¿Pueden los rasgos hidráulicos ayudar a explicar los límites de distribución actual en dos especies de Nothofagus en los Andes de Chile?

The Andes of central Chile is a geographical gradient with a marked variation in its climatic conditions. Along its slopes, are distributed the evergreen Nothofagus dombeyi and deciduous Nothofagus pumilio species that show differences in their leaf habits, range extensions, and in their limits of latitudinal distribution. Plant ecology proposes that unfavorable climatic conditions are limiting factors that determine the tree species distributions and that the functional hydraulic traits responses allow understanding the mechanisms underlying the current distribution of them. We hypothesize that both species will have lower mean values of K L and K S in populations near to distribution limits compared with middle populations due that unfavorable climatic conditions are predominant in the latitudinal range limits. We quantify in situ the leaf (K L ) and xylem (K S ) specific hydraulic conductivities in populations of N. dombeyi and N. pumilio near their northern and southern limits of distribution as well as in a middle population along Chilean Andes. Results showed that both species had lower mean values in populations near northern and southern limits compared to populations distributed in middle sites. Also, we found that the hydraulic performance population of N. pumilio distributed in the middle site had higher than N. dombeyi. We concluded that lower hydraulic conductivity associated with distribution limits for both study species implies a lower probability of being affected by embolism, independently of their leaf habits, showing a functional hydraulic convergence to low water availability orLos Andes de Chile es un gradiente geográfico latitudinal con una marcada variación de sus condiciones climáticas. A lo largo de sus laderas se distribuyen la siempreverde Nothofagus dombeyi y la decidua Nothofagus pumilio, las cuales difieren en sus hábitos foliares, extensión de sus rangos y límites de distribución latitudinal. La ecología vegetal propone que las condiciones climáticas desfavorables son factores limitantes en la distribución de las especies arbóreas, y que las respuestas de los rasgos funcionales hidráulicos permiten entender los mecanismos a los que subyace la distribución actual de estas. Hipotetizamos que ambas especies tendrán bajos valores promedio de la conductividad hidráulica específica de hoja (K L ) y del xilema (K S ) en poblaciones cercanas a sus límites de distribución comparado con poblaciones centrales, ya que las primeras tienen predominantemente condiciones climáticas desfavorables. Cuantificamos in situ la K L y K S , en poblaciones cercanas a los límites septentrionales y meridionales como una población central para N. dombeyi y N. pumilio a lo largo de los Andes de Chile. Los resultados muestran que ambas especies el K L y K S tuvieron valores promedios más bajos en sus sitios septentrionales y meridionales comparados con sus sitios centrales. Además, el desempeño hidráulico de los individuos de N. pumilio del sitio central fue mayor que N. dombeyi. Concluimos que una menor conductividad hidráulica asociada a los límites de distribución para ambas especies estudiadas, implica una menor probabilidad de verse afectadas por el embolismo, independiente de su hábito foliar, mostrando una convergencia funcional hidráulica frente a menor disponibilidad de agua o frío

Caracterización morfológica cuantitativa y cualitativa a nivel foliar de clones de Aristotelia chilensis (Mol.) Stuntz (maqui)

