Browsing by Author "Hepp, Josefina"

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    Characterisation of seed dormancy of 12 Chilean species of Nolana (Solanaceae) from the coastal Atacama Desert
    (CAMBRIDGE UNIV PRESS, 2021) Hepp, Josefina; Gomez, Miguel; Leon Lobos, Pedro; Montenegro, Gloria; Vilalobos, Luis; Contreras, Samuel
    The genus Nolana (Solanaceae) comprises numerous species endemic to the coastal Atacama Desert of Chile and Peru of high ornamental potential and conservation value. The environments in which these species have evolved and are present today correspond to particular conditions in the midst of a hyper-arid habitat, so the study of their germination requirements and characterisation of seed dormancy becomes important in terms of conservation but also for ecological and evolutionary purposes. Different treatments were performed on mericarps of 12 species of Nolana: control (intact seeds imbibed in distilled water), scarification in funicular plug and distilled water and scarification in funicular plug and addition of GA(3) (500 ppm); their permeability to water was also tested. It was determined that the species did not present physical dormancy, as had been previously reported, but rather physiological dormancy (PD). Germination results after treatments were not homogeneous among all 12 species, indicating differences in their dormancy levels. Also, the important role of the endosperm in the prevention of germination for the studied Nolana species was highlighted. Regarding the relationship between the level of PD (expressed as the percentage of germination for the most successful treatment) and the latitudinal distribution of the species or their phylogenetic closeness, it was determined that, for the studied species, their proximity in terms of clades was more relevant than their latitudinal distribution.
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    Characterization of seed dormancy of Nolana (Solanaceae) in the coastal Atacama Desert of Chile.
    (2019) Hepp, Josefina; Contreras E., Samuel; Pontificia Universidad Católica de Chile. Facultad de Agronomía e Ingeniería Forestal
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    Effects on the flora and vegetation of the extreme precipitation event of August 2015 in Alto Patache, Atacama Desert, Chile
    (PONTIFICA UNIV CATOLICA CHILE, INST GEOGRAFIA, 2017) Pliscoff, Patricio; Zanetta, Nicolas; Hepp, Josefina; Machuca, Javiera
    During the extreme precipitation event related with "El Nino", which occurred in August 2015 on the coast of the Tarapaca region, Atacama Desert, rainfall of 50 mm was recorded at the Alto Patache Fog Oasis (annual average of 1 mm), activating germination of many species present on the site. After the event, transects were demarcated and the presence and dominance of vegetation was recorded. The floristic data identified was compared with historical records and related with the distribution of fog, measured between the years 2001 and 2002. Results show 42 species identified, 78% of all known plants in the area, with one new record (Tiquilia sp.). The floristic analysis allowed the identification of three vegetation units, and a greater diversity of species was observed in lower areas of the coastal mountain chain.
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    Importance of water quality on plant abundance and diversity in high-alpine meadows of the Yerba Loca Natural Sanctuary at the Andes of north-central Chile
    (2008) Ginocchio, Rosanna; Hepp, Josefina; Bustamante, Elena; Silva, Yasna; Maria De La Fuente, Luz; Francois Casale, Jean; Paul De La Harpe, Jean; Urrestarazu, Paola; Anic, Vinka; Montenegro, Gloria
    Porphyry Cu-Mo deposits have influenced Surface water quality in high-Andes of north-central Chile since the Miocene. Water anomalies may reduce species abundance and diversity in alpine meadows as acidic and metal-rich waters are highly toxic to plants The study assessed the importance of surface water quality on plant abundance and diversity in high-alpine meadows at the Yerba Loca Natural Santuary (YLNS), central Chile (33 degrees 15' S, 70 degrees 18' W). Hydrochemical and plant prospecting were carried out on Piedra Carvajal, Chorrillos del Plomo and Lit Lata meadows the growing seasons of 2006 and 2007. Direct gradient analysis was performed through canonical correspondence analysis (CCA) to look for relationships among water chemistry and plant factors. High variability in water chemistry was found inside and among meadows, particularly for pH, sulphate, electric conductivity, hardness, and total dissolved Cu, Zn, Cd, Ph and Fe. Data oil species abundance and water chemical factors suggests that pH and total dissolved Cu are very important factor determining changes in plant abundance and diversity in study meadows. For instance, Festuca purpurascens, Colobanthus quitensis, and Arenaria rivularis are abundant in habitats with Cu-rich waters while Festuca magellanica, Patosita clandestina, Plantago barbata, Werneria pygmea, and Erigeron andicola are abundant in habitats with dilute waters.
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    Micropropagation of Nolana intonsa as a tool for its domestication and conservation
    (2024) Morales-Tapia, Pablo; Hepp, Josefina; Nassar, Daniel Alvaro Villegas; Takasaki, Alexis Kooichi Vidal
    A complete protocol of Nolana intonsa I. M. Johnst, micropropagation was developed. The culture media used were WPM, DKW, and MS as control. DKW medium produced the best results over in vitro development of N. intonsa , generating a significant increase in the multiplication rate, lateral shoots formation, height, and general quality of the plantlets. In the case of fresh weight, dry weight, and water content, no differences were observed between MS and DKW, but a significant decrease in these parameters was produced when the WPM medium was used. Subsequently, when DKW was defined as basal medium, the effect of auxin supplementation was also evaluated. The addition of IBA generated a desirable effect over the in vitro plantlets. The addition of 0.05 mg L -1 of IBA improve the multiplication rate, the shoot's development, plant's height, and reduced in a significant way the damage to the plantlets. Fresh weight, dry weight, and water contents also showed a significant increase when IBA supplementation was added to the DKW medium. The plants where acclimatization of the plantlets was possible, obtaining finished pot plants capable of growth under greenhouse conditions. The development of a micropropagation protocol of N. intonsa could help the conservation and sustainable utilization of this endemic Chilean species.
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    Seed dormancy of Nolana jaffuelii I.M.Johnst. (Solanaceae) in the coastal Atacama Desert
    (2015) Cabrera, Elisa; Hepp, Josefina; Gómez, Miguel; Contreras E., Samuel
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    Seeing through the clouds - Mapping desert fog oasis ecosystems using 20 years of MODIS imagery over Peru and Chile
    (2021) Moat, Justin; Orellana-Garcia, Alfonso; Tovar, Carolina; Arakaki, Monica; Arana, Cesar; Cano, Asuncion; Faundez, Luis; Gardner, Martin; Hechenleitner, Paulina; Hepp, Josefina; Lewis, Gwilym; Mamani, Jose-Manuel; Miyasiro, Maria; Whaley, Oliver Q.
    The desert fog oasis ecosystem of Peru and Chile comprises numerous oases along 3000 km of the Pacific coastal belt, it hosts a highly endemic flora, providing vital ecosystem services and genetic resources. However, due to their marked seasonality and fog cover they are poorly mapped, greatly compromising their conservation. Here we redress this using 479 images from the MODIS (MOD13Q1 V6 product) data/algorithm for the period 2000-2020, permitting the mapping of ephemeral vegetation, herbaceous and woody fog oases vegetation. In addition, we examine the main drivers of productivity in this unique ecosystem using generalised linear models, assess human pressures, conservation efforts, and summarise present plant diversity knowledge.