Resprouting is a functional trait in species which occur in fi re-prone ecosystems. These plants can resprout from aerial buds and by recruiting belowground bud bank using carbohydrates allocated in roots as resource. In this study, we present morpho-anatomical features and chemical composition related to the resprouting potential of two species of Eugenia L. in an area of the Cerrado (Brazilian savanna) under regeneration, after the clear-cutting of Pinus sp. with the later burning of pine needles layer. We used standard histological techniques for belowground organs analysis and aerial buds protection degree. Belowground buds in layer from soil surface down to 10 depth were counted and the chemical analyses were performed on roots. In all aerial buds, there were relevant protection traits. The belowground organ is a sobole and the number of buds in its upper portion varied from 24 to 517 between individuals of both species. Phenolic compounds, fl avonoids, starch and other carbohydrates were detected in roots. The protection of aerial buds, the large number of belowground buds and the storing and protective compounds may have favored the resprouting of the species in the area.

Seasonally-dry environments of the Neotropics, such as the South American Chaco, exert selective pressures on vegetation through a pronounced water defi cit. We describe the underground system and leaf anatomy of three species of Asteraceae from the Brazilian portion of the Chaco (Pterocaulon purpurascens Malme, Wedelia trichostephia DC., and Pectis gardneri Baker), aiming to describe their structural and adaptive features using standard plant anatomy techniques. Pterocaulon purpurascens and W. trichostephia exhibited slightly thickened xylopodia, with gemmiferous character and self-grafted stem shoots; Pectis gardneri displayed a slightly-thickened tuberous root with storage substances. Longitudinal sequences of cells with highly thickened walls forming globular protrusions were found throughout the extension of the periderm of Pectis gardneri, while senescent trichomes were found in the periderm of W. trichostephia. Schyzogenous aerenchyma was found in P. purpurascens. Aquifer cells, composing vascular rays of secondary phloem and xylem, are reported for this species. Leaves of the three species are perennial and amphistomatic, with aquifer cells in a variety of tissues. Pectis gardneri exhibits a "Kranz-type" anatomy with lignifi ed bristles with stomata. Th e features described for the species play important role in water uptake and/or storage, which prevent excessive water loss during environmental or physiological stress periods.

Croton L. (Euphorbiaceae) is the second largest genus of the Euphorbiaceae s.l. family, which is composed of about 1,200 taxa. Several species are widely used medicinally in various parts of the world to treat cancer, digestive problems, skin diseases, malaria, ulcers, and obesity. The leaves and stems are sold as dehydrated fragments, or in powder form, and used in the preparation of teas and various types of formulations. The aim of this study was to accurately characterize the leaf anatomy of Croton bonplandianus Baill. and Croton gracilipes Baill. and to perform histochemical analysis of laticifers to provide subsidies for botanical certification. To accomplish this, leaf blade and petiole samples were fixed and prepared following standard techniques for scanning electron and light microscopy. Histochemical tests were carried out on sections to detect the compounds present in the secretions. Results showed neutral and acidic lipids, as well as phenolic compounds, in the latex. In addition, leaf anatomical structures of these two species were studied for specific identification of morphological characters and for quality assessment of these medicinal plants.

Question: The Cerrado represents the largest savanna of the Neotropics. Nowadays, this ecosystem is threatened by the afforestation by monocultures, such as Pinus spp., leading to serious damage to native herbaceous species. Afforestation of savanna ecosystems can affect their ability to regenerate naturally, which relies on different strategies, such as resprouting from below-ground bud-bearing organs. Therefore, we investigated the impact of ca. 50 years of Pinus elliottii plantations, compared to undisturbed areas of Cerrado savanna, estimating the bud bank size by counting buds on bud-bearing organs. We hypothesized that long-term P. elliottii plantations negatively affected the bud-bearing organs, leading to decreases in the bud bank. Location: Cerrado savanna areas and Pinus elliottii plantations, southeastern Brazil. Methods: Open savanna areas (hereafter Cerrado) and "P. elliottii plantations" were considered the vegetation types. Within each vegetation type, we designated three areas. In each area, we established 10 plots (1 m 2). For each plot, the bud bank was sampled from 5 cm above to 10 cm below ground level in subplots (0.25 m 2). We developed generalized linear mixed models (GLMM) for each response variable to test differences between both vegetation types. Results: The presence of the P. elliottii plantations for almost 50 years has led to massive reductions in the bud bank size and the number of bud-bearing organs, when compared to the Cerrado areas (p < 0.0001). Conclusions: The reduction in the below-ground bud-bearing organs density led to decreases in the bud bank and thus, loss of resilience in these areas. Regeneration in planting areas may not occur naturally after the removal of the plantations. Restoration of the herbaceous layer after P. elliottii removal will rely on the introduction of a new source of propagules through active interventions.

