Aline Bertolosi Bombo

Anatomy and essential oils from aerial organs in three species of Aldama (Asteraceae–Heliantheae) that have a difficult delimitation

Recently, molecular analysis caused the South American Viguiera Kunth species to be transferred to Aldama La Llave. However, the circumscription has not been established for certain of the South American species, including Aldama filifolia (Sch.Bip. ex Baker) E.E.Schill. & Panero, A. linearifolia (Chodat) E.E.Schill. & Panero and A. trichophylla (Dusen) Magenta (comb. nov.), which had previously been treated as synonyms because of their high similarity. Therefore, the present study aimed to evaluate the anatomy of the aerial organs, and the yield and chemical composition of the essential oils from these three species, to determine the differences among them and thereby assist in species distinction. The anatomical analysis identified characteristics unique to each species, which are primarily related to the position and occurrence of secretory structures. Histochemical analysis demonstrated that the glandular trichomes and the canals secrete lipophilic substances, which are characterised by the presence of essential oils. The analysis of these essential oils identified monoterpenes as their major constituent and allowed for the recognition of chemical markers for each species. The anatomical and chemical characteristics identified by the present study confirmed that the studied samples belong to three distinct taxa.

Anatomy and essential oil composition of the underground systems of three species of Aldama La Llave (Asteraceae)1

Abstract The species chosen in this study were Aldama filifolia (Sch. Bip. ex Baker) E.E.Schill. & Panero, A. linearifolia (Chodat) E.E.Schill. & Panero, and A. trichophylla (Dusén) Magenta, which are morphologically very similar. Their representatives are perennial, cespitose herbs with an odoriferous resin and a xylopodium with tuberous adventitious roots. These species are from Cerrado areas and present seasonality of development. The aim of the present study was to provide anatomical features of the underground system of the aforementioned species and try to explain certain aspects of their environmental adaptation. Some of the structural characteristics observed in the Aldama species are new for the Asteraceae family, such as a secondary protective tissue similar to storied cork, the variation of cambial activity in A. filifolia, and the tuberisation process by division of the medullary parenchyma cells. The essential oil composition of the xylopodia and roots showed some differences among the species and allowed the identification of some compounds with biological properties. The underground system, which has gemmiferous ability and tuberised roots able to store inulin-type fructans, is related to the seasonality of growth and the adaptation of such plants to the environmental conditions of their habitat.

New approaches to underground systems in Brazilian Smilax species (Smilacaceae).

Abstract New approaches to underground systems in Brazilian Smilax species (Smilacaceae). Scientific studies show that the watery extract of the thickened underground stem and its adventitious roots of the genus Smilax can act as a therapeutic agent in immunoinflammatory disorders, such as rheumatic arthritis. Brazilians have used this genus of plants in folk medicine, however it is very hard to identify these species, since the morphology of the underground systems is very similar in this group. For better identification of those systems, we studied six species of Smilax L. (S. brasiliensis, S. campestris, S. cissoides, S. goyazana, S. oblongifolia and S. rufescens), collected in different regions of Brazil with different physiognomies and soil characteristics. The main purpose is to describe the morpho-anatomy of the underground systems and to analyze if their structure depends on environmental conditions. The underground stem (rhizophore) is of brown color and it is knotty, massive, slender (S. rufescens) or tuberous (S. brasiliensis, S. campestris, S. cissoides, S. goyazana and S. oblongifolia). The tuberization is a result of primary thickened meristem (PTM) activity. The color and thickness of the adventitious roots change during development because the epidermis and outer cortex are disposed of, so the inner cortex becomes the new covering tissue with lignified and dark color cells. There are differences in starch grain shapes in mature roots. The chemical attributes of the soil are very similar in all studied environments and, even when soil characteristics varied, all the species underground system was distributed close to the soil surface (10 to 15 cm deep). The species exhibited clonal growth hence their underground system functions as storage structures and the axillary buds can sprout into new stems. Only Smilax rufescens, collected in sandy soil of Restinga, has vegetative dispersal due to the runners.

Capitate glandular trichomes in Aldama discolor (Heliantheae – Asteraceae): morphology, metabolite profile and sesquiterpene biosynthesis

The capitate glandular trichome is the most common type described in Asteraceae species. It is known for its ability to produce various plant metabolites of ecological and economic importance, among which sesquiterpene lactones are predominant. In this paper, we applied microscopy, phytochemical and molecular genetics techniques to characterise the capitate glandular trichome in Aldama discolor, a native Brazilian species of Asteraceae, with pharmacological potential. It was found that formation of trichomes on leaf primordia of germinating seeds starts between 24xa0h and 48xa0h after radicle growth indicates germination. The start of metabolic activity of trichomes was indicated by separation of the cuticle from the cell wall of secretory cells at the trichome tip after 72xa0h. This coincided with the accumulation of budlein A, the major sesquiterpene lactone of A.xa0discolor capitate glandular trichomes, in extracts of leaf primordia after 96xa0h. In the same timeframe of 72-96xa0h post-germination, gene expression studies showed up-regulation of the putative germacrene A synthase (pGAS2) and putative germacrene A oxidase (pGAO) of A.xa0discolor in the transcriptome of these samples, indicating the start of sesquiterpene lactone biosynthesis. Sequencing of the two genes revealed high similarity to HaGAS and HaGAO from sunflower, which shows that key steps of this pathway are highly conserved. The processes of trichome differentiation, metabolic activity and genetic regulation in A.xa0discolor and in sunflower appear to be typical for other species of the subtribe Helianthinae.

