Tourist Trampling on a Peripheral Plant Population Restricted to an Urban Natural Area in the Capo Sant'Elia Promontory (Sardinia, W-Mediterranean Basin).

Urban natural areas provide important ecological services such as biodiversity conservation, as well as opportunities for people to connect with nature and preserve cultural heritage. However, the increasing demand for access to natural areas and the expansion of human recreational activities, such as hiking and biking, pose threats to these ecosystems, especially for animal and plant species, finally resulting in biodiversity loss. This study explores the intricate link between human trampling, plant density, and the morphological and reproductive characteristics of Globularia alypum L., a plant with a peripheral population in Sardinia restricted to a natural area within an urban context. The study examined trampling effects on 75 plots along a frequently used path crossing the plant's core population. Similar environmental conditions were assumed, with differences attributed to human trampling intensity and plant density, and morphological and reproductive traits were measured within each plot. Our results showed that human trampling caused differences in the morphological traits of plants, whereas, in contrast, reproductive traits are less vulnerable to human trampling than morphological ones. As a result, trampled areas may experience decreased plant recruitment, which can have long-term implications for plant population dynamics. Understanding the relationship between trampling effects and the sensitivity of peripheral plant populations is crucial for effective conservation and management strategies.

Climate warming impacts chewing Spodoptera litura negatively but sucking Corythucha marmorata positively on native Solidago canadensis.

Insect-plant interactions are among importantly ecological processes, and rapid environmental changes such as temperature and resource fluctuations can disrupt long-standing insect-plant interactions. While individual impacts of climate warming, atmospheric nitrogen (N) deposition, and plant provenance on insect-plant interactions are well studied, their joint effects on insect-plant interactions are less explored in ecologically realistic settings. To this end, we performed five experiments with native and invasive Solidago canadensis populations from home and introduced ranges and two insect herbivores (leaf-chewing Spodoptera litura and sap-sucking Corythucha marmorata) in the context of climate warming and N deposition. We determined leaf defensive traits, feeding preference, and insect growth and development, and quantified the possible associations among climate change, host-plant traits, and insect performance with structural equation modeling. First, native S. canadensis populations experienced higher damage by S. litura but lower damage by C. marmorata than invasive S. canadensis populations in the ambient environment. Second, warming decreased the leaf consumption, growth, and survival of S. litura on native S. canadensis populations, but did not affect these traits on invasive S. canadensis populations; warming increased the number of C. marmorata on native S. canadensis populations via direct facilitation, but decreased that on invasive S. canadensis populations via indirect suppression. Third, N addition enhanced the survival of S. litura on native S. canadensis populations, and its feeding preference and leaf consumption on invasive S. canadensis populations. Finally, warming plus N addition exhibited non-additive effects on insect-plant interactions. Based on these results, we tentatively conclude that climate warming could have contrasting effects on insect-plant interactions depending on host-plant provenance and that the effects of atmospheric N deposition on insects might be relatively weak compared to climate warming. Future studies should focus on the molecular mechanisms underlying these different patterns.

Effects of different ecological restoration methods on the soil physicochemical properties and vegetation community characteristics of the Baotou light rare earth tailings pond in Inner Mongolia, China.

This study investigated the soil physicochemical properties and vegetation community characteristics of the Baotou light rare earth tailings pond after 10 years of aggregate spray seeding ecological restoration (S1) and ordinary soil spray seeding ecological restoration (S2), and the naturally restored dam slope area without human intervention (S3). The results showed that the vegetation community of S1 was dominated by Caragana korshinskii Kom, and its importance and abundance values were 0.40 and 38.4, respectively, while the vegetation communities of S2 and S3 mainly comprised herbaceous plants. Additionally, the vegetation biomass of S1 was significantly higher than that of S2 and S3 by 215.20% and 1345.76%, respectively, and the vegetation diversity index of S1 was the highest among the three treatment groups. The soil porosity (SP), water content (W), electrical conductivity (EC), and available K were significantly improved in S1, while soil bulk density (BD) was significantly reduced compared with that of S2 and S3. In addition, redundancy analysis revealed that SP, EC, W, and K positively correlate with the biomass, Shannon, Pielou, Simpson, and Marglef indices. Principal component analysis further showed that the comprehensive score of S1 (0.983) was higher than that of S2 (- 0.261) and S3 (- 0.648). Collectively, these findings indicate that appropriate ecological restoration can improve soil structure and vegetation community characteristics, thereby accelerating vegetation restoration, ultimately increasing the stability of the ecosystem.

