Morphological and anatomical characterization of the sporophyte of Trachypteris pinnata (Pteridaceae) in relation to xeromorphism
Hernández, Marcela Alicia; Omar Varela; Yanina Esther Fernández; María Gabriela Nadra. 2011. “Morphological and anatomical characterization of the sporophyte of Trachypteris pinnata (Pteridaceae) in relation to xeromorphism”. Lilloa 48 (2). Trachypteris (Pteridaceae) is fern genus with a disjunt distribution, represented in Argentina by Trachypteris pinnata (Hook. f.) C. Christ, which grows in the mountains in the Northwestern provinces. This research describes the morphology and anatomy of the sporophyte of Trachypteris pinnata, it shows ecologic data in reference to its abundance in Cerro Remate (Dpto. Pellegrini, Santiago del Estero) and compares its xeromorphic characters with those of other nine species of cheilanthoid ferns of Northwestern Argentina (Argyrochosma nivea var. nivea, Cheilanthes pilosa, C. bonariensis, C. buchtienii, C. notholaenoides, Pellaea ternifolia, Adiantopsis chlorophylla, Doryopteris lorentzii y D. concolor). The morphoanatomical analysis was carried out on fresh material and herbarium specimens of Trachypteris pinnata. Frond diaphanization, free hand sections and specific staining were applied. Stomatic size and frequency were calculated for 20 individuals. The morphoanatomic variables compared were the number of divisions of the frond, stomata size, density, percentage of sclerenquimatic tissue and foliar indument. The sporophyte of Trachypteris pinnata has dimorphic fronds, the sterile are sessile and form a rosette at the ground level, abaxial epidermis covered with scales and glandular trichomes, fertile frond erect, pinnate to pinnatifid with large petiole, with sporangia covering surface. Solenostelic rhizome, with scales of two types. Roots with primary diarch structure. T. pinnata inhabits slopes and hills, under cover of trees and shrubs, forming aggregations. Compared with other species of cheilanthoid ferns of NOA, Trachypteris pinnata exhibits the larger size of the stomata, the lowest percentage of sclerenchyma and unusual leaf coverage scales in contact with the ground. These features position the species among the lowest degree of xeromorphism, which is consistent with the shady conditions and high humidity of their habitat.
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| Format: | Digital revista |
| Language: | spa |
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Fundación Miguel Lillo
2011
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| Online Access: | http://www.lillo.org.ar/journals/index.php/lilloa/article/view/407 |
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