Herbivory on Temperate Rainforest Seedlings in Sun and Shade: Resistance, Tolerance and Habitat Distribution

Differential herbivory and/or differential plant resistance or tolerance in sun and shade environments may influence plant distribution along the light gradient. Embothrium coccineum is one of the few light-demanding tree species in the temperate rainforest of southern South America, and seedlings are frequently attacked by insects and snails. Herbivory may contribute to the exclusion of E. coccineum from the shade if 1) herbivory pressure is greater in the shade, which in turn can result from shade plants being less resistant or from habitat preferences of herbivores, and/or 2) consequences of damage are more detrimental in the shade, i.e., shade plants are less tolerant. We tested this in a field study with naturally established seedlings in treefall gaps (sun) and forest understory (shade) in a temperate rainforest of southern Chile. Seedlings growing in the sun sustained nearly 40% more herbivore damage and displayed half of the specific leaf area than those growing in the shade. A palatability test showed that a generalist snail consumed ten times more leaf area when fed on shade leaves compared to sun leaves, i.e., plant resistance was greater in sun-grown seedlings. Herbivore abundance (total biomass) was two-fold greater in treefall gaps compared to the forest understory. Undamaged seedlings survived better and showed a slightly higher growth rate in the sun. Whereas simulated herbivory in the shade decreased seedling survival and growth by 34% and 19%, respectively, damaged and undamaged seedlings showed similar survival and growth in the sun. Leaf tissue lost to herbivores in the shade appears to be too expensive to replace under the limiting light conditions of forest understory. Following evaluations of herbivore abundance and plant resistance and tolerance in contrasting light environments, we have shown how herbivory on a light-demanding tree species may contribute to its exclusion from shade sites. Thus, in the shaded forest understory, where the seedlings of some tree species are close to their physiological tolerance limit, herbivory could play an important role in plant establishment

Highly concentrated bitumen emulsions. A state of the art, review of experimental results

Les emulsions concentrades o altament concentrades de betum són un camp molt poc estudiat avui en dia. El treball és un estat de l'art de tots els papers que hi ha sobre aquest tema desde el mètode tradicional fins el HIPR (High Internal Phase Ratio)

Parallel functional differentiation of an invasive annual plant on two continents.

Rapid local adaptation frequently occurs during the spread of invading species. It remains unclear, however, how consistent, and therefore potentially predictable, such patterns of local adaptation are. One approach to this question is to measure patterns of local differentiation in functional traits and plasticity levels in invasive species in multiple regions. Finding consistent patterns of local differentiation in replicate regions suggests that these patterns are adaptive. Further, this outcome indicates that the invading species likely responds predictably to selection along environmental gradients, even though standing genetic variation is likely to have been reduced during introduction. We studied local differentiation in the invasive annual plant Erodium cicutarium in two invaded regions, California and Chile. We collected seeds from across strong gradients in precipitation and temperature in Mediterranean-climate parts of the two regions (10 populations per region). We grew seeds from maternal families from these populations through two generations and exposed the second generation to contrasting levels of water and nutrient availability. We measured growth, flowering time and leaf functional traits across these treatments to obtain trait means and plasticity measures. We found strong differentiation among populations in all traits. Plants from drier environments flowered earlier, were less plastic in flowering time and reached greater size in all treatments. Correlations among traits within regions suggested a coordinated evolutionary response along environmental gradients associated with growing season length. There was little divergence in traits and trait intercorrelations between regions, but strongly parallel divergence in traits within regions. Similar, statistically consistent patterns of local trait differentiation across two regions suggest that local adaptation to environmental gradients has aided the spread of this invasive species, and that the formation of ecotypes in newly invaded environments has been relatively consistent and predictable

Forests are not immune to plant invasions: phenotypic plasticity and local adaptation allow Prunella vulgaris to colonize a temperate evergreen rainforest

El pdf del artículo es la versión post-print.In the South American temperate evergreen rainforest (Valdivian forest), invasive plants are mainly restricted to open sites, being rare in the shaded understory. This is consistent with the notion of closed-canopy forests as communities relatively resistant to plant invasions. However, alien plants able to develop shade tolerance could be a threat to this unique forest. Phenotypic plasticity and local adaptation are two mechanisms enhancing invasiveness. Phenotypic plasticity can promote local adaptation by facilitating the establishment and persistence of invasive species in novel environments. We investigated the role of these processes in the recent colonization of Valdivian forest understory by the perennial alien herb Prunella vulgaris from nearby populations in open sites. Using reciprocal transplants, we found local adaptation between populations. Field data showed that the shade environment selected for taller plants and greater specific leaf areas. We found population differentiation and within-population genetic variation in both mean values and reaction norms to light variation of several ecophysiological traits in common gardens from seeds collected in sun and shade populations. The colonization of the forest resulted in a reduction of plastic responses to light variation, which is consistent with the occurrence of genetic assimilation and suggests that P. vulgaris individuals adapted to the shade have reduced probabilities to return to open sites. All results taken together confirm the potential for rapid evolution of shade tolerance in P. vulgaris and suggest that this alien species may pose a threat to the native understory flora of Valdivian forest. © 2010 Springer Science+Business Media B.V.OG wants to acknowledge financial support provided by the Spanish Ministry for Education and Science grants RASINV GL2004-04884-C02 02/BOS (as part of the coordinate project RINVE). A CSIC CONICYT collaborative grant to FV and EG contributed to the development of this study.Peer Reviewe