Plant interaction networks reveal the limits of our understanding of diversity maintenance.

Species interactions are key drivers of biodiversity and ecosystem stability. Current theoretical frameworks for understanding the role of interactions make many assumptions which unfortunately, do not always hold in natural, diverse communities. This mismatch extends to annual plants, a common model system for studying coexistence, where interactions are typically averaged across environmental conditions and transitive competitive hierarchies are assumed to dominate. We quantify interaction networks for a community of annual wildflowers in Western Australia across a natural shade gradient at local scales. Whilst competition dominated, intraspecific and interspecific facilitation were widespread in all shade categories. Interaction strengths and directions varied substantially despite close spatial proximity and similar levels of local species richness, with most species interacting in different ways under different environmental conditions. Contrary to expectations, all networks were predominantly intransitive. These findings encourage us to rethink how we conceive of and categorize the mechanisms driving biodiversity in plant systems.

High-resolution data are necessary to understand the effects of climate on plant population dynamics of a forest herb.

Climate is assumed to strongly influence species distribution and abundance. Although the performance of many organisms is influenced by the climate in their immediate proximity, the climate data used to model their distributions often have a coarse spatial resolution. This is problematic because the local climate experienced by individuals might deviate substantially from the regional average. This problem is likely to be particularly important for sessile organisms like plants and in environments where small-scale variation in climate is large. To quantify the effect of local temperature on vital rates and population growth rates, we used temperature values measured at the local scale (in situ logger measures) and integral projection models with demographic data from 37 populations of the forest herb Lathyrus vernus across a wide latitudinal gradient in Sweden. To assess how the spatial resolution of temperature data influences assessments of climate effects, we compared effects from models using local data with models using regionally aggregated temperature data at several spatial resolutions (≥1 km). Using local temperature data, we found that spring frost reduced the asymptotic population growth rate in the first of two annual transitions and influenced survival in both transitions. Only one of the four regional estimates showed a similar negative effect of spring frost on population growth rate. Our results for a perennial forest herb show that analyses using regionally aggregated data often fail to identify the effects of climate on population dynamics. This emphasizes the importance of using organism-relevant estimates of climate when examining effects on individual performance and population dynamics, as well as when modeling species distributions. For sessile organisms that experience the environment over small spatial scales, this will require climate data at high spatial resolutions.

Pollinator-mediated effects of landscape-scale land use on grassland plant community composition and ecosystem functioning - seven hypotheses.

Environmental change is disrupting mutualisms between organisms worldwide. Reported declines in insect populations and changes in pollinator community compositions in response to land use and other environmental drivers have put the spotlight on the need to conserve pollinators. While this is often motivated by their role in supporting crop yields, the role of pollinators for reproduction and resulting taxonomic and functional assembly in wild plant communities has received less attention. Recent findings suggest that observed and experimental gradients in pollinator availability can affect plant community composition, but we know little about when such shifts are to be expected, or the impact they have on ecosystem functioning. Correlations between plant traits related to pollination and plant traits related to other important ecosystem functions, such as productivity, nitrogen uptake or palatability to herbivores, lead us to expect non-random shifts in ecosystem functioning in response to changes in pollinator communities. At the same time, ecological and evolutionary processes may counteract these effects of pollinator declines, limiting changes in plant community composition, and in ecosystem functioning. Despite calls to investigate community- and ecosystem-level impacts of reduced pollination, the study of pollinator effects on plants has largely been confined to impacts on plant individuals or single-species populations. With this review we aim to break new ground by bringing together aspects of landscape ecology, ecological and evolutionary plant-insect interactions, and biodiversity-ecosystem functioning research, to generate new ideas and hypotheses about the ecosystem-level consequences of pollinator declines in response to land-use change, using grasslands as a focal system. Based on an integrated set of seven hypotheses, we call for more research investigating the putative pollinator-mediated links between landscape-scale land use and ecosystem functioning. In particular, future research should use combinations of experimental and observational approaches to assess the effects of changes in pollinator communities over multiple years and across species on plant communities and on trait distributions both within and among species.

