ABSTRACT
Hypochaeris is an excellent system for studying different modes of chromosome evolution in plants. We carried out a cytogenetic analysis on populations of 2 Hypochaeris species, comprising 10 populations of H. catharinensis and 5 of H. lutea, to assess possible changes on chromosome organization in this interesting genus. Conventional Feulgen staining and fluorescent banding revealed that the general aspects of chromosome morphology for all populations of both species were similar, evidence of the typical bimodal karyotypes with 2n = 8 chromosomes that characterize the South American Hypochaeris. Comparative analysis of the karyotypes identified minor variations in the absolute size and arm ratio of corresponding chromosome pairs. One population of H. lutea was entirely polyploid adding a novel cytotype to this species. Fluorescent banding revealed strong chromomycin A3 (CMA3)-positive signals on both arms of chromosomes 3 and 4 of H. catharinensis, revealing a new pattern for the distribution of GC-rich heterochromatin in Hypochaeris. A strong CMA-positive signal was observed on the short arm of chromosome 3 in one population of H. lutea, while the other populations validated the CMA3 pattern already described for this species. While the overall karyotype similarities of the 2 species are in compass with all South American Hypochaeris, the presence of unusual large blocks of GC-rich heterochromatin suggests that chromosome rearrangements, related to dispersion of heterochromatin, are taking place in the karyotype of H. catharinensis. The novel polyploid cytotype identified in H. lutea provides support that polyploidization is an active process in the mode of chromosome evolution in Hypochaeris.
Subject(s)
Asteraceae/genetics , Karyotype , Karyotyping , Brazil , Chromosome Banding , Chromosomes, Plant/genetics , DiploidyABSTRACT
Baccharis rufescens Spreng. var. tenuifolia (DC.) Baker pertence à família Asteraceae e é usada na medicina tradicional como estomáquico e hepatoprotetor. Um estudo fitoquímico mostrou a presença de flavonoides e triterpenos, sendo que os extratos clorofórmico e metanólico de folhas apresentaram-se ativos no bioensaio de toxicidade sobre Artemia salina Leach. Além disso, extratos clorofórmicos evidenciaram a presença de peróxidos, sugerindo sua aplicação no tratamento da malária (Schenkel at al., 2002; Montanher et al., 2002; Moreira et al., 2003). Considerando a importância farmacológica de B. rufescens var. tenuifolia, o presente trabalho objetivou o estudo morfoanatômico e histoquímico do caule e da folha dessa espécie, a fim de fornecer subsídios farmacognósticos para o controle de qualidade. O material botânico foi submetido às técnicas usuais empregadas na microscopia de luz e microscopia eletrônica de varredura. Folha anfiestomática, presença de estômatos anomocíticos, tricomas glandulares capitados bisseriados, tricomas tectores flageliformes simples unisseriados, dutos secretores associados ao floema, calota de fibras perivasculares e cristais de oxalato de cálcio do tipo estiloide e prismático na região medular do caule foram as principais características observadas que auxiliam na identificação do táxon.
Baccharis rufescens Spreng. var. tenuifolia (DC.) Baker belongs to the Asteraceae family. It is used for liver and stomach problems in traditional medicine. Previous phytochemical data reported flavonoid and triterpene contents. Chloroform and methanol extracts of the leaves showed activity in the bioassay of brine shrimp. Chloroform extracts showed the presence of peroxides that can be used to treat malaria (Schenkel et al., 2002; Montanher et al., 2002; Moreira et al., 2003). Considering the pharmacological importance of B. rufescens var. tenuifolia, the purpose of this paper was to perform the anatomical analysis of aerial vegetative parts of Baccharis rufescens var. tenuifolia in order to provide pharmacognostic data for quality control. The plant material was studied by the usual methods of light and scanning electron microscopy. Amphistomatic leaves, anomocytic stomata, biseriate capitate glandular trichomes, uniseriate simple flagelliform non-glandular trichomes, secretory ducts associated to the phloem, perivascular fiber cap, calcium oxalate as prismatic and styloid crystals in the pith of the stem were reported as the mainly anatomical data for B. rufescens var. tenuifolia.Ouvir Ler foneticamente.
Subject(s)
Pharmacognosy/methods , Asteraceae/classification , Microscopy, Electron, Scanning , Baccharis/classificationABSTRACT
Baccharis é um importante gênero da família Asteraceae que compreende aproximadamente 500 espécies, todas americanas, das quais aproximadamente 120 ocorrem no Brasil. Muitos autores como De Candolle, Baker, Heering, Cuatrecasas, Ariza Espinar, Barroso e Giuliano têm tentado estruturar uma adequada divisão do gênero em subgêneros e seções. Espécies desse gênero são importantes economicamente para o homem, pois ajudam no combate à erosão e podem ser utilizadas como plantas ornamentais, mas também podem apresentar-se como pragas de difícil combate em pastagens, podendo intoxicar o gado. Contudo, o destaque maior está na medicina, onde vários representantes são utilizados popularmente. Nesse contexto várias espécies têm sido investigadas contribuindo para a elucidação morfoanatômica e para o controle de qualidade.
Baccharis is an important genus of the Asteraceae family, which comprises about 500 American species, including 120 species from Brazil. Several authors such as De Candolle, Baker, Heering, Cuatrecasas, Ariza Espinar, Barroso and Giuliano have attempted to elaborate an adequate genus division in subgenera and sections. Baccharis species are economically important since they help to prevent erosion and are employed as ornamental plants, although they can become weeds of difficult control in grazing and poison to the cattle. However, in the folk medicine, many species are relevant and have been studied, aiming to contribute to their morpho-anatomical and quality control knowledge.
