Leaf and stem micromorphology of Jacquemontia evolvuloides (Moric.) Meisn. (Convolvulaceae) populations: New insights for taxonomic classification using light and scanning electron microscopy.

Morphoanatomical studies can provide useful and relevant information to support taxonomic groupings. Jacquemontia evolvuloides shows great morphological variability, which has led to numerous taxonomic classifications. To determine if anatomical characters can be used to recognize operational taxonomic units within populations of that species, we analyzed the leaves and stems of 22 populations using light and scanning electron microscopy. The variability of the analyzed characters allowed the grouping of these populations into five morphotypes. The presence of paracytic stomata, laticiferous canals, and stellate trichomes can be considered diagnostic characters of J. evolvuloides. The presence and types of epicuticular waxes, as well as a layer similar to palisade parenchyma in the petioles and stems, the classifications of glandular trichomes, and new types of stomata (anomocytic, anomotetracytic, and brachyparatetracytic) are reported here for the first time for Jacquemontia. The results discussed here help clarify the classification of this species complex and contribute to the taxonomy of Jacquemontia-a genus that has historically been difficult to define due to its wide morphological variation at the species level. RESEARCH HIGHLIGHTS: Seven types of epicuticular waxes were identified among J. evolvuloides specimens: granules, threads, entire platelets, coiled rodlets, fissured layers, membranous platelets, and tubules. Six types of trichomes were observed among J. evolvuloides populations: stellate, malpighiaceous, sessile peltate glandular, short pedunculate glandular, stipitate-glandular, and capitate glandular. We observed that six populations of Jacquemontia evolvuloides located in the Brazilian Caatinga domain have unprecedented sessile peltate trichomes restricted to the main leaf midrib, which were only observed under light microscopy.

Leaf surface traits related to differential particle adsorption - A case study of two tropical legumes.

We aimed to test a set of epidermal traits in two legume species with contrasting chemical, physical, and micromorphological leaf-surface features to assess which ones would determine higher PM retention. For that, we performed a biomonitoring study in southeastern Brazil at the Steel Valley Metropolitan Region, where there is predominance of steel industry and one of the largest vehicle fleets in the country. A reference station was installed at a neighboring park. We evaluated leaf-surface roughness at two hierarchical levels, leaf wettability, epidermal-cell anticlinal-wall undulation, epidermal-cell perimeter, and the micromorphology and chemical composition of epicuticular waxes. Particle retention was significantly higher in Paubrasilia echinata than in Libidibia ferrea var. leiostachya, the former of which has lower roughness given by both the epidermal tissue (macro-roughness; 0.6 vs 2.6 µm) and epicuticular waxes (micro-roughness; 68 vs 220 nm), higher leaf wettability (82° vs 143°), lower epidermal-cell undulation index (1.2 vs 1.8), lower epidermal-cell perimeter (93 vs 146 µm), wax deposition in the form of a smooth layer (as opposed to densely aggregated rosettes of vertical platelets), and more polar wax chemical constitution (68% vs 47% of polar compounds). While all of the assessed traits contributed to particle retention, canonical loadings revealed that macro-roughness was the trait that contributed the most to the retention of PM2.5 (ca = 1.47; r = -0.56), PM10 (ca = 1.08; r = -0.61), PM100 (ca = -4.95; r = -0.39) and TSP (ca = 0.98; r = -0.62), although this trait was shown by factor analysis to be secondary in distinguishing between species (0.92 contribution to the second axis). Our findings shed new light on the criteria that should be considered when selecting species for green infrastructure aiming to reduce urban air pollution, as well as on novel possibilities for PM biomonitoring in the tropics.

Leaf epidermal characteristics of Cissampelos L. (Menispermaceae) species from Northeastern Brazil.

The morphological similarities among the species of Cissampelos are remarkable and the difficult to distinguish them as well. This article presents a comparative anatomical study of the leaves of common Northeastern Brazilian species of Cissampelos, carried out using light and scanning electron microscopy. The leaf epidermal was studied to obtain data on epidermal characteristics and to evaluate their taxonomic significance. As results, some micromorphological characters on the leaf epidermal like the cuticular waxes, the presence of papillae in epidermis and nonglandular trichomes, the anticlinal walls epidermal cells, the distribution, density and type of trichomes, and also the type and distribution of epicuticular wax proved to be the most useful characteristics to distinguish the species in taxonomic studies.

