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Abstract Detail

Developmental and Structural Section

Filartiga, Arinawa Liz [1], Appezzato-da-Glória, Beatriz [1].

Comparative anatomy of the leaves and stems of three Brazilian species of Asteraceae.

Recent molecular analysis caused the South American species of Viguiera to be transferred to the genus Aldama. However, there are some species combinations missing, for example, Viguiera megapotamica Malme, and circumscription has not been established for certain of the South American Aldama species, including Aldama anchusifolia (D. C.) E. E. Schill. & Panero and A. nudibasilaris (S. F. Blake) E. E. Schill. & Panero, which have high morphological similarity and apparently can produce hybrids. Therefore, the present study aimed to evaluate the anatomy of aerial vegetative organs from these three species, to determine the differences among the species and thereby assist in species distinction. Samples were collected from three different populations located on roadsides in the states of Rio Grande do Sul and Minas Gerais, Brazil. Fully expanded leaves and stems of different diameters were processed according to usual techniques in plant anatomy. It was found differences among the studied species. In paradermal sections of the leaves, the outline of the cell wall is straight only in V. megapotamica; stomata are found on both epidermis except for A. nudibasilaris that is hypostomatic. Mesophyll is dorsiventral, except for V. megapotamica that exhibit homogeneous mesophyll. The position of the ducts on the midrib is considered a conservative characteristic, able to define species. However, comparing the populations analyzed here there are detected variations related to the number and position of these ducts. Secretory ducts in the phloem of the midrib are observed only in A. nudibasilaris. The anatomy of the stem is characterized by uniseriate epidermis, followed by collenchyma and parenchyma. The endodermis has Casparian strips and eventually starch grains. Secretory ducts are observed in the cortex of all species. The vascular cylinder of A. nudibasilaris has ducts in primary phloem. The pith has parenchyma cells and there are ducts near to the primary xylem. During the development of the stem, the epidermis ruptures and is replaced by cells with suberized walls formed from periclinal divisions of subepidermal cells. Some cells of the cortex undergo lignification. The cambium form vascular tissues and parenchyma rays. All studied species exhibit secretory ducts in the secondary phloem. The pith expands due to division and cell elongation, except for V. megapotamica in which the pith becomes lignified. The differences in the anatomy of leaves and stem described here are useful for species differentiation.

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Asteraceae Project: Morphoanatomical, metabolomics and molecular studies

1 - University of Sao Paulo, Biological Sciences , 11 Padua Dias Avenue, Piracicaba, SP, 13418900, Brasil

Aldama anchusifolia
Aldama nudibasilaris
Viguiera megapotamica.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PDS004
Abstract ID:132
Candidate for Awards:None

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