Anatomia foliar de espécies de Poaceae (Poales) e sua importância na sistemática e filogenia
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Data
2016-12-07
Autores
Leandro, Thales Henrique Dias [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Buscando levantar caracteres da lâmina foliar que auxiliem na sistemática e filogenia de Poaceae foram realizados estudos anatômicos e ultraestruturais. Em Bambusoideae, caracteres como papilas dispersas na face abaxial e células buliformes organizadas paralelamente são úteis para o reconhecimento de Olyreae; enquanto papilas organizadas em colunas centrais e células buliformes em forma de leque são úteis para o reconhecimento de Bambuseae. Em Bambuseae, fibras intercostais e nervura central simples são caracteres diagnósticos de Arthrostylidiinae; enquanto complexo estomático portando duas papilas por célula subsidiária e nervura central complexa são caracteres diagnósticos de Chusqueinae. O levantamento de caracteres da lâmina foliar de espécies de Chusquea pertencentes ao clado II “Chusquea ramosissima” indica estruturas úteis para sua delimitação, tais como: complexo estomático, tipo de tricomas, tipo e arranjo de células silicosas, e tipo e número de camadas de células invaginantes; bem como sustenta o reconhecimento deste clado e de uma nova espécie para a Bolívia. O estudo do desenvolvimento foliar com ênfase nas células fusoides mostra sua origem proveniente do meristema fundamental e que a cavidade observada em secções transversais de lâminas foliares maduras é resultado do colapso de várias células fusoides. A origem proveniente do meristema fundamental é confirmada para toda a família e homologias são observadas dentre diferentes tipos de células parenquimáticas do mesofilo. O estudo ainda sugere que células fusoides evoluíram das células incolores observadas em Joinvilleaceae. São fornecidas descrições anatômicas gerais da lâmina foliar para as 12 subfamílias reconhecidas para Poaceae, bem como a definição estrutural e a reavalição da importância de alguns caracteres na sistemática do grupo.
To seek leaf blade features useful for systematics and phylogenetics of Poaceae, anatomical and ultrastructural studies were carried out. Within Bambusoideae, features such as papillae scattered on the abaxial surface and parallel-sided arrays of bulliform cells are useful for recognizing Olyreae; whereas centrally organized papillae and fan-shaped arrays of bulliform cells are useful for recognizing Bambuseae. Within Bambuseae, intercostal fibers and simple midrib are diagnostic features of Arthrostylidiinae; whereas stomatal apparatus bearing two papillae per subsidiary cell and complex midrib are diagnostic features of Chusqueinae. The survey of leaf blade anatomical features of Chusquea species that comprise the clade II “Chusquea ramosissima” shows structures for delimiting species, such as: stomatal apparatus, type of trichomes, type and arrangement of silica bodies, and type and number of layers of arm cells; as well as supports the recognition of this clade and of a new species from Bolivia. The foliar developmental study with emphasis on fusoid cells shows their meristematic origin from the ground meristem and that the cavity as seen in cross section in mature leaves is resulting from the collapse of several fusoid cells. Their origin from the ground meristem is confirmed throughout the family and homologies are observed among different types of mesophyll parenchymatous cells. The study also suggests that fusoid cells evolved from colourless cells of Joinvilleaceae. General leaf blade anatomical descriptions of the 12 recognized subfamilies of Poaceae are provided, as well as structural definition and reevaluation of the relevance of anatomical features in grass systematics.
To seek leaf blade features useful for systematics and phylogenetics of Poaceae, anatomical and ultrastructural studies were carried out. Within Bambusoideae, features such as papillae scattered on the abaxial surface and parallel-sided arrays of bulliform cells are useful for recognizing Olyreae; whereas centrally organized papillae and fan-shaped arrays of bulliform cells are useful for recognizing Bambuseae. Within Bambuseae, intercostal fibers and simple midrib are diagnostic features of Arthrostylidiinae; whereas stomatal apparatus bearing two papillae per subsidiary cell and complex midrib are diagnostic features of Chusqueinae. The survey of leaf blade anatomical features of Chusquea species that comprise the clade II “Chusquea ramosissima” shows structures for delimiting species, such as: stomatal apparatus, type of trichomes, type and arrangement of silica bodies, and type and number of layers of arm cells; as well as supports the recognition of this clade and of a new species from Bolivia. The foliar developmental study with emphasis on fusoid cells shows their meristematic origin from the ground meristem and that the cavity as seen in cross section in mature leaves is resulting from the collapse of several fusoid cells. Their origin from the ground meristem is confirmed throughout the family and homologies are observed among different types of mesophyll parenchymatous cells. The study also suggests that fusoid cells evolved from colourless cells of Joinvilleaceae. General leaf blade anatomical descriptions of the 12 recognized subfamilies of Poaceae are provided, as well as structural definition and reevaluation of the relevance of anatomical features in grass systematics.
Descrição
Palavras-chave
Anatomia, Clado BOP, Clado PACMAD, Clado Graminídeo, Folha, Gramíneas, Linhagens basais, Ontogenia, Anatomy, Early-diverging lineages, BOP clade, Graminid clade, Leaf, Grasses, Ontogeny, PACMAD clade