Adult conspecific density affects Janzen-Connell patterns by modulating the recruitment exclusion zones.

Plant-soil negative feedback (NF) is a well-established phenomenon that, by preventing the dominance of a single species, allows species coexistence and promotes the maintenance of biodiversity. At community scale, localized NF may cause the formation of exclusion zones under adult conspecifics leading to Janzen-Connell (JC) distribution. In this study, we explore the connection between adult density, either conspecifics or heterospecifics, on the probability of occurrence of JC distributions. Using an individual-based modelling approach, we simulated the formation of exclusion zones due to the build-up of NF in proximity of conspecific adult plants and assessed the frequency of JC distribution in relation to conspecifics and heterospecifics density ranging from isolated trees to closed forest stands. We found that JC recruitment distribution is very common in the case of an isolated tree when NF was strong and capable to form an exclusion zone under the parent tree. At very low NF intensity, a prevalence of the decreasing pattern was observed because, under such conditions, the inhibitory effect due to the presence of the mother tree was unable to overcome the clustering effect of the seed dispersal kernel. However, if NF is strong the JC frequency suddenly decreases in stands with a continuous conspecific cover likely as a result of progressive expansion of the exclusion zone surrounding all trees in closed forest stands. Finally, our simulations showed that JC distribution should not be frequent in the case of rare species immersed in a matrix of heterospecific adults. Overall, the model shows that a plant suffering from strong NF in monospecific stands can rarely exhibit a recruitment pattern fitting the JC model. Such counterintuitive results would provide the means to reconcile the well-established NF framework with part the forest ecologists' community that is still skeptical towards the JC model. Synthesis: Our model highlights the complex interconnection between NF intensity, stand density, and recruitment patterns explaining where and why the JC distribution occurs. Moreover, predicting the occurrence of JC in relation to stand density we clarify the relevance of this ecological phenomenon for future integration in plant community frameworks.

Inference of future bog succession trajectory from spatial chronosequence of changing aapa mires.

Climate change-driven vegetation changes can alter the ecosystem functions of northern peatlands. Several case studies have documented fen-to-bog transition (FBT) over recent decades, which can have major implications, as increased bog growth would likely cause cooling feedback. However, studies beyond individual cases are missing to infer if a common trajectory or many alternatives of FBT are in progress. We explored plant community and hydrology patterns during FBT of 23 boreal aapa mire complexes in Finland. We focused on mires where comparisons of historical (1940-1970) and new (2017-2019) aerial photographs indicated an expansion of Sphagnum-dominated zones. Vegetation plot and water chemistry data were collected from string-flark fens, transition zones with indications of Sphagnum increase, and bog zones; thus, in a chronosequence with a decadal time span. We ask, is there a common trajectory or many alternatives of FBT in progress, and what are the main characteristics (species and traits) of transitional plant communities? We found a pattern of fen-bog transitions via an increase in Sphagnum sect. Cuspidata (mainly S. majus and S. balticum), indicating a consistently high water table. Indicators only of transitional communities were scarce (Sphagnum lindbergii), but FBT had apparently facilitated shallow-rooted aerenchymatous vascular plants, especially Scheuchzeria palustris. Water pH consistently reflected the chronosequence with averages of 4.2, 3.9, and 3.8, from fen to transition and bog zones. Due to weak minerotrophy of string-flark fens, species richness increased towards bogs, but succession led to reduced beta diversity and homogenization among bog sites. Decadal chronosequence suggested a future fen-bog transition through a wet phase, instead of a drying trend. Transitional poor-fen vegetation was characterized by the abundance of Sphagnum lindbergii, S. majus, and Scheuchzeria palustris. Sphagnum mosses likely benefit from longer growing seasons and consistently wet and acidic conditions of aapa mires.

Opposing effects of plant traits on diversification.