40 p.Aristotelia chilensis es un árbol perenne y dioico perteneciente a la familia Elaecarpaceae. Latitudinamente en Chile es posible encontrarlo desde la Región de Coquimbo hasta la Región de Aysen, e incluso en el Archipiélago Juan Fernández donde es considerado maleza. El fruto de maqui es conocido por sus propiedades antioxidantes y uno de los más saludables que puede proveer la naturaleza. Debido a su alto valor comercial, el maqui ha sido cosechado de manera natural depredando sus ramas y limitando la regeneración de las poblaciones naturales de esta especie. Esto ha motivado a la domesticación de la especie por parte de la Universidad de Talca y Fundación Chile a través de una mirada más sustentable y de preservación con un enfoque de un modelo de producción intensiva. En ese sentido, se caracterizaron 11 clones de maqui de 7 años de edad, a través de rasgos cuantitativos y cualitativos en base a su morfología foliar, establecidos en el Centro Experimental Panguilemo. Los clones se evaluaron y se ordenaron a través de su interés comercial, interés reproductivo (llamados polinizantes) y su interés en potenciales estudios futuros. Se encontraron diferencias significativas entre pares (test Mann-Whitney valor p≤0,05) de clones con respecto a su área foliar entre los clones Pudú-Huiña y Pudú 506, perímetro de la hoja entre Pudú-Huiña y Pudú-506, relación largo de la hoja/ancho de la hoja entre Huiña-Vicuña, Luna Nueva-506 y Huiña-506, distancia entre venas de segundo orden entre Luna Nueva-506, número de “lóbulos” entre 506-319 y 506-Vicuña, distancia de “lóbulos” en el borde de la hoja entre Pudú-Hiña y Pudú- Vicuña y distancia entre las sinuosidades de los lóbulos entre los clones entre Pudú-Huiña y Pudú-Vicuña. Estos rasgos sirven para buscar diferencias morfológicas a nivel foliar entre los genotipos y poder caracterizarlos. En relación a los rasgos cualitativos, la diferenciación más evidente se dio al medir la forma de la base o el tipo de margen, puesto que la forma del ápice y lámina se relaciona básicamente a los rasgos propios de la especie. // ABSTRACT: Aristotelia chilensis is a perennial and dioecious tree belonging to the Elaecarpaceae family. Latitudinally in Chile it can be found from the Coquimbo Region to the Aysen Region, and even in the Juan Fernandez Archipelago where it is considered a bush. The maqui fruit is known for its antioxidant properties and is one of the healthiest fruits that nature can provide. Due to its high commercial value, maqui has been harvested in a natural way, depredating its branches and limiting the regeneration of the natural populations of this species. This has motivated the domestication of the species by the University of Talca and Fundación Chile through a more sustainable and preserving approach with an intensive production model. Eleven 7-year-old maqui clones were characterized through quantitative and qualitative traits based on their leaf morphology, established at the Panguilemo Experimental Center. Clones were evaluated and ranked according to their commercial interest, reproductive interest (called pollinators) and interest in potential future studies. Significant differences were found between pairs (Mann-Whitney test value p≤0.05) of clones with respect to their leaf area between clones Pudú-Huiña and Pudú 506, leaf perimeter between Pudú-Huiña and Pudú-506, leaf length/leaf width ratio between Huiña-Vicuña, Luna Nueva-506 and Huiña-506, distance between second order veins between Luna Nueva-506, number of "lobes" between 506-319 and 506-Vicuña, distance of "lobes" at leaf edge between Pudú-Huiña and Pudú-Vicuña and distance among lobe sinuosities between clones of Pudú-Huiña and Pudú-Vicuña. These traits are used to look for morphological differences at the leaf level between genotypes and to characterize them. In relation to qualitative traits, the most evident differentiation occurred when measuring the shape of the base or the type of margin, since the shape of the apex and lamina is basically related to the traits of the specie

Plasticidad fenotípica en dos poblaciones antárticas de Colobanthus quitensis (Caryophyllaceae) bajo un escenario simulado de cambio global