Use of palmae wax hydrocarbon fractions as chemotaxonomical markers in Butia and Syagrus / Uso de frações de hidrocarbonetos de palmeiras como marcadores quimiotaxonômicos em Butia e Syagrus

The wax hydrocarbon fractions of native Butia and Syagrus species collected from Palms in different regions of the of Rio Grande do Sul state (Brazil) and in Rocha (Uruguay) were analyzed to evaluate their potential as chemotaxonomic markers. The wax was extracted with chloroform and the resulting wax was fractionated by preparative TLC. The hydrocarbon fractions were analyzed by GC-MS. Statistical analyses were completed with the Statistica 5.0 program. The total crude wax yields averaged 0.31% w.w–1 dried leaves for Butia samples and 0.28% for Syagrus samples. The linear hydrocarbons represented on average 15% of the total waxes in the case of Butia samples and 13.7% in Syagrus samples. Hentriacontane and triacontane were the main components of all samples. The comparison of the means showed significant differences among Butia and Syagrus samples, and amongst Butia samples collected in different localities. In the case of the Syagrus collections no consistent groupings could be made. In the case of Butia samples the formation of three groupings could be observed, which were consistent with the species described for their geographical distribution. These results are discussed in the paper.

Frações de hidrocarbonetos das ceras de espécies nativas de Butia e Syagrus coletadas de palmeiras em diferentes regiões do Rio Grande do Sul (Brasil) e em Rocha (Uruguai) foram analisadas para avaliar o seu potencial como marcadores quiomiotaxonômicos. As ceras foram extraídas com clorofórmio e fracionadas por TLC preparativo. As frações de hidrocarbonetos foram analisadas por CG-EM. As análises estatísticas foram realizadas com auxílio do programa Statistica 5.0. O rendimento total de cera das folhas secas foi de 0,31% g.g–1 para as amostras de Butia e de 0,28% para Syagrus. Os hidrocarbonetos lineares representaram em média 15 e 13% do total das ceras para Butia e Syagrus, respectivamente. Hentriacontano e triacontano foram os compostos majoritários em todas as amostras. A comparação de médias mostrou diferenças significativas entre as amostras de Butia e Syagrus e entre as amostras de Butia coletadas em diferentes localidades. As amostras de Syagrus não formaram agrupamentos relacionados com os locais de coleta. Já no caso de Butia, três agrupamentos puderam ser observados e são consistentes com a distribuição geográfica desta espécie. Estes resultados são discutidos no trabalho.

Use of palmae wax hydrocarbon fractions as chemotaxonomical markers in Butia and Syagrus

The wax hydrocarbon fractions of native Butia and Syagrus species collected from Palms in different regions of the of Rio Grande do Sul state (Brazil) and in Rocha (Uruguay) were analyzed to evaluate their potential as chemotaxonomic markers. The wax was extracted with chloroform and the resulting wax was fractionated by preparative TLC. The hydrocarbon fractions were analyzed by GC-MS. Statistical analyses were completed with the Statistica 5.0 program. The total crude wax yields averaged 0.31% w.w-1 dried leaves for Butia samples and 0.28% for Syagrus samples. The linear hydrocarbons represented on average 15% of the total waxes in the case of Butia samples and 13.7% in Syagrus samples. Hentriacontane and triacontane were the main components of all samples. The comparison of the means showed significant differences among Butia and Syagrus samples, and amongst Butia samples collected in different localities. In the case of the Syagrus collections no consistent groupings could be made. In the case of Butia samples the formation of three groupings could be observed, which were consistent with the species described for their geographical distribution. These results are discussed in the paper.