Species diversity can vary dramatically across lineages due to differences in speciation and extinction rates. Here, we explore the effects of several plant traits on diversification, finding that most traits have opposing effects on diversification. For example, outcrossing may increase the efficacy of selection and adaptation but also decrease mate availability, two processes with contrasting effects on lineage persistence. Such opposing trait effects can manifest as differences in diversification rates that depend on ecological context, spatiotemporal scale, and associations with other traits. The complexity of pathways linking traits to diversification suggests that the mechanistic underpinnings behind their correlations may be difficult to interpret with any certainty, and context dependence means that the effects of specific traits on diversification are likely to differ across multiple lineages and timescales. This calls for taxonomically and context-controlled approaches to studies that correlate traits and diversification.

Long-term exclusion of invasive ungulates alters tree recruitment and functional traits but not total forest carbon.

Forests are major carbon (C) sinks, but their ability to sequester C and thus mitigate climate change, varies with the environment, disturbance regime, and biotic interactions. Herbivory by invasive, nonnative ungulates can have profound ecosystem effects, yet its consequences for forest C stocks remain poorly understood. We determined the impact of invasive ungulates on C pools, both above- and belowground (to 30 cm), and on forest structure and diversity using 26 paired long-term (>20 years) ungulate exclosures and adjacent unfenced control plots located in native temperate rainforests across New Zealand, spanning 36-41° S. Total ecosystem C was similar between ungulate exclosure (299.93 ± 25.94 Mg C ha-1 ) and unfenced control (324.60 ± 38.39 Mg C ha-1 ) plots. Most (60%) variation in total ecosystem C was explained by the biomass of the largest tree (mean diameter at breast height [dbh]: 88 cm) within each plot. Ungulate exclusion increased the abundance and diversity of saplings and small trees (dbh ≥2.5, <10 cm) compared with unfenced controls, but these accounted for ~5% of total ecosystem C, demonstrating that a few, large trees dominate the total forest ecosystem C but are unaffected by invasive ungulates at a timescale of 20-50 years. However, changes in understory C pools, species composition, and functional diversity did occur following long-term ungulate exclusion. Our findings suggest that, although the removal of invasive herbivores may not affect total forest C at the decadal scale, major shifts in the diversity and composition of regenerating species will have longer term consequences for ecosystem processes and forest C.

Conservation of rare and endangered plant species in China.

Rare and endangered plant species (REPs) are facing high danger of extinction, yet a comprehensive and up-to-date review on their conservation in China is still lacking. This paper systematically collected studies and achievements on REPs conservation, including species surveys and monitoring, cause of endangerment, in situ conservation, ex situ conservation, reintroduction, propagation, conservation legislation, public participation, progress in conservation of wild plant with extremely small populations, and progress in China's implementation of the Convention on Biological Diversity. Although enormous advances have been made in conservation policies and legislations, protection systems, and research, as well as public education and international collaborations, the conservation efficiency is still restricted largely by the conflict between economic growth and biodiversity conservation in China. In order to meet its commitments to the new Post-2020 Global Biodiversity Framework, more work on basic investigation and long-term observation, as well as advanced technologies and application-oriented research on REPs should be carried out.

Produtividade de híbridos de milho pipoca submetidos a diferentes populações na semeadura / Productivity of poppy corn hybrids submitted to different populations in seeding / Productividad de híbridos de maíz poppy presentados a poblaciones diferentes en la sembrada

Quando se trata de milho pipoca o Brasil é o segundo maior produtor, mas necessitando ainda de importações para suprir a demanda interna do país, visto a importância de estudos que melhor explorem as recomendações agronômicas para a cultura do milho pipoca. Assim, o presente estudo objetivou avaliar o impacto da população de plantas sobre algumas variáveis morfológicas e na produtividade final de grãos de dois híbridos de milho pipoca (8203 e 4512). Foram estudadas as populações de 60.000, 65.000, 70.000, 75.000 e 80.000 plantas por ha-1 no espaçamento de 0,45cm entre linha de semeadura. O experimento foi conduzido no ano agrícola 2018/2019, na área experimental do Departamento de Ciências Agronômicas e Ambientais da Universidade Federal de Santa Maria, campus Frederico Westphalen ­ RS, em um delineamento de blocos casualizados em um esquema fatorial (2x5). O diâmetro de colmo, comprimento da espiga e peso de mil sementes diminuíram à medida que se aumentou a população de plantas. Para ambos os híbridos, e para a maioria das variáveis analisadas as densidades populacionais não interferiram de forma significativa na produtividade final de grãos do milho pipoca. Entretanto quando se trabalha a média das populações se observa uma superioridade do híbrido 8203 para as variáveis, altura de planta, altura de inserção da espiga, prolificidade, empalhamento, diâmetro de espiga, número de grãos por espiga, peso de mil sementes e produtividade final de grãos.(AU)