Antarctica is characterized by extreme environmental conditions, which limit the establishment of vascular plants. Theseenvironmental conditions include low temperatures, short growing season and shortage of water and nutrients. Lowwater availability has been suggested as the main constraint to successful establishment, because it adversely affects thereproductive and physiological responses of plants. Colobanthus quitensis (Kunth) Bartl. (Caryophyllaceae) is one of thetwo native vascular plants that inhabit the Maritime Antarctic and its physiological performance and recruitment have beenshown to be negatively affected by soil water stress in the Antarctica. Phenotypic plasticity and local adaptation would be two of the main strategies of C. quitensis to cope with adverse environmental conditions prevailing in the Antarcticcontinent. It has been suggested that, under a future climate change scenario, water availability will increase by 30-40%,improving the conditions for plant establishment. In this study we evaluated in a common garden experiment, conductedin growth chambers, the morpho-physiological plasticity and reproductive effort in C. quitensis individuals from two siteslocated in the Shetland Islands, under a simulated scenario of climate change (40% increase in water availability) and underthe current situation (water availability recorded in the sites of origin). Overall, individuals of C. quitensis of both sitesshowed a plastic response, increasing the photochemical efficiency, leaf width and length and reproductive effort underincreased water availability. Plasticity was greater in those individuals from the more arid site as compared to con-specificsfrom a mesic site. If current climate change patterns are maintained, abiotic conditions could become more favorable for C.quitensis, improving ecophysiological performance and allowing the spread of its range in the Antarctic.  La Antártica se caracteriza por presentar condiciones ambientales extremas, lo cual limita el establecimiento de las plantasvasculares. Dentro de dichas características ambientales están las bajas temperaturas, corta estación de crecimiento yel estrés hídrico y nutricional. La baja disponibilidad hídrica ha sido sugerida como la principal limitante para el éxitode establecimiento, debido a que afecta de manera negativa las respuestas fisiológicas y reproductivas de las plantas.Colobanthus quitensis (Kunth) Bartl. (Caryophyllaceae) es una de las dos plantas vasculares nativas que habitan la AntárticaMarítima y se ha demostrado que su desempeño fisiológico y reclutamiento es afectado negativamente por el estrés hídricodel suelo. La plasticidad fenotípica y la adaptación local serían dos de las principales estrategias de C. quitensis para lidiarcon las adversas condiciones ambientales que predominan en el continente antártico. Se ha documentado que, bajo unescenario futuro de cambio climático, la disponibilidad hídrica en la Antártica aumentaría entre un 30-40%, mejorando lascondiciones para el establecimiento. En el presente trabajo evaluamos mediante un experimento de jardín común, realizadoen cámaras de crecimiento, la plasticidad morfo-fisiológica y el esfuerzo reproductivo en individuos de C. quitensisprovenientes de dos sitios en las Islas Shetland, bajo un escenario simulado de cambio climático (aumento en un 40% dela disponibilidad hídrica) y bajo la situación actual (disponibilidad hídrica registrada en los sitios de origen). En general,los individuos de C. quitensis de ambos sitios presentaron evidencia de plasticidad, aumentando su eficiencia fotoquímica,largo y ancho foliar, y esfuerzo reproductivo bajo la condición de aumento en la disponibilidad hídrica. La magnitud delaumento en la respuesta plástica fue mayor en aquellos individuos provenientes del sitio más árido en comparación a suscon-específicos del sitio más húmedo. Si los actuales patrones de cambio climático se mantienen, las condiciones abióticaspodrían volverse más favorables para C. quitensis, mejorando su desempeño ecofisiológico y permitiendo la expansión desu rango de distribución sobre la Antártica

Biological interactions and simulated climate change modulates the ecophysiological performance of Colobanthus quitensis in the Antarctic ecosystem

Most climate and environmental change models predict significant increases in temperature and precipitation by the end of the 21st Century, for which the current functional output of certain symbioses may also be altered. In this context we address the following questions: 1) How the expected changes in abiotic factors (temperature, and water) differentially affect the ecophysiological performance of the plant Colobanthus quitensis? and 2) Will this environmental change indirectly affect C. quitensis photochemical performance and biomass accumulation by modifying its association with fungal endophytes? Plants of C. quitensis from King George Island in the South Shetland archipelago (62°09′ S), and Lagotellerie Island in the Antarctic Peninsula (65°53′ S) were put under simulated abiotic conditions in growth chambers following predictive models of global climate change (GCC). The indirect effect of GCC on the interaction between C. quitensis and fungal endophytes was assessed in a field experiment carried out in the Antarctica, in which we eliminated endophytes under contemporary conditions and applied experimental watering to simulate increased precipitation input. We measured four proxies of plant performance. First, we found that warming (+W) significantly increased plant performance, however its effect tended to be less than watering (+W) and combined warming and watering (+T°+W). Second, the presence of fungal endophytes improved plant performance, and its effect was significantly decreased under experimental watering. Our results indicate that both biotic and abiotic factors affect ecophysiological performance, and the directions of these influences will change with climate change. Our findings provide valuable information that will help to predict future population spread and evolution through using ecological niche models under different climatic scenarios

Flora vascular de un remanente de bosque esclerófilo mediterráneo costero: Estación de Biología Terrestre de Hualpén, Región del Biobío, Chile

