Variación del color de flores y números cromosómicos en el noroeste del área de distribución de Turnera sidoides (Turneraceae)

In the context of the evolutionary studies that are being carried out in Turners sidoides autopolyploid complex (x= 7), a systematic survey was made in the northwestern area (Bolivia) of its distribution. Six populations with salmon flowers and thirty five with yellow ones of the subsp. pinnatifida were found. The distribution of these populations is associated with climatic and spatial variables. The populations with salmon flowers live in the dry forests (Chaco Boreal Biogeographical Province), while yellow flowered populations occur in the inter-andean valleys (Boliviano-Tucumana Biogeographical Province). All the population studied are diploid. The results obtained support the allopatric diversification model of populations with yellow and salmon flowers at the diploid level, probably favoured by the orographic barriers and climatic changes that have arisen during the Andes development and Quaternary glaciations. Moreover, our analysis evidences that the north western area of T. sidoides constitutes an important centre of variation of the subsp. pinnatifida and the major centre of diploids hitherto detectedEn el marco de los estudios evolutivos que se desarrollan en el complejo autopoliploide Turnera sidoides (x= 7) se realizó un muestreo sistemático en el noroeste de su área de distribución. Se hallaron 6 poblaciones con flores de color salmón y 35 con flores amarillas de la subsp. pinnatifida. La distribución de estas poblaciones está asociada con variables climáticas y espaciales. Las poblaciones que presentan flores de color salmón viven en los bosques semiáridos (Provincia Biogeográfica del Chaco Boreal) y las de flores amarillas en los valles interandinos (Provincia Biogeográfica Boliviano-Tucumana). Todas las poblaciones analizadas son diploides. Los resultados obtenidos sustentan el modelo de diversificación alopátrica de las poblaciones con diferente color de flores a nivel diploide, probablemente favorecido por el sistema de barreras orográficas y los cambios climáticos surgidos a partir del levantamiento de los Andes y de las glaciaciones del Cuaternario. Además, el análisis evidencia que el noroeste del área de T. sidoides constituye un importante centro de variación de la subsp. pinnatifida y es el mayor centro de diploides hasta ahora detectad

Análisis de la producción y frecuencia de microsporas no reducidas en diploides de Turnera sidoides (Turneraceae) Analysis of the production and frequency of unreduced microspores in diploids of Turnera sidoides (Turneraceae)

Turnera sidoides es un complejo poliploide (x= 7) de hierbas rizomatosas, perennes y distilas, que incluye cinco subespecies. Debido a la alta frecuencia de poliploides en el complejo, los estudios que se llevan a cabo actualmente están orientados a la comprensión de los mecanismos involucrados en el origen y establecimiento de los mismos a fin de proveer evidencias sobre los patrones evolutivos que operan en T. sidoides. En este trabajo se investiga la producción y frecuencia de microsporas no reducidas en plantas diploides provenientes de nueve poblaciones naturales pertenecientes a cuatro subespecies de T. sidoides, mediante el análisis del rango de variación del tamaño del polen y de la constitución de las esporadas. Los resultados obtenidos mostraron que casi todas las poblaciones estudiadas producen microsporas 2x y 4x, tanto en las flores brevistilas como en las longistilas. Asimismo, el análisis realizado aportó evidencias que sustentan la poliploidización sexual como uno de los mecanismos involucrados en el origen de los poliploides dentro del complejo. Se discute, además, el papel del polen no reducido en el establecimiento y la persistencia de los poliploides formados de novo en las poblaciones diploides de la especie.Turnera sidoides is a polyploid complex (x= 7) of dystilous perennial rhizomatous herbs that includes five subspecies. Owing to the high frequency of polyploids within the complex, ongoing studies in T. sidoides are focused on the understanding of the mechanisms involved in the origin and the establishment of polyploids in order to provide evidences of the evolutionary patterns in T. sidoides. In this report we investigate the occurrence and frequency of unreduced microspores in diploid plants from nine natural populations of four subspecies of T. sidoides by analyzing the range of variation of pollen volume and the constitution of the sporads. The results obtained showed that almost all the populations studied produced 2x and 4x microspores, both in short and long-styled floral morphs. Furthermore, the analysis performed provided evidences that support the hypothesis of sexual polyploidization as one of the mechanisms involved in the origin of polyploids within this species complex. The role of unreduced pollen in the establishment and persistence of newly formed polyploids within diploid populations of T. sidoides is also discussed

Flower colour variation and chromosome numbers in the north western distributional area of <i>Turners sidoides</i> (Turneraceae)

In the context of the evolutionary studies that are being carried out in Turners sidoides autopolyploid complex (x= 7), a systematic survey was made in the northwestern area (Bolivia) of its distribution. Six populations with salmon flowers and thirty five with yellow ones of the subsp. pinnatifida were found. The distribution of these populations is associated with climatic and spatial variables. The populations with salmon flowers live in the dry forests (Chaco Boreal Biogeographical Province), while yellow flowered populations occur in the inter-andean valleys (Boliviano-Tucumana Biogeographical Province). All the population studied are diploid. The results obtained support the allopatric diversification model of populations with yellow and salmon flowers at the diploid level, probably favoured by the orographic barriers and climatic changes that have arisen during the Andes development and Quaternary glaciations. Moreover, our analysis evidences that the north western area of T. sidoides constitutes an important centre of variation of the subsp. pinnatifida and the major centre of diploids hitherto detected</div

The use of PLDLA/PCL-T scaffold to repair osteochondral defects in vivo

The physiological repair of osteochondral lesions requires the development of a scaffold that is compatible with the structure of the damaged tissue, cartilage and bone. The aim of this study was to evaluate the biological performance of a PLDLA/PCL-T (90/10) scaffold for repairing osteochondral defects in rabbits. Polymeric scaffolds containing saccharose (75% w/v) were obtained by solvent casting and then implanted in the medial knee condyles of 12 New Zealand rabbits after osteochondral damage with a trephine metallic drill (diameter: 3.3 mm) in both medial femoral condyles. Each rabbit received the same treatment, i.e., the polymeric scaffold was implanted on the right side while no material was implanted on the left side (control). Four and 12 weeks later histological examination revealed bone neoformation in the implant group, with the presence of hyaline cartilage and mesenchymal tissue. In contrast, the control group showed bone neoformation with necrosis, exacerbated superficial fibrosis, inflammation and cracks in the neoformed tissue. These findings indicate that the PLDLA/PCL-T scaffold was biocompatible and protected the condyles by stabilizing the lesion and allowing subchondral bone tissue and hyaline cartilage formation