When it comes to popcorn, Brazil is the second largest producer, but still needing imports to supply the country's domestic demand, given the importance of studies that better explore agronomic recommendations for popcorn culture. Thus, the aim of the present study was to evaluate the impact of the plant population on some morphological variables and the final consumption of two hybrid popcorn kernels (8203 and 4512). The populations of 60.000, 65.000, 70.000, 75.000 and 80.000 plants per ha-1 were studied in the 0.45cm spacing between sowing lines. The experiment was carried out in the agricultural year 2018/2019, in the experimental area of the Department of Agricultural and Environmental Sciences of the Federal University of Santa Maria, Frederico Westphalen campus - RS, in a randomized block design in a factorial scheme (2x5). The stem diameter, ear length and weight of a thousand seeds decreased as the plant population increased. For both hybrids, and for most of the variables analyzed, population densities did not significantly affect the final grain yield of popcorn. However, when working with the average population, a superiority of the 8203 hybrid is observed for the variables, plant height, height of ear insertion, prolificacy, stuffing, ear diameter, number of grains per ear, weight of a thousand seeds and final productivity of grain.(AU)

En lo que respecta a las palomitas de maíz, Brasil es el segundo mayor productor, pero aún necesita importaciones para satisfacer la demanda interna del país, dada la importancia de los estudios que exploran mejor las recomendaciones agronómicas para el cultivo de palomitas de maíz. Por lo tanto, el objetivo del presente estudio fue evaluar el impacto de la población de plantas en algunas variables morfológicas y en el rendimiento final de grano de dos híbridos de palomitas de maíz (8203 y 4512). Se estudiaron las poblaciones de 60.000, 65.000, 70.000, 75.000 y 80.000 plantas por ha-1 en el espacio de 0.45cm entre líneas de siembra. El experimento se realizó en el año agrícola 2018/2019, en el área experimental del Departamento de Ciencias Agronómicas y Ambientales de la Universidad Federal de Santa María, campus Frederico Westphalen - RS, en un diseño de bloques al azar en un esquema factorial (2x5). El diámetro del tallo, la longitud de la mazorca y el peso de mil semillas disminuyeron à medida que aumentó la población de plantas. Para ambos híbridos, y para la mayoría de las variables analizadas, las densidades de población no afectaron significativamente el rendimiento final de grano de las palomitas de maíz. Sin embargo, cuando se trabaja con la población promedio, se observa una superioridad del híbrido 8203 para las variables, altura de la planta, altura de inserción de la mazorca, prolificidad, relleno, diámetro de la mazorca, número de granos por mazorca, peso de mil semillas y productividad final de grano.(AU)

Soil fungal communities show more specificity than bacteria for plant species composition in a temperate forest in China.

BACKGROUND: Soil microbiome is an important part of the forest ecosystem and participates in forest ecological restoration and reconstruction. Niche differentiation with respect to resources is a prominent hypothesis to account for the maintenance of species diversity in forest ecosystems. Resource-based niche differentiation has driven ecological specialization. Plants influence soil microbial diversity and distribution by affecting the soil environment. However, with the change in plant population type, whether the distribution of soil microbes is random or follows an ecologically specialized manner remains to be further studied. We characterized the soil microbiome (bacteria and fungi) in different plant populations to assess the effects of phytophysiognomy on the distribution patterns of soil microbial communities in a temperate forest in China. RESULTS: Our results showed that the distribution of most soil microbes in different types of plant populations is not random but specialized in these temperate forests. The distribution patterns of bacteria and fungi were related to the composition of plant communities. Fungal species (32%) showed higher specialization than bacterial species (15%) for different types of plant populations. Light was the main driving factor of the fungal community, and soil physicochemical factors were the main driving factor of the bacterial community. CONCLUSION: These findings suggest that ecological specialization is important in maintaining local diversity in soil microbial communities in this forest. Fungi are more specialized than bacteria in the face of changes in plant population types. Changes in plant community composition could have important effects on soil microbial communities by potentially influencing the stability and stress resistance of forest ecosystems.

