Características da micromorfologia e da anatomia foliar na taxonomia de nissolia jacq. (leguminosae, papilionoideae)
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Data
2021-05-31
Autores
Veiga, Vitória Floss da
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Universidade Estadual Paulista (Unesp)
Resumo
Nissolia Jacq., alocado no clado Adesmia (Leguminosae: Papilionoidae: Dalbergieae) é composto por 29 espécies distribuídas nas Américas e seu centro de distribuição é o México. A diversidade de estruturas secretoras, tais como epiderme glandular, idioblastos, canais e cavidades secretoras, além de tricomas glandulares é reportada nos gêneros que integram o clado Adesmia e a importância da combinação de caracteres da micromorfologia de superfície e da anatomia foliar como fontes adicionais em estudos taxonômicos tem sido ressaltado em Leguminosae. Neste sentido, foram analisadas a micromorfologia de superfície e a anatomia foliolar de representantes de Nissolia, a fim de reconhecer potenciais caracteres anatômicos úteis para taxonomia, corroborando na identificação dos táxons do gênero, além de apontar características associadas com o ambiente de ocorrência dos táxons. Adicionalmente, análises fenéticas (UPGMA e PCA) foram utilizadas para verificar padrões de variação anatomica dentre os táxons estudados. Para isso, amostras obtidas de exsicatas provenientes de coleções brasileiras e herbários estrangeiros foram processadas seguindo métodos usuais em microscopia de luz e eletrônica de varredura. Caraterísticas das superfícies foliolares como ceras epicuticulares em forma de placas, cutícula estriada, tricomas glandulares peltados, tricomas não-glandulares simples e estômatos com borda estomática espessa e elevada sobre a fenda estomática foram comuns a todos os táxons estudados. Do rol de 24 táxons estudados, 23 apresentaram folhas dorsiventrais, com um táxon isofacial; 17 foram hipoestomáticos e oito anfiestomáticos. Nervura principal proeminente na face dorsal, estômatos com cristas estomáticas e câmaras supra e subestomática desenvolvidas, epiderme unisseriada, células da epiderme bi-compartimentada e com idioblastos secretores de mucilagem; feixes vasculares colaterais e com extensão de bainha parenquimática em direção à superfície adaxial ou ambas às superfícies foliolares. Os idioblastos ocorreram em ambas as superfícies foliares, contudo foram mais abundantes na superfície adaxial, onde são mais volumosos, com paredes primárias espessas e formato variando de oval a cônico. As análises de agrupamento (UPGMA e PCA) efetuadas com base dos caracteres micromorfológicos e anatômicos, evidenciaram que as espécies de Nissolia se enquadram em dois grandes grupos e em cada um destes grupos mais dois agrupamentos foram estabelecidos. Caracteres úteis para delimitação desses grupos, foram número de camadas do parênquima paliçadico, posição dos tricomas e idioblastos na face abaxial. Em conclusão, alguns dos caracteres anatômicos da folha, por exemplo, tricomas nãoglandulares, estômatos com anel periestomático, celulas epidérmicas papiliformes e idioblastos secretores de mucilagem, constituem características principais para o agrupamento das espécies, enquanto a presença de ceras em placas, tricomas glandulares, cristais prismáticos de 12 oxalato de cálcio e extensão da bainha do feixe podem ser usados para delimitar táxons dentro do gênero
The genus Nissolia Jacq., classified within the clade Adesmia (Leguminosae: Papilionoidae: Dalbergieae) is composed of 29 species distributed throughout the Americas and the distribution center is Mexico. A great diversity of secretory structures, such as the glandular epidermis, idioblasts, secretory canals and cavities, alongside glandular trichomes, is reported in the genera that integrate the Adesmia clade. The importance of combining characters of surface micromorphology and leaf anatomy as additional sources for taxonomic research has been repeatedly highlighted while studying Leguminosae. In this sense, we analysed both the surface micromorphology and leaflet anatomy of representatives of Nissolia, in order to recognise anatomical characters potentially useful for taxonomy, to corroborate the identification of different taxa in the genus, as well as to point out characteristics associated with the environment where each species occur. Additionally, we used phenetic analysis (UPGMA and PCA) in order to verify variation patterns amongst the species whose anatomy we studied. For that, samples obtained from exsiccates from several Brazilian and foreign collections and herbariums were processed following usual methods in light and electron microscopy. Several characters on the foliole surface, such as plate-shaped epicuticular wax, striated cuticle, peltate glandular trichomes, simple non-glandular trichomes, and stomata with thickened stomatal border, elevated above the stomatal slit, were