Moemy Gomes de Moraes

Anatomy and fructan distribution in vegetative organs of Dimerostemma vestitum (Asteraceae) from the campos rupestres

Among the compounds stored by plants, several functions are assigned to fructans, such as source of energy and protection against drought and extreme temperatures. In the present study we analyzed the anatomy and distribution of fructans in vegetative organs of Dimerostemma vestitum (Asteraceae), an endemic species from the Brazilian campos rupestres. D. vestitumhas amphistomatic and pubescent leaves, with both glandular and non-glandular trichomes. In the basal aerial stem the medulla has two types of parenchyma, which differ from the apical portion. The xylopodium has mixed anatomical origin. Interestingly, although inulin-type fructans with high degree of polymerization were found in all analyzed organs except the leaves, the highest amount and maximum degree of polymerization were detected in the xylopodium. Inulin sphero-crystals were visualized under polarized light in the medulla and in the vascular tissues mainly in the central region of the xylopodium, which has abundant xylem parenchyma. Secretory structures accumulating several compounds but not inulin were identified within all the vegetative organs. The presence of these compounds, in addition to inulin, might be related to the strategies of plants to survive adverse conditions in a semi-arid region, affected seasonally by water restriction and frequently by fire.

Morpho-anatomy and fructans in the underground system of Apopyros warmingii and Ichthyothere terminalis (Asteraceae) from the cerrado rupestre1

Abstract The cerrado rupestre is a physiognomy of the Cerrado biome with a prominent ground layer. It is characterized by rocky outcrops; acidic, nutrient-poor soil; and water shortage due to climatic seasonality. Species of this biome have several mechanisms to survive these adverse conditions. This study aimed to investigate morpho-anatomical characteristics and soluble carbohydrates in underground systems of Apopyros warmingii and Ichthyothere terminalis (Asteraceae), and to evaluate the potentially adaptive roles of these structures under the environmental stressors of the cerrado rupestre. Samples of underground organs were fixed, dehydrated in graded ethylic ethanol, embedded in historesin, and sectioned. Qualitative and quantitative analyses of soluble carbohydrates were performed in distinct portions of the underground systems. Thickened underground systems of both species are composed of stem and root portions with buds in the proximal region. Vascular and cortical parenchymas are abundant and accumulate inulin, which can be visualized as spherocrystals. Secretory structures have lipophilic secretion. High fructan amounts in the parenchyma indicate their use to support resprouting. These carbohydrates may be mobilized to meet the increased demands of phenology and abiotic factors. Secretory structures and sclereids in both species and raphides in A. warmingii may assist the protection of the underground system against herbivores.

Avaliação do potencial interpretativo da trilha do Jequitibá, Parque Estadual dos Três Picos, Rio de Janeiro

O presente estudo avaliou o potencial da trilha do Jequitiba, Parque Estadual dos Tres Picos (RJ), para a sensibilizacao e conscientizacao dos seus usuarios atraves da Interpretacao Ambiental. Foram utilizadas as metodologias de caracterizacao biofisica da trilha, avaliacao da trilha quanto a Interpretacao Ambiental e o Indice de Atratividade dos Pontos Interpretativos (IAPI). A trilha do Jequitiba foi caracterizada como de leve dificuldade, curto percurso, com design apropriado para pedestres, sendo os impactos decorrentes do uso considerados minimos ou controlados. Atraves do IAPI, pode-se concluir que e uma trilha altamente atrativa, dotada de uma multiplicidade de recursos interpretativos. Apesar de possuir pontos de interpretacao consensuais, estes enfatizam conteudos biologicos e ecologicos em detrimento dos de cunho historico e cultural, alem de nao apresentar roteiros tematicos de interpretacao definidos. Embora nao atenda a todos os pressupostos da Interpretacao Ambiental, a trilha do Jequitiba pode ser considerada com carater e potencial interpretativo, no entanto, os aspectos frisados devem ser trabalhados de forma a implementar e desenvolver plenamente a Interpretacao Ambiental.

Seasonal changes of fructans in dimorphic roots of Ichthyothere terminalis (Spreng.) Blake (Asteraceae) growing in Cerrado

Cerrado is a floristically rich savanna in Brazil, whose vegetation consists of a physiognomic mosaic, influenced by rainfall seasonality. In the dry season rainfall is substantially lower and reduces soil water supply, mainly for herbs and subshrubs. Climatic seasonal variations may well define phenological shifts and induce fluctuations of plant reserve pools. Some Cerrado native species have thickened underground organs that bear buds and store reserves, as adaptive features to enable plant survival following environmental stresses. Asteraceae species accumulate fructans in storage organs, which are not only reserve, but also protecting compounds against the effects of cold and drought. Ichthyothere terminalis is one Asteraceae species abundant in cerrado rupestre, with underground organs consisting of thickened orthogravitropic and diagravitropic roots. The objectives of this study were to analyze how abiotic environmental factors and plant phenology influence fructan dynamics in field grown plants, and verify if fructan metabolism differs in both root types for one year. I. terminalis accumulates inulin-type fructans in 10-40% of the dry mass in both root types. Fructan dynamics have similar patterns described for other Asteraceae species, exhibiting a proportional increase of polysaccharides with the senescence of the aerial organs. Multivariate analyzes showed that, as rainfall decreased, environmental factors had a stronger influence on metabolite levels than phenological shifts in both root types. Only slight differences were found in fructan dynamics between orthogravitropic and diagravitropic roots, suggesting they may have similar fructan metabolism regulation. However, these small differences may reflect distinct microclimatic conditions in both root types and also represent the influence of sink strength.