CsMYB1 integrates the regulation of trichome development and catechins biosynthesis in tea plant domestication.

Tea trichomes synthesize numerous specialized metabolites to protect plants from environmental stresses and contribute to tea flavours, but little is known about the regulation of trichome development. Here, we showed that CsMYB1 is involved in the regulation of trichome formation and galloylated cis-catechins biosynthesis in tea plants. The variations in CsMYB1 expression levels are closely correlated with trichome indexes and galloylated cis-catechins contents in tea plant populations. Genome resequencing showed that CsMYB1 may be selected in modern tea cultivars, since a 192-bp insertion in CsMYB1 promoter was found exclusively in modern tea cultivars but not in the glabrous wild tea Camellia taliensis. Several enhancers in the 192-bp insertion increased CsMYB1 transcription in modern tea cultivars that coincided with their higher galloylated cis-catechins contents and trichome indexes. Biochemical analyses and transgenic data showed that CsMYB1 interacted with CsGL3 and CsWD40 and formed a MYB-bHLH-WD40 (MBW) transcriptional complex to activate the trichome regulator genes CsGL2 and CsCPC, and the galloylated cis-catechins biosynthesis genes anthocyanidin reductase and serine carboxypeptidase-like 1A. CsMYB1 integratively regulated trichome formation and galloylated cis-catechins biosynthesis. Results suggest that CsMYB1, trichome and galloylated cis-catechins are coincidently selected during tea domestication by harsh environments for improved adaption and by breeders for better tea flavours.

Managing White Mold on Common Bean with Type III Growth Habit by Integrating Partial Resistance, Plant Density, and Fungicide.

The combination of plant density, fungicide, and levels of genotype resistance to white mold (WM) has not been studied for its effect on performance of common bean with type III growth habit under WM pressure. We established four sprinkler-irrigated trials in the fall to winter season in Brazil, combining density (8, 14, 20, or 26 plants/m2), genotype (susceptible or partially resistant to WM), and fungicide to manage WM (two fluazinam applications or without fluazinam) at 0.5 m row spacing in fields infested with sclerotia. One trial was established in a warm region, aiming to obtain low WM pressure. For three trials, the linear mixed model was used. WM pressure in the trials ranged from low to high. Genotype × density × fungicide and genotype × density interactions were not significant for incidence, severity, and yield for all trials. In the three trials, severity was 29% lower at eight than at 26 plants/m2, and yield at 14 plants/m2 (3,294 kg/ha) was 14% higher than yield at eight plants/m2 (P = 0.035) where fluazinam was applied. However, without fluazinam, density did not affect yield. In conclusion, choices of plant density for type III bean cultivars do not need to take into account their resistance levels to WM in the fall to winter season. However, fungicide treatment to manage WM affects the choice of density, with 8 to 12 plants/m2 recommended if fungicide is not an option to manage WM (as in organic systems), and 10 to 14 plants/m2 recommended if fungicide applications are likely.

Niche Differentiation at Multiple Spatial Scales on Large and Small Mediterranean Islands for the Endemic Silene velutina Pourr. ex Loisel. (Caryophyllaceae).

