Macro- and micromorphology of the root, stem leaf, infloresence and fruit of Euphorbia peplus L. growing in Egypt

Euphorbia peplus L. belongs to Family Euphorbiaceae which includes about 283 genera with almost 7500 species. They are distributed all over the world mainly tropical countries. Some species of the genus Euphorbia showed antiviral and anticancer activities. It was reported to be used in folkloric medicine as purgative and in treatment of skin diseases, gonorrhea, liver disorders, chest diseases, and gout. Some phytochemical studies have been carried out abroad on different species. The authors carried out phytochemical and biological studies on the studied plant and here in we undertake macro- and micromorphological studies with the aim of finding out the diagnostic features by which the plant could be identified in both entire and powdered forms

Primary and secondary thickening in the stem of Cordyline fruticosa (Agavaceae)

The growth in thickness of monocotyledon stems can be either primary, or primary and secondary. Most of the authors consider this thickening as a result of the PTM (Primary Thickening Meristem) and the STM (Secondary Thickening Meristem) activity. There are differences in the interpretation of which meristem would be responsible for primary thickening. In Cordyline fruticosa the procambium forms two types of vascular bundles: collateral leaf traces (with proto and metaxylem and proto and metaphloem), and concentric cauline bundles (with metaxylem and metaphloem). The procambium also forms the pericycle, the outermost layer of the vascular cylinder consisting of smaller and less intensely colored cells that are divided irregularly to form new vascular bundles. The pericycle continues the procambial activity, but only produces concentric cauline bundles. It was possible to conclude that the pericycle is responsible for the primary thickening of this species. Further away from the apex, the pericyclic cells undergo periclinal divisions and produce a meristematic layer: the secondary thickening meristem. The analysis of serial sections shows that the pericycle and STM are continuous in this species, and it is clear that the STM originates in the pericycle.The endodermis is acknowledged only as the innermost layer of the cortex.

O crescimento em espessura do caule de monocotiledônea pode ser primário, ou primário e secundário. A maioria dos autores consideram o espessamento resultante do MEP (Meristema de Espessamento Primário) e do MES (Meristema de Espessamento Secundário). Há divergências de qual seria o meristema responsável pelo espessamento primário. Em Cordyline fruticosa o procâmbio forma feixes vasculares de dois tipos: traços foliares colaterais (com proto e metaxilema e proto e metafloema), e feixes caulinares concêntricos (com metaxilema e metafloema). O procâmbio também forma o periciclo, a camada mais externa do cilindro vascular, constituída por células menores e menos coradas que se dividem irregularmente, formando novos feixes vasculares. O periciclo dá continuidade à atividade procambial, originando somente feixes concêntricos. Concluiu-se ser o periciclo responsável pelo espessamento primário desta espécie. Mais distante do ápice as células pericíclicas passam a sofrer divisões periclinais originando o Meristema de Espessamento Secundário. A análise dos cortes seriados mostra que o periciclo e o MES são contínuos nesta espécie, ficando claro que o periciclo origina oMES. A endoderme é reconhecida, apenas, como a camada mais interna do córtex.

Stem anatomical characteristics of the climbing palm Desmoncus orthacanthos (Arecaceae) under two natural growth conditions in a tropical forest

Desmoncus orthacanthos is a Neotropical climbing palm that resembles rattan and therefore has similar potential applications. The genus Desmoncus (subfamily Arecoideae, subtribe Bactridinae) is distributed throughout the Americas, from veracruz, Mexico, to Brazil and Bolivia. The anatomical characteristics of its support tissue have not been thoroughly studied, although some observations from Central American artisans suggest that the stems collected from undisturbed sites possess better characteristics; these include a good capacity to withstand bending without breaking (i.e. higher fracture strength than plants from disturbed sites). Stem samples were collected from individuals from disturbed and undisturbed sites, at three points along the length of the stem (basal, medium and apical). Collections were made of one ramet from five individuals (n=5) at both sites. Each ramet was divided into three sections: basal, from soil surface to a height of 0.5 m; medium, from a height of 0.5 to 5.0 m; and apical, from a height 5.0 to 10.0 m. An anatomical analysis including vascular bundles, parenchyma elements and fibers was performed in the radial direction and also along the longitudinal direction of the stems. The amount of vascular bundles was greater for samples from undisturbed site stems; the amount of parenchyma cells differ between samples from both sites and the amount of fibers was greater for samples from disturbed site stems. The anatomical structural dimensions were smaller for samples from the undisturbed site stems. These findings partially confirm the artisans’ belief and supports the conclusion that microclimatic conditions affect plant anatomical structure. Rev. Biol. Trop. 56 (2): 937-949. Epub 2008 June 30.

Desmoncus orthacanthos es una palmera trepadora neotropical que puede, potencialmente, utilizarse en usos similares a los del ratán. El género Desmoncus (subfamilia Arecoideae, subtribu Bactridinae) se distribuye en América desde Veracruz, Mexico, hasta Brasil y Bolivia. Esta especie posee características anatómicas que no han sido ampliamente estudiadas pero observaciones hechas por artesanos centroamericanos sugieren que los tallos de sitios no perturbados por actividades humanas presentan mayor resistencia al doblado y menos tallos fracturados en el manejo. Las muestras de tallos fueron recolectadas de individuos que crecen en un sitio conservado y uno perturbado por actividades humanas, a tres alturas de la longitud del tallo (basal, media y apical). Se recolectó una rama de cada uno de cinco individuos (n=5) en ambos sitios. Cada rama fue dividida en tres secciones: basal, desde el nivel del suelo hasta los 0.5 m; medio, desde 0.5 a 5.0 m; y apical, desde 5.0 a 10.0 m. Se midió la cantidad por unidad de área y las dimensiones o tamaño (i.e. diámetro radial y diámetro perpendicular) de paquetes vasculares, células de parénquima y fibras. La cantidad de paquetes vasculares fue mayor en los tallos del sitio conservado, la cantidad de células de parénquima fue diferente entre sitios y la cantidad de fibras fue mayor en los tallos del sitio perturbado por actividades humanas. Estas características muestran cierta relación con los resultados mecánicos en otro estudio de los autores, los cuales confirman parcialmente las observaciones de los artesanos, lo que puede estar estrechamente relacionado con las características microclimáticas de los sitios de crecimiento.