Solving taxonomic problems within the Aldama genus based on anatomical characters

Anatomical characteristics have proved to be an invaluable asset for supporting taxonomic studies on different plant families, such as Asteraceae. Anatomical features can also help clarify taxonomical problems in the Aldama La Llave genus, especially among Brazilian representatives. The present study focussed on Aldama bakeriana, A. discolor, A. grandiflora and A. squalida. These species were chosen because they are difficult to identify taxonomically if the specimens have no flowers, they have biological and pharmacological potential and they are representative species from key morphological groups in the Aldama genus and could help in future taxonomical investigations. Aerial and underground vegetative organs from the four species were described herein for the first time and a comparative analysis was performed to highlight the unique features of each species and determine whether these species can be differentiated in terms of anatomy. All four species analysed were anatomically very similar. However, they could be differentiated on the basis of the set of anatomical features described for each species. On the basis of our findings, we concluded that anatomy is able to provide data to assist with the taxonomic problems within the four species analysed herein. The results also corroborated other studies on the Aldama genus.

Aerial stem and leaf morphoanatomy of some species of Smilax

This study aimed to describe the morphoanatomy of the aerial vegetative organs of seven Smilax species, used in Brazilian folk medicine. Samples of leaves and stems were fixed with FAA 50, embedded in historesin, sectioned on a rotary microtome, stained and mounted in synthetic resin. Cuticle ornamentation was analyzed with standard scanning electron microscopy. In the frontal view, the walls of the adaxial epidermis are straight in S. brasiliensis, S. cissoides, S. goyazana and sinuous in the other species. The walls of the epidermis on the abaxial surface are straight in S. brasiliensis, S. goyazana, S. rufescens, sinuous in S. campestris, S. fluminensis, S. oblongifolia, and wavy in S. cissoides. The stomata are paracytic in S. brasiliensis, S. goyazana, S. oblongifolia, and S. rufescens, anomocytic in S. cissoides, S. campestris; anisocytic and paracytic in S. fluminensis. The midrib has three vascular bundles that are individually wrapped by lignified cells in S. brasiliensis, S. cissoides, and S. fluminensis. In the other, the three vascular bundles are surrounded by a single lignified sheath. In the stems the vascular cylinder is surrounded by a sclerenchymatous ring with the exception of Smilax fluminensis, which has a starch sheath and internal layers of thin-walled cells.

Can climate and soil conditions change the morpho-anatomy among individuals from different localities? A case study in Aldama grandiflora (Asteraceae)

Vegetative aerial organs are considerably more exposed to environmental conditions and can reflect the specific adaptations of plants to their local environment. Aldama grandiflora species are known to be widely distributed in Brazil; therefore, individuals from different populations of this species are thought to be exposed to different abiotic and biotic conditions. Several anatomical studies conducted on Brazilian Aldama species have mainly focused on the qualitative anatomical characters or traits of these species, but not on their quantitative traits. In this study, we evaluated whether climate and soil conditions can change the morphometry among individuals of A. grandiflora collected from six sites in the Goiás State, Brazil, by assessing their anatomical characters. Further, soil sampling was performed, and climate data were collected from all the six sites. The analysis indicated few statistical differences among the populations evaluated, showing that A. grandiflora presented consistent leaf and stem anatomical characteristics. The small morpho-anatomical differences found among individuals of the different populations evaluated, reflected the soil conditions in which these populations were grown. Therefore, environmental factors have a significant influence on the morpho-anatomy of Aldama grandiflora.

Leaf and stem anatomy and essential oil composition of four Brazilian Aldama species (Asteraceae) and their taxonomic significance

Aldama La Llave is one of several Asteraceae genera that pose phylogenetic problems. The close similarity between species, as well as the inconsistencies found in the most recent phylogenetic analysis, shows that new data are needed to help delimit group species. Aldama anchusifolia (DC) E.E.Schill. & Panero, Aldama megapotamica (Malme) Magenta & Pirani, Aldama nudibasilaris (S.F.Blake) E.E.Schill. & Panero and Aldama pilosa (Baker) E.E.Schill. & Panero are difficult to identify because they are very closely related. Therefore, the aim of this study was to detect anatomical and phytochemical characteristics to help elucidate phylogenetic issues raised by Aldama. Aerial vegetative organs were prepared using the standard histological techniques. Essential oils were obtained by hydrodistillation, and their components identified using a gas chromatograph coupled to a mass spectrometer and flame ionization detector. Each species presented a set of unique leaf and stem anatomical features. The front view of the epidermal cell walls in the leaves, the presence of secretory ducts in the phloem and medulla sclerification in the stems proved useful in delimiting these species. The essential oils were characterized by the predominance of sesquiterpenes such as t-caryophyllene, germacrene D and bicyclogermacrene. Some unique constituents in each species were also identified as potential chemical markers.

Seasonal variation of the essential oil from two Brazilian native Aldama La Llave (Asteraceae) species

Aldama arenaria and A. robusta are morphologically similar aromatic species that have seasonal development. The yield and chemical composition of essential oils from aerial and underground vegetative organs of these species were compared to verify the production of volatile metabolites in flowering and dormant phases of development and to identify if there are unique compounds for either species. The major compound in the essential oils from A. arenaria leaves was palustrol (16.22%) and for aerial stems was limonene (15.3%), whereas limonene (11.16%) and α-pinene (19.64%) were the major compounds for leaves and aerial stems from A. robusta, respectively. The major compound for the underground organs was α-pinene, in both species and phenological stages. High amounts of diterpenes were found especially for A. arenaria essential oils. Each analyzed species presented unique compounds, which can provide a characteristic chemical profile for both species helping to solve their taxonomic problems. This study characterized for the first time the yield and essential oil composition of A. arenaria and A. robusta, which have medicinal potential, and some of the compounds in their essential oils are unique to each one and may be useful in helping the correct identification of them.