ABSTRACT Atriplex lampa (Moq.) D. Dietr. is a halophytic, dioecious shrub native to Patagonia, Argentina. Although relatively neglected by science, it is important for sand-stabilization and for biomass and fodder production due to its nutritional characteristics and acceptable percentage of gross protein. The objective of this study is to provide cytological and morpho-anatomical information about A. lampa, which could be useful when applied in recovery and repopulation plans intending to use this species in areas degraded by petroleum industry activity. Natural populations in the Province of Chubut (45°-46° S; 67°- 68° W), Argentina, were studied. Karyotypes and meiotic behavior were analyzed according to conventional protocols, as were anatomical and morphological comparisons. Analysis of variance was used to test morphometrical differences between populations and cytotypes. Voucher specimens are deposited at the Facultad de Ciencias Naturales, Universidad Nacional San Juan Bosco de Patagonia, Argentina. Our results show that A. lampa has two cytotypes: diploids (2n = 2x = 18) and tetraploids (2n = 4x = 36). The stems and roots have anomalous secondary growth, and the leaves are amphistomatic, with a Kranz structure, and are covered with dense glandular trichomes. The leaves and fruit bracteoles are different sizes in the two cytotypes.

RESUMEN Atriplex lampa (Moq.) D. Dietr. es una especie que habita en ambientes áridos y suelos salinos, produce considerable cantidad de biomasa, aportando forraje de buena calidad en épocas de receso invernal. En Argentina, Provincia de Chubut, Departamento de Escalante, se observaron dos poblaciones naturales fenotípicamente diferentes. El objetivo de este trabajo fue estudiarlas citológica, exo y endomorfológicamente a fin de comprobar si las variantes fenotípicas responden a variaciones en el número somático. Por primera vez se presenta el análisis cariotípico y meiótico de la especie. Hasta el momento la especie era descrita como diploide, 2 n = 2 x = 18, en este estudio se encontró un citotipo tetraploide 2n = 4x =36. Las diferencias entre ambos citotipos se basan en el número somático, la morfología cromosómica, el comportamiento meiótico, el porte arbustivo y el tamaño de hojas y bractéolas fructíferas. La fórmula cariotípica, longitud genómica total y rango de variación en longitud cromosómica no se alejan de los valores observados para otras especies del género. Durante la meiosis se observa formación de tetravalentes, evidenciando alta homología entre los genomas lo que justifica su origen autopoliploide, que aún no alcanzó la diploidización. La formación de puentes y fragmentos durante anafase I sugiere la existencia de dos pares de cromosomas homólogos, heterocigóticos estructurales, para inversiones paracéntricas. La presencia de puentes en la segunda división indica recombinación meiótica en un amplio segmento invertido. Las observaciones y mediciones exomorfológicas dan resultados significativos para el tetraploide. Los caracters endomorfológicos se mantienen constantes en ambos niveles de ploidía al igual que el espesor de la hoja.

The present study analyzes the ectopic development of the rat skeletal muscle originated from transplanted satellite cells. Satellite cells (10(6) cells) obtained from hindlimb muscles of newborn female 2BAW Wistar rats were injected subcutaneously into the dorsal area of adult male rats. After 3, 7, and 14 days, the transplanted tissues (N = 4-5) were processed for histochemical analysis of peripheral nerves, inactive X-chromosome and acetylcholinesterase. Nicotinic acetylcholine receptors (nAChRs) were also labeled with tetramethylrhodamine-labeled alpha-bungarotoxin. The development of ectopic muscles was successful in 86% of the implantation sites. By day 3, the transplanted cells were organized as multinucleated fibers containing multiple clusters of nAChRs (N = 2-4), resembling those from non-innervated cultured skeletal muscle fibers. After 7 days, the transplanted cells appeared as a highly vascularized tissue formed by bundles of fibers containing peripheral nuclei. The presence of X chromatin body indicated that subcutaneously developed fibers originated from female donor satellite cells. Differently from the extensor digitorum longus muscle of adult male rat (87.9 ± 1.0 µm; N = 213), the diameter of ectopic fibers (59.1 µm; N = 213) did not obey a Gaussian distribution and had a higher coefficient of variation. After 7 and 14 days, the organization of the nAChR clusters was similar to that of clusters from adult innervated extensor digitorum longus muscle. These findings indicate the histocompatibility of rats from 2BAW colony and that satellite cells transplanted into the subcutaneous space of adult animals are able to develop and fuse to form differentiated skeletal muscle fibers.