Frações de hidrocarbonetos das ceras de espécies nativas de Butia e Syagrus coletadas de palmeiras em diferentes regiões do Rio Grande do Sul (Brasil) e em Rocha (Uruguai) foram analisadas para avaliar o seu potencial como marcadores quiomiotaxonômicos. As ceras foram extraídas com clorofórmio e fracionadas por TLC preparativo. As frações de hidrocarbonetos foram analisadas por CG-EM. As análises estatísticas foram realizadas com auxílio do programa Statistica 5.0. O rendimento total de cera das folhas secas foi de 0,31% g.g-1 para as amostras de Butia e de 0,28% para Syagrus. Os hidrocarbonetos lineares representaram em média 15 e 13% do total das ceras para Butia e Syagrus, respectivamente. Hentriacontano e triacontano foram os compostos majoritários em todas as amostras. A comparação de médias mostrou diferenças significativas entre as amostras de Butia e Syagrus e entre as amostras de Butia coletadas em diferentes localidades. As amostras de Syagrus não formaram agrupamentos relacionados com os locais de coleta. Já no caso de Butia, três agrupamentos puderam ser observados e são consistentes com a distribuição geográfica desta espécie. Estes resultados são discutidos no trabalho.

Patterns of leaf epicuticular waxes in species of Clusia: taxonomical implications

El género Clusia L. (Clusiaceae) comprende unas 300 especies que ocurren desde México y el sur de EEUU hasta Bolivia y el sur de Brasil. Entre ellas se incluyen árboles y arbustos, hemiepifitas, epifitas y lianas. El análisis taxonómico del género se dificulta por la pobre preservación de las flores al ser secadas. Este trabajo explora la composición de ceras epicuticulares para caracterizar especies mediante marcadores químicos. Se analizó la composición del extracto obtenido de seis especies mediante lavado de la superficie foliar con hexano. Las especies pudieron separarse en base a la proporción de alcanos, >90% del total en Clusia rosea, C. orthoneura y C. minor, a la presencia de los triterpenos a-amirina y lupeol en C. multiflora, y de friedelina y taraxerol, conjuntamente con C33 y C35 en C. grandiflora y C. schomburgkiana. Los resultados sugieren que la proporción de alcanos y triterpenoides de ceras epicuticulares tiene importancia taxonómica y puede ser utilizada para separar especies o secciones infragenéricas.

The genus Clusia L. (Clusiaceae) encompasses ca. 300 species and occurs from southern USA and Mexico, to southern Brazil and Bolivia. It includes free-standing trees and shrubs, hemiepiphytes, epiphytes, and lianas. Taxonomic analysis of this genus is difficult because of the poor preservation of floral material after drying. This work explores the composition of epicuticular waxes in order to allow characterization, at the species level, using chemical markers. The six species analyzed could be separated using the relative quantity of hexane-soluble compounds extractable from the leaf surface, which amount to >90% in Clusia rosea, C. orthoneura, and C. minor, the presence of the triterpenes a-amyrin and lupeol in C. multiflora, and of friedelin and taraxerol, together with C33 and C35, in C. grandiflora and C. schomburgkiana. The results suggest that the relative proportions of alkanes and triterpenoids in epicuticular waxes may have taxonomic significance for separating species or infrageneric sections.

O gênero Clusia L. (Clusiaceae) compreende umas 300 espécies que ocorrem desde México e o sul dos EE.UU. até Bolívia e o sul do Brasil. Entre elas se incluem árvores e arbustos, hemiepífitas, epífitas e lianas. A análise taxonômica do gênero se dificulta pela pobre preservação das flores ao ser secadas. Este trabalho explora a composição de ceras epicuticulares para caracterizar espécies mediante marcadores químicos. Se analisou a composição do extrato obtido de seis espécies mediante lavado da superfície foliar com hexano. As espécies puderam separar-se em base à proporção de alcanos, >90% do total em Clusia rosea, C. orthoneura e C. minor, à presença dos triterpenos a-amirina e lupeol em C. multiflora, e de friedelina e taraxerol, conjuntamente com C33 e C35 em C. grandiflora e C. schomburgkiana. Os resultados sugerem que a proporção de alcanos e triterpenóides de ceras epicuticulares tem importância taxonômica e pode ser utilizada para separar espécies ou seções infragenéricas.