The aim of this work is to investigate niche variations in endemic Silene velutina (Caryophyllaceae, Angiosperms) on Mediterranean islands that differ in size. Six populations on both large and small islands were sampled across the geographic range of the species. For each population, 10 plots (1 × 2 m, with a 25 cm grill) were randomly placed to quantify environmental (abiotic and biotic factors and disturbance) and population (demographic structure and reproductive success) parameters. Niche parameters related to substrate, plant cover, community diversity and composition and disturbance showed significant variation in relation to island size. At the regional scale, we detected a broader niche on large islands associated with spatial heterogeneity and island size. In contrast, at the local scale, populations on small islands showed a broader niche, potentially due to a release from competition (low diversity and plant cover and absence of phanerophytes). Populations on large islands had a demographic structure biased towards vegetative individuals (seedlings and juveniles) with few reproductive individuals, while those on small islands had a majority of adults. Together, the results on niche breadth and demographic structure concord with the idea of a strategy based on adult persistence on small islands.

Tree recruitment is determined by stand structure and shade tolerance with uncertain role of climate and water relations.

Tree regeneration is a key process for long-term forest dynamics, determining changes in species composition and shaping successional trajectories. While tree regeneration is a highly stochastic process, tree regeneration studies often cover narrow environmental gradients only, focusing on specific forest types or species in distinct regions. Thus, the larger-scale effects of temperature, water availability, and stand structure on tree regeneration are poorly understood.We investigated these effects in respect of tree recruitment (in-growth) along wide environmental gradients using forest inventory data from Flanders (Belgium), northwestern Germany, and Switzerland covering more than 40 tree species. We employed generalized linear mixed models to capture the abundance of tree recruitment in response to basal area, stem density, shade casting ability of a forest stand as well as site-specific degree-day sum (temperature), water balance, and plant-available water holding capacity. We grouped tree species to facilitate comparisons between species with different levels of tolerance to shade and drought.Basal area and shade casting ability of the overstory had generally a negative impact on tree recruitment, but the effects differed between levels of shade tolerance of tree recruitment in all study regions. Recruitment rates of very shade-tolerant species were positively affected by shade casting ability. Stem density and summer warmth (degree-day sum) had similar effects on all tree species and successional strategies. Water-related variables revealed a high degree of uncertainty and did not allow for general conclusions. All variables had similar effects independent of the varying diameter thresholds for tree recruitment in the different data sets.Synthesis: Shade tolerance and stand structure are the main drivers of tree recruitment along wide environmental gradients in temperate forests. Higher temperature generally increases tree recruitment rates, but the role of water relations and drought tolerance remains uncertain for tree recruitment on cross-regional scales.

Influence of high density planting and spatial arrangement on growth and development in Musa AAA Simmonds / Influencia de altas densidades de siembra y distribución espacial sobre el crecimiento y desarrollo en Musa AAA Simmonds

ABSTRACT Banana is after apple, the most consumed fruit in the world for its nutritional contribution. Given its importance, it is necessary to advance in the development of agronomic management strategies that contribute to increase productivity and offer alternatives to regulate the consequences derived from the seasonality of production in the Urabá area (Colombia). For this, the clone Williams (Musa AAA Simmonds), at different planting densities (2000, 2500, 3000 and 3500 plants ha-1), different population arrangements (triangle, rectangle and double furrow), compared with a relative control (1700 plants ha-1 in triangle) was evaluated. The design used was randomized complete blocks in factorial arrangement of 4 x 3 + 1 (densities x arrays + control). The variables height and perimeter of the pseudostem, number of leaves from planting to harvest, leaf area index (IAF), light extinction coefficient, number of suckers and developmental stages (days elapsed after flowering and harvest) were determined. An analysis of general variance was carried out and another one excluding the control. The Tukey test (P <0.05) was applied to the qualitative variables and contrasts of orthogonal polynomials were made to test the linear and quadratic effects of the population density factor. The results indicated that the high planting densities and the population arrangements had a negative effect on the perimeter of the pseudostem and the height of the main sucker, favored the LAI, influenced the extinction coefficient, but did not affect the development of the plants.