The remnants of coastal Mediterranean sclerophyll forests in Chile have a low representativeness in the National Systemof Protected Wild Areas despite their high endemism and species richness. In the Biobío Region, the Hualpén TerrestrialBiology Station (EBT) protects a remnant of this type of forest, for which there are no revisions describing its flora, whichmakes it difficult to formulate and develop strategies for its protection and conservation. This work aims are: a) to describethe taxonomic composition of vascular plants of the ETB and b) to provide information on their geographical origin, habitand conservation status. The resulting floristic list includes species identified through systematic sampling in the study areafor one year, as well as EBT species stored in the collection of the Universidad de Concepción Herbarium. We identified292 species of vascular plants, where 71 species are endemic, 124 are native, 99 are alien species. From the floristic pointof view the Asteraceae family was the most diverse with 36 species, followed by Poaceae with 32 species and Fabaceaewith 18 species. Herbs were the most frequent growth habit (77.2%), followed by shrub (13.9%), tree (7.5%) and sub-shrub(1.4%). Nineteen endemic and native species have been classified in some category of conservation in continental Chile,standing out Gomortega keule and Pitavia punctata both classified as endangered species, and the fern Asplenium trilobumclassified as a least concern in Chile and vulnerable in the Biobío Region. Despite of the reduced protected area in the EBT(70 ha), the site has a high species richness of native species when compared with data obtained from other studies of florain sites of central Chile.  Los remanentes de los bosques esclerófilos mediterráneos costeros en Chile tienen una baja representatividad en elSistema Nacional de Áreas Silvestres Protegidas, a pesar de su alto endemismo y riqueza de especies. En la Región delBiobío, la Estación de Biología Terrestre de Hualpén (EBT) conserva un remanente de este tipo de bosque, para el cual noexisten revisiones que describan su flora, lo que dificulta la formulación y el desarrollo de estrategias para su proteccióny conservación. Este trabajo tiene como objetivos: a) describir la composición taxonómica de las plantas vasculares de laETB y b) entregar información sobre su origen geográfico, hábito y estado de conservación. El listado florístico obtenidoincluye tanto las especies determinadas a través del muestreo sistemático en el área de estudio durante un año, así como lasespecies de la EBT ingresadas en la colección del Herbario de la Universidad de Concepción. Se determinaron 294 especiesde plantas vasculares de las cuales 71 son endémicas, 124 son nativas y 99 son introducidas. Desde el punto de vistaflorístico, la familia Asteraceae fue la má diversa con 36 especies, seguidas de Poaceae con 32 especies y Fabaceae con 18especies. Las hierbas fueron el hábito de crecimiento más frecuente (77,2%), seguida de las categorías arbusto (13,9%),árbol (7,5%) y subarbustos (1,4%). Diecinueve especies endémicas y nativas han sido clasificadas en alguna categoría deconservación en Chile continental, destacando Gomortega keule y Pitavia punctata, ambas clasificadas como especies Enpeligro, y el helecho Asplenium trilobum catalogado bajo la categoría Preocupación menor en Chile y Vulnerable en laRegión del Biobío. A pesar de la reducida superficie protegida en la EBT (70 ha), el lugar cuenta con una alta riqueza deespecies nativas si se la compara con datos obtenidos en otros estudios de flora en sitios de Chile central

Differential Impact of an Eclipse on Photosynthetic Performance of Trees with Different Degrees of Shade Tolerance

Solar eclipses represent a natural and unexpected event for plants that can potentially affect photosynthetic performance at the individual level. This effect, however, has seldom been evaluated. Here, we measured the impact of a total solar eclipse on the photosynthetic rate of different tree species—located in the Bosque Fray Jorge National Park, Chile—with varying degrees of shade tolerance. Specifically, we assessed whether the rapid and progressive light limitation facilitated by a solar eclipse would negatively impact the photosynthetic responses of these tree species and whether their photosynthetic performance would have a greater decrease when the percentage of eclipse shadow was higher, particularly in the less shade-tolerant species. To accomplish this, we compared daily changes in the photosynthetic rates of three tree species during a control (non-eclipse) vs. an eclipse day that occurred on 2 July 2019. Overall, tree species showed differences between a non-eclipse and eclipse day in the daily dynamics of their photosynthetic performance, with this trend being most evident at the peak of the solar eclipse. Additionally, each species showed a different pattern of de-epoxidation in accordance with its degree of shade tolerance. Our results suggest that solar eclipses negatively affect the photosynthesis of the studied Chilean tree species, which may be related to energy dissipation capacity via the de-epoxidation of xanthophyll pigments. This effect was more evident in shade-intolerant species, indicating that eclipses can present different consequences for the overall performance of various plant species

