Person:
Raggio Quílez, José

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First Name
José
Last Name
Raggio Quílez
URI
https://hdl.handle.net/20.500.14352/77615
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Farmacia
Department
Farmacología, Farmacognosia y Botánica
Area
Botánica
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2011 - 20122
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Author: Ascaso, Carmen × Has files: true ×

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    Extreme phenotypic variation in Cetraria aculeata (lichenized Ascomycota): adaptation or incidental modification?
    (Annals of Botany, 2012) Pérez-Ortega, Sergio; Fernández-Mendoza, Fernando; Raggio Quílez, José; Vivas, Mercedes; Ascaso, Carmen; García Sancho, Leopoldo; Printzen, Christian; Ríos, Asunción de los
    Phenotypic variability is a successful strategy in lichens for colonizing different habitats. Vagrancy has been reported as a specific adaptation for lichens living in steppe habitats around the world. Among the facultatively vagrant species, the cosmopolitan Cetraria aculeata apparently forms extremely modified vagrant thalli in steppe habitats of Central Spain. The aim of this study was to investigate whether these changes are phenotypic plasticity (a single genotype producing different phenotypes), by characterizing the anatomical and ultrastructural changes observed in vagrant morphs, and measuring differences in ecophysiological performance. Methods Specimens of vagrant and attached populations of C. aculeata were collected on the steppes of Central Spain. The fungal internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GPD) and the large sub-unit of the mitochondrial ribosomal DNA (mtLSUm), and the algal ITS and actin were studied within a population genetics framework. Semi-thin and ultrathin sections were analysed by means of optical, scanning electron and transmission electron microscopy. Gas exchange and chlorophyll fluorescence were used to compare the physiological performance of both morphs. Key Results and Conclusions Vagrant and attached morphs share multilocus haplotypes which may indicate that they belong to the same species in spite of their completely different anatomy. However, differentiation tests suggested that vagrant specimens do not represent a random sub-set of the surrounding population. The morphological differences were related to anatomical and ultrastructural differences. Large intercalary growth rates of thalli after the loss of the basal–apical thallus polarity may be the cause of the increased growth shown by vagrant specimens. The anatomical and morphological changes lead to greater duration of ecophysiological activity in vagrant specimens. Although the anatomical and physiological changes could be chance effects, the genetic differentiation between vagrant and attached sub-populations and the higher biomass of the former show fitness effects and adaptation to dry environmental conditions in steppe habitats.
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    Anatomical, morphological and ecophysiological strategies in Placopsis pycnotheca (lichenized fungi, Ascomycota) allowing rapid colonization of recently deglaciated soils
    (Flora, 2011) Ríos, Asunción De los; Raggio Quílez, José; Pérez-Ortega, Sergio; Vivas, Mercedes; Pintado Valverde, Ana; Green, Thomas George Allan; Ascaso, Carmen; García Sancho, Leopoldo
    The green algal lichen Placopsis pycnotheca was identified at Pia and Marinelli glaciers (Isla Grande of Tierra de Fuego, Chile) as a primary colonizer of bare soil in areas close to the front of the glacier or around small ponds created after glacier retreatment. Electron microscopy study showed that P. pycnotheca formed a thick hypothallus within which hyphae and their extracellular polymeric substances bind numerous soil particles. This structure augments water holding and soil stabilization capacities and constitutes an early stage in soil crust development. In addition, numerous cephalodia are formed within the hypothallus and subsequently develop upwards towards the thallus surface, sometimes before the formation of squamules with green algae. These anatomical and morphological strategies together with physiological properties such as the long photosynthetic activity period (measured in the laboratory) help explain its pioneering role as a colonizer and its apparently high growth rate.