Laeliinae (Cattleya loddigesii, C. tigrina, Hadrolaelia purpurata, Laelia anceps, Schomburgkia gloriosa, y Sophronitis cernua). Se describe el proceso de germinación de semillas y el desarrollo de plántulas cultivadas in vitro. Las semillas presentan un tegumento con un engrosamiento visible en las paredes. El embrión tiene un suspensor multicelular alargado. En la primera etapa del desarrollo de la plántula, el embrión se transforma en un protocormo con rizoides y tejido meristemático en el que aparecen los brotes primordiales. La raíz primaria se produce después de las hojas, es de tipo triarca o tetrarca con velamen. En conclusión, las características estructurales asociadas con la cubierta seminal, el desarrollo ontogenético de la hoja y el sistema vascular de la raíz, son indicadores significativos para la identificación de las especies estudiadas de Laeliinae. Derechos Reservados © 2016 Universidad Nacional Autónoma de México, Instituto de Biología. Este es un artículo de acceso abierto distribuido bajo los términos de la Licencia Creative Commons CC BY-NC-ND 4.0.

Comparative Seed Morphology of Tropical and Temperate Orchid Species with Different Growth Habits

“…Most orchid species are endangered because of over collection and loss of habitat, so there is an urgent need to develop techniques to conserve them both in situ as well as ex situ [1]. Seed morphology is an important trait related to biological and ecological processes such as seed dormancy and germination [2,3], adaptation to habitat for seed dispersal [4][5][6][7], and seed storability [8]. Therefore, investigating seed morphology is relevant to understanding the plant's reproduction under natural conditions and to devise optimal protocols for seed storage and propagation.…”

Asymbiotic seed germination and in vitro propagation of Cattleya trianae Linden & Reichb.f. (Orchidaceae)

“…This is in concordance with other authors, where the effectiveness of the organic components (pineapple juice and coconut water) have allowed a verification in the in vitro culture of a great variety of orchid species. (Gallo et al, 2016;Salazar et al, 2013). Nonetheless, Pedroza (2009), found that the addition of AIA (0.5 mg.L -1 ) to the MS culture medium, promoted the development phases of Epidendrum elongatum.…”

“…Several authors have achieved asimbiotic germination using different simple means with minerals, vitamins, hormones and sugars (Kauth et al, 2011;Arditti & Ghani, 2000;Knudson, 1946). Likewise, cultures have been improved supplementing the media with organic components (Gallo et al, 2016;Salazar et al, 2013;Salazar & Cancino, 2012). The present research aims to determine the most suitable culture medium for asymbiotic seed germination and in vitro propagation of C. trianae for the species conservation.…”

Seed Micromorphology, In Vitro Germination, and Early-Stage Seedling Morphological Traits of Cattleya purpurata (Lindl. & Paxton) Van den Berg

“…As recently reported by Caballero-Villalobos et al [16], the species is nectarless and self-compatible, although it is pollinator-dependent. Some morphological investigations on the vegetative portions of this species have been carried out by Silva Júnior et al [17] and Gallo et al [18]. The former studied leaf characteristics and chlorophyll content of this species after the applications of different urea concentrations during in vitro experiments.…”

“…The former studied leaf characteristics and chlorophyll content of this species after the applications of different urea concentrations during in vitro experiments. Gallo et al [18] performed an anatomical investigation on seed and protocorm from six species belonging to the genus Cattleya, C. purpurata included. Anatomical investigations provide important information to assess species identity, to better understand physiological processes, or to study phylogenetic relationships between taxa [19].…”