Assessing the importance of human activities for the establishment of the invasive Poa annua in Antarctica

Because of its harsh environmental conditions and remoteness, Antarctica is often considered to be at low risk of plant invasion. However, an increasing number of reports have shown the presence and spread of non-native plants in Antarctica; it is therefore important to study which factors control the invasion process in this ecosystem. Here, we assessed the role of different human activities on the presence and abundance of the invasive Poa annua. In addition, we performed a reciprocal transplant experiment in the field, and a manipulative experiment of germination with P. annua and the natives Colobanthus quitensis and Deschampsia antarctica, in order to unravel the effects of physical soil disturbance on the establishment and survival of P. annua. We found a positive correlation between abundance of P. annua and level of soil disturbance, and that survival of P. annua was 33% higher in sites with disturbed soil than non-disturbed. Finally, we found that disturbance conditions increased germination for P. annua, whereas for native species germination in experimentally disturbed soil was either unchanged or reduced compared to undisturbed soil. Our results indicate that human activities that modify abiotic soil characteristics could play an important role in the abundance of this invasive species. If the current patterns of human activities are maintained in Antarctica, the establishment success and spread of P. annua could increase, negatively affecting native flora

Occurrence of the on-native annual Bluegrass on the Antarctic mainland and its negative effects on native plants

Few non-native species have colonized Antarctica, although increased human activity and accelerated climate change may increase their number, distributional range, and effects on native species on the continent. We searched 13 sites on the maritime Antarctic islands and 12 sites on the Antarctic Peninsula for annual bluegrass (Poa annua), a non-native flowering plant. We also evaluated the possible effects of competition between P. annua and 2 vascular plants native to Antarctica, Antarctic pearlwort (Colobanthus quitensis) and Antarctic hairgrass (Deschampsia antarctica). We grew the native species in experimental plots with and without annual bluegrass under conditions that mimicked the Antarctic environment. After 5 months, we measured photosynthetic performance on the basis of chlorophyll fluorescence and determined total biomass of both native species. We found individual specimens of annual bluegrass at 3 different sites on the Antarctic Peninsula during the 2007–2008 and 2009–2010 austral summers. The presence of bluegrass was associated with a statistically significant reduction in biomass of pearlwort and hairgrass, whereas the decrease in biomass of bluegrass was not statistically significant. Similarly, the presence of bluegrass significantly reduced the photosynthetic performance of the 2 native species. Sites where bluegrass occurred were close to major maritime routes of scientific expeditions and of tourist cruises to Antarctica. We believe that if current levels of human activity and regional warming persist, more non-native plant species are likely to colonize the Antarctic and may affect native species

From dark to darkness, negative phototropism influences the support-tree location of the massive woody climber Hydrangea serratifolia (Hydrangeaceae) in a Chilean temperate rainforest

Climbing plants rely on suitable support to provide the light conditions they require in the canopy. Negative phototropism is a directional search behavior proposed to detect a support-tree, which indicates growth or movement away from light, based on light attenuation. In a Chilean temperate rainforest, we addressed whether the massive woody climber Hydrangea serratifolia (H. et A.) F. Phil (Hydrangeaceae) presents a support-tree location pattern influenced by light availability. We analyzed direction and light received in two groups of juvenile shoots: searching shoots (SS), with plagiotropic (creeping) growth vs. ascending shoots (AS), with orthotropic growth. We found that, in accordance with light attenuation, SS and AS used directional orientation to search and then ascend host trees. The light available to H. serratifolia searching shoots was less than that of the general forest understory; the directional orientation in both groups showed a significant deviation from a random distribution, with no circular statistical difference between them. Circular-linear regression indicated a relationship between directional orientations and light availability. Negative phototropism encodes the light environment’s heterogeneous spatial and temporal information, guiding the shoot apex to the most shaded part of the support-tree base, the climbing start point