common to all studied taxa. From a variety of 24 studied taxa, 23 bore dorsiventral leaves, only one taxon being isofacial; 17 were hypostomatic and 8 amphistomatic. Prominent main rib on dorsal surface, stomata with well-developed stomatal ridges and sub and suprastomatal chambers, uniseriate epidermis, bicompartmented epidermal cells with mucilage-secreting idioblasts; collateral vascular bundles, with extensions of the parenchyma sheath towards either both surfaces, or only towards the adaxial one. Idioblasts occurred on both leaf surfaces, being more abundant on the adaxial surface, where they were larger in volume, with thick primary walls and presenting shapes varying from oval to conic. The cluster analyzes (UPGMA and PCA) carried out based on the micromorphological and anatomical characters, show that the Nissolia spicies fall into two large groups and in each of these groups two more groups were created. Useful characters for the delimitation of these groups were the number of layers of the palisade parenchyma, position of 13 the trichomes and idioblasts on the abaxial surface. In conclusion, some of the leaf anatomic characters – non-glandular trichomes, stomata with peristomatic rings, papilliform epidermal cells, and mucilage-secreting idioblasts, for instance – constitute the main characteristics for the classification and grouping of species, while the presence of plate-shaped wax, glandular trichomes, prismatic calcium oxalate crystals and extension of the bundle sheath, might be used to delimit taxa within the genus.
The genus Nissolia Jacq., classified within the clade Adesmia (Leguminosae: Papilionoidae: Dalbergieae) is composed of 29 species distributed throughout the Americas and the distribution center is Mexico. A great diversity of secretory structures, such as the glandular epidermis, idioblasts, secretory canals and cavities, alongside glandular trichomes, is reported in the genera that integrate the Adesmia clade. The importance of combining characters of surface micromorphology and leaf anatomy as additional sources for taxonomic research has been repeatedly highlighted while studying Leguminosae. In this sense, we analysed both the surface micromorphology and leaflet anatomy of representatives of Nissolia, in order to recognise anatomical characters potentially useful for taxonomy, to corroborate the identification of different taxa in the genus, as well as to point out characteristics associated with the environment where each species occur. Additionally, we used phenetic analysis (UPGMA and PCA) in order to verify variation patterns amongst the species whose anatomy we studied. For that, samples obtained from exsiccates from several Brazilian and foreign collections and herbariums were processed following usual methods in light and electron microscopy. Several characters on the foliole surface, such as plate-shaped epicuticular wax, striated cuticle, peltate glandular trichomes, simple non-glandular trichomes, and stomata with thickened stomatal border, elevated above the stomatal slit, were common to all studied taxa. From a variety of 24 studied taxa, 23 bore dorsiventral leaves, only one taxon being isofacial; 17 were hypostomatic and 8 amphistomatic. Prominent main rib on dorsal surface, stomata with well-developed stomatal ridges and sub and suprastomatal chambers, uniseriate epidermis, bicompartmented epidermal cells with mucilage-secreting idioblasts; collateral vascular bundles, with extensions of the parenchyma sheath towards either both surfaces, or only towards the adaxial one. Idioblasts occurred on both leaf surfaces, being more abundant on the adaxial surface, where they were larger in volume, with thick primary walls and presenting shapes varying from oval to conic. The cluster analyzes (UPGMA and PCA) carried out based on the micromorphological and anatomical characters, show that the Nissolia spicies fall into two large groups and in each of these groups two more groups were created. Useful characters for the delimitation of these groups were the number of layers of the palisade parenchyma, position of 13 the trichomes and idioblasts on the abaxial surface. In conclusion, some of the leaf anatomic characters – non-glandular trichomes, stomata with peristomatic rings, papilliform epidermal cells, and mucilage-secreting idioblasts, for instance – constitute the main characteristics for the classification and grouping of species, while the presence of plate-shaped wax, glandular trichomes, prismatic calcium oxalate crystals and extension of the bundle sheath, might be used to delimit taxa within the genus.
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Palavras-chave
Cera epicuticular, Estômatos, Idioblasto de mucilagem, Superfície foliar, Tricoma glandular, Tricoma não-glandular, Epicuticular wax, Stomata, Mucilage idioblasts, Leaf surface, Glandular trichome, Non-glandular trichome