How and when fungal endophytes can eliminate the plant growth–defence trade-off: mechanistic perspectives

A central paradigm in plant biology is that there is a trade-off between growth and defence against biotic stresses (Herms & Mattson, 1992; Lind et al., 2013; Karasov et al., 2017; Zust & € Agrawal, 2017; Monson et al., 2022). This paradigm is based on recurrent observations that increased production of chemical defences is associated with compromised plant growth, and it provides obvious limits to increasing the productivity of plants that must also resist pests and pathogens (Ballare & Austin, 2019; Ha et al., 2021; Sestari & Campos, 2021).We have recently challenged this paradigm by proposing that fungal endophytes can simultaneously increase plant growth and defence against biotic stresses (Fig. 1) (Bastıas et al., 2021).Fil: Bastías, Daniel A.. Grasslands Research Centre; Nueva ZelandaFil: Gundel, Pedro Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Universidad de Talca; ChileFil: Johnson, Richard D.. Grasslands Research Centre; Nueva ZelandaFil: Gianoli, Ernesto. Universidad de La Serena; Chil

Diversidad genética intra-poblacional de plantas trepadoras y árboles en un bosque templado en Chile central

The climbing habit is a key innovation in angiosperm evolution: climbing plant taxa have greater species richness than their non-climbing sister groups. It is considered that highly diversified clades should show increased among-population genetic differentiation. Less clear is the expected pattern regarding within-population genetic diversity in speciose lineages. We tested the hypothesis of greater within-population genetic diversity in climbing plants compared to trees in a temperate forest in central Chile. The assumption underlying this hypothesis is that higher among-population differentiation in climbers compared to trees should reflect higher genetic diversity as well. AFLP markers from 167 individual plants from 14 species (seven climbers and seven trees) were used to estimate the following indices of within-population genetic diversity: mean unbiased expected heterozygosity (HE), percentage of polymorphic loci (PPL), Shannon information index (I), and the effective number of alleles (NE). Overall, within-population genetic diversity did not differ between climbing plants and trees. The HE for climbing plants was slightly higher than that of trees (0.247 vs. 0.231), and PPL was higher in trees (93.6) than in climbers (81.8), but these differences were not statistically significant. Both I and NE were very similar for both groups. The expected greater genetic diversity in climbers might have been counterbalanced by tree-related ecological factors that turned to be relevant in the species assemblages studied. Results of this preliminary study should be further confirmed with a broader approach including several forest sites and larger sample sizes.El hábito trepador es una innovación clave en la evolución de las angiospermas: los taxa de plantas trepadoras poseen mayor riqueza de especies que sus grupos hermanos no-trepadores. Se considera que clados altamente diversificados debieran mostrar mayor diferenciación genética entre poblaciones. Menos claro es el patrón esperado respecto a la diversidad genética al interior de las poblaciones en linajes especiosos. Evaluamos la hipótesis de mayor diversidad genética intrapoblacional en plantas trepadoras en comparación con árboles en un bosque templado en Chile central. El supuesto detrás de esta hipótesis es que la mayor diferenciación poblacional en las trepadoras, comparadas con los árboles, debiera reflejar una mayor diversidad genética también. Marcadores AFLP de 167 plantas individuales de 14 especies (siete trepadoras y siete árboles) fueron usados para estimar los siguientes índices de diversidad genética intra-poblacional: heterocigosidad esperada media (HE), porcentaje de loci polimórficos (PPL), índice de información de Shannon (I), y el número efectivo de alelos (NE). En general, la diversidad genética intra-poblacional no difirió entre plantas trepadoras y árboles. La HE para plantas trepadoras fue levemente mayor a la de los árboles (0,247 vs. 0,231), y el PPL fue más alto en árboles (93,6) que en trepadoras (81,8), pero estas diferencias no fueron estadísticamente significativas. Tanto I como NE fueron muy similares en ambos grupos. La mayor diversidad genética esperada en trepadoras puede hacer sido contrarrestada por factores ecológicos particulares a los árboles que resultaron ser relevantes en los ensambles de especies estudiados. Los resultados de este estudio preliminar debieran ser confirmados con una aproximación a mayor escala, incluyendo varios sitios en el bosque y mayores tamaños muestrales

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

An Automatic Palindrome Generator

In 1984 Dan Hoey, a US naval mathematician, wrote a computer which he used to create a 540-word expansion of Leigh Mercer\u27s Panama palindrome (PD). It began A man, a plan, a caret, a ban, a myriad, a sum, a lac... and ended ...a calmus, a diaryman, a bater, a canal Panama. (For the full PD, plus additional information, see http://www2.vo.lu/homepages/phahn/anagrams/panama/htm.