Publicação

As heras que ocorrem em Portugal são nativas ou introduzidas?

Detalhes bibliográficos
Resumo:	The Hedera genus belonging to the family Araliaceae currently has 18 accepted species, with distribution in temperate zones from Macaronesia to East Asia. Ivies or “heras”, the vernacular name by which they are known in Portugal, are climbing plants with the ability to form adventitious adhesive roots along the stems, being easily observed covering vertical surfaces such as walls in urbanized areas, or trees and rock formations in natural areas. The main goal of this dissertation is to identify and study the different taxa that occur in Portugal, both in nature (spontaneous) and in the garden (cultivated), using morphological, molecular, cytogenomic and biogeographic data. The research started by indiscriminately collecting samples of spontaneous and presumably cultivated Hedera, with the association of the exact collection coordinate for each sampled specimen. The specimens were analyzed under the morphological point of view, however, due to the high phenotypic plasticity/heterophily within the same taxa and sometimes within the same individual, the morphological analysis was focused mainly on the leaf trichomes, observed under the binocular magnifying glass and the scanning electron microscope (SEM). In addition, the degree of ploidy was inferred using flow cytometry and a molecular analysis based on nrDNA markers (ITS) was performed. Cytogenomic data were analyzed and related to 19 bioclimatic variables and altitude. The results of the present study revealed, based on trichome morphology and ploidy level, the occurrence of eight species of Hedera (H. algeriensis, H. azorica, H. canariensis, H. helix, H. hibernica, H. iberica, H. maderensis and H. maroccana) in Portugal, three of which are considered exotic species in this geographical scope (i.e., H. algeriensis, H. canariensis and H. maroccana). The ploidy study detected a variability from diploid to hexaploid among all taxa. The morphometric analysis of the leaves did not allow to distinguish the species or to detect any specific pattern. The molecular analysis confirmed the monophyly of the genus and the distinction between two main groups, the diploid species and the polyploid species. Cytogenomic results revealed that Hedera species range from 3.023 pg (H. maroccana) to 9.264 pg (H. maderensis); however, no solid patterns were detected when genome size was related to bioclimatic variables and altitude. However, further morphological, molecular and cytogenomic analyses and more fieldwork on the estimated distribution area of the genus Hedera will make it possible to reinforce the results obtained and identify more precisely which species of Hedera are present and, possibly, discover new species in Portugal, contributing to the preservation of the unique biodiversity of the Mediterranean basin, which is the largest centre of diversity of the genus.
Autores principais:	Ferreira, João Miguel Domingos da Cunha
Assunto:	Araliaceae morphometry ploidy Portugal trichomes morfometria ploidia tricomas
Ano:	2024
País:	Portugal
Tipo de documento:	dissertação de mestrado
Tipo de acesso:	acesso aberto
Instituição associada:	Universidade de Lisboa
Idioma:	português
Origem:	Repositório da Universidade de Lisboa