RESUMEN El banano es después de la manzana la fruta más consumida en el mundo, por su aporte nutricional. Dada su importancia, se requiere avanzar en el desarrollo de estrategias de manejo agronómico, que contribuyan a incrementar la productividad y ofrezcan alternativas para regular las consecuencias derivadas de la estacionalidad de la producción, en la zona del Urabá (Colombia). Para ello, se evaluaron en el clon Williams (Musa AAA Simmonds), diferentes densidades de plantación (2.000, 2.500, 3.000 y 3.500 plantas ha-1), distintos arreglos poblacionales (triángulo, rectángulo y doble surco) y un testigo relativo (1.700 plantas ha-1 en triángulo). El diseño utilizado fue de bloques completos al azar en arreglo factorial, de 4 x 3 + 1 (densidades x arreglos + testigo). Se determinaron la altura y perímetro del pseudotallo, el número de hojas de siembra a cosecha, el índice de área foliar (IAF), el coeficiente de extinción de luz, el número de hijos y fases de desarrollo: días transcurridos a floración y cosecha. Se realizó un análisis de varianza general y otro excluyendo el testigo. Se aplicó la prueba de Tukey (P<0,05) a las variables cualitativas y se hicieron contrastes de polinomios ortogonales, para probar los efectos lineal y cuadrático del factor densidad de población. Los resultados indicaron que las altas densidades de plantación y los arreglos poblacionales tuvieron un efecto negativo sobre el perímetro del pseudotallo y la altura del hijo a parición, favorecieron el IAF, influyeron en el coeficiente de extinción, pero no afectaron el desarrollo de las plantas.

A multilayered cross-species analysis of GRAS transcription factors uncovered their functional networks in plant adaptation to the environment.

Introduction: Environmental stress is both a major force of natural selection and a prime factor affecting crop qualities and yields. The impact of the GRAS [gibberellic acid-insensitive (GAI), repressor of GA1-3 mutant (RGA), and scarecrow (SCR)] family on plant development and the potential to resist environmental stress needs much emphasis. Objectives: This study aims to investigate the evolution, expansion, and adaptive mechanisms of GRASs of important representative plants during polyploidization. Methods: We explored the evolutionary characteristics of GRASs in 15 representative plant species by systematic biological analysis of the genome, transcriptome, metabolite, protein complex map and phenotype. Results: The GRAS family was systematically identified from 15 representative plant species of scientific and agricultural importance. The detection of gene duplication types of GRASs in all species showed that the widespread expansion of GRASs in these species was mainly contributed by polyploidization events. Evolutionary analysis reveals that most species experience independent genome-wide duplication (WGD) events and that interspecies GRAS functions may be broadly conserved. Polyploidy-related Chenopodium quinoa GRASs (CqGRASs) and Arabidopsis thaliana GRASs (AtGRASs) formed robust networks with flavonoid pathways by crosstalk with auxin and photosynthetic pathways. Furthermore, Arabidopsis thaliana population transcriptomes and the 1000 Plants (OneKP) project confirmed that GRASs are components of flavonoid biosynthesis, which enables plants to adapt to the environment by promoting flavonoid accumulation. More importantly, the GRASs of important species that may potentially improve important agronomic traits were mapped through TAIR and RARGE-II publicly available phenotypic data. Determining protein interactions and target genes contributes to determining GRAS functions. Conclusion: The results of this study suggest that polyploidy-related GRASs in multiple species may be a target for improving plant growth, development, and environmental adaptation.

Development of a Methodology for Maintenance of Medicinal Plant Genetic Reserve Sites: A Case Study for Lithuania.

In the context of climate change, in situ conservation of plant genetic resources is becoming increasingly important as it supports natural (ecological and evolutionary) adaptations of plants to the changing environment. The aim of this study was to synthesize a comprehensive general methodology for the maintenance of genetic reserve sites of medicinal plants based on the analysis of relevant legal documents, literature sources, databases, and authors' own experience. A methodology was developed for the application of various maintenance measures for target species populations in genetic reserve sites to ensure their long-term sustainability. It uses a systematic approach to the intervention measures by grouping them into habitat-specific and factor-specific ones, and follows the specific principles of biodiversity conservation, such as the concept of ecosystem, priority of in situ conservation, caution and validity of decision-making, and regional approach. An extensive discussion on major intervention measures is provided. The methodology is intended to be used as a tool for the preparation and implementation of management plans of individual medicinal plant genetic reserve sites by the responsible agencies and protected area managers and is directly linked to the implementation of the EU (European Union) Biodiversity Strategy to 2030 at the national level.