This study was carried out in a Cerrado (the largest savanna in the Neotropics) area where pine plantations, introduced in the 1970s, were removed by clear cutting of the trees and burning of the remaining material. After the removal and burning, some native shrub species resprouted. Since resprouting is dependent on buds that can be in the belowground bud-bearing (BBB) organs containing reserves, we selected three resprouting Myrtaceae species for analysis of morphology and anatomy of their BBB organs, to determine which compounds could be accumulated and to investigate the bud protection features. Standard histological techniques were used to analyse the BBB organs. The belowground bud bank at a depth of 10cm was determined. Nonstructural carbohydrates, total phenolics, and flavonoids were quantified on the roots. The large size of BBB organs suggest that these species were present before plantation establishment and survived plantation management treatments. All species produced a large number of axillary buds. All BBB organs exhibited significant lignification and stored starch and phenolic compounds in the parenchyma cells. The protective features and the storage of reserves associated with the bud-bank allowed the survival and subsequent resprouting of these species, contributing to the regeneration of this disturbed area.

Abstract.Associations between ants and plants may be described, in some cases, as mutualisms. Ants use plant structures as sites for nesting and in return they offer protection against herbivory. This paper reports for the first time the association between Pseudomyrmex acanthobius Emery nest in subterranean structures of Aspilia grazielae J.U.Santos, an endangered endemic plant species, in Corumbá, Pantanal domain. Additionally, this record reveals a new aspect of the ecological niche and extends the geographic distribution of P. acanthobius.Keywords: Aspilia grazielae; Interaction; Pseudomyrmicinae; Xylopodium. Primeiro Registro de Pseudomyrmex acanthobius Emery no Pantanal BrasileiroResumo. A associação entre formigas e plantas pode ser descrita em alguns casos como mutualismo. Estruturas de plantas, como locais de nidificação, atraem algumas espécies de formigas em troca da proteção anti-herbivoria. Este trabalho registra pela primeira vez a nidificação de Pseudomyrmex acanthobius Emery em estrutura subterrânea de Aspilia grazielae J.U.Santos, espécie endêmica e ameaçada de extinção na região de Corumbá, no domínio Pantanal. Adicionalmente, esse registro revela nova amplitude do nicho ecológico e amplia a distribuição geográfica prevista de P. acanthobius.

Question: How does seasonality affect the below-ground bud bank dynamics in open savannas from the Cerrado and the density of below-ground bud-bearing organs?As the Cerrado is subject to marked seasonality, many herbaceous plants may lose their above-ground biomass during the dry season, and regenerate it later in the rainy period through resprouting from below-ground buds. Herein, we tested the hypothesis that seasonality may directly affect bud bank dynamics and below-ground bud-bearing organs, with a larger bud bank size and higher densities of below-ground organs in the rainy season.Location: Open savannas of the Cerrado, southeastern Brazil. Methods:The bud bank was sampled in three open areas of the Cerrado. In each area, 10 plots were established, and, within each plot, the biomass was sampled to 10 cm below-ground level. In the lab, buds and below-ground organs were counted. We fitted generalized linear mixed models (GLMM) to test the differences in the bud bank and the below-ground organ densities between the dry and rainy seasons. Results:The bud bank size was smaller in the dry season. Buds found in the dry season suggest they were developed in the rainy season and remained dormant, not forming new shoots. Non-woody rhizomes of caespitose grasses were more abundant during the rainy season. Xylopodia and woody rhizome densities were not significantly affected by seasonality.Conclusions: Bud bank dynamics in the Cerrado is affected by seasonality. There is a decrease in bud bank density in the dry season, suggesting that buds were developed into new branches in the rainy season, but not all of them develop into new shoots in the same season. Thus, the bud bank evaluated in the dry season probably is formed by an accumulation of dormant preformed buds, highlighting the occurrence of a resprouting dynamic of native species of the Cerrado in the rainy season.

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