Methyl salicylate as a signaling compound that contributes to forest ecosystem stability

Methyl salicylate (MeSA) is a volatile plant and microbial signaling compound involved in systemic acquired resistance (SAR) and defense against pests and microbial pathogens, and antagonists. MeSA emitted by plants is also believed to trigger SAR in neighboring plant individuals, thus contributing to the resilience of the entire plant community. In this review, we discuss volatile plant-to-plant communication processes with a special focus on MeSA and provide an overview about the occurrence of MeSA in fungi and other microbes. We summarize present findings on the role of MeSA in plants and particularly in birches (Betula spp.) and discuss the potential use of MeSA and MeSA-emitting plants in agriculture and forestry. MeSA levels in plant tissues are adjusted by methylation of salicylic acid to MeSA and the reverse process of demethylation. Some plant species possess constitutively high MeSA levels and thus are suitable for experiments of admixture of high MeSA plants, e.g., birches of the subgenera Betulenta and Acuminata in plant communities such as mixed forests. Furthermore, knowledge of candidate genes and the molecular pathways underlying high MeSA emission is expected to offer a basis for altering MeSA levels and/or the selection of high MeSA mutants.Humboldt-Universität zu Berlin (1034)Peer Reviewe

Methyl salicylate as a signaling compound that contributes to forest ecosystem stability

Methyl salicylate (MeSA) is a volatile plant and microbial signaling compound involved in systemic acquired resistance (SAR) and defense against pests and microbial pathogens, and antagonists. MeSA emitted by plants is also believed to trigger SAR in neighboring plant individuals, thus contributing to the resilience of the entire plant community. In this review, we discuss volatile plant-to-plant communication processes with a special focus on MeSA and provide an overview about the occurrence of MeSA in fungi and other microbes. We summarize present findings on the role of MeSA in plants and particularly in birches (Betula spp.) and discuss the potential use of MeSA and MeSA-emitting plants in agriculture and forestry. MeSA levels in plant tissues are adjusted by methylation of salicylic acid to MeSA and the reverse process of demethylation. Some plant species possess constitutively high MeSA levels and thus are suitable for experiments of admixture of high MeSA plants, e.g., birches of the subgenera Betulenta and Acuminata in plant communities such as mixed forests. Furthermore, knowledge of candidate genes and the molecular pathways underlying high MeSA emission is expected to offer a basis for altering MeSA levels and/or the selection of high MeSA mutants

(Un)expected Learning Outcomes of Virtual School Garden Exchanges in the Field of Education for Sustainable Development

Global solidarity is paramount in times of global crises and essential in Education for Sustainable Development (ESD). Virtual School Garden Exchanges (VSGEs) link local gardening with global thinking. In VSGEs, elementary and secondary school students in different parts of the world exchange information about their school gardens and related topics via digital media. Educators’ perspectives and the learning outcomes they observed in the participants of the VSGEs were the focus of this study, as there has been controversy about whether VSGEs are suitable for implementing ESD and whether VSGEs result in the learning outcomes that the educators expect them to. We conducted 20 semi-structured interviews with VSGE educators and analyzed them in an abductive and qualitative manner. The results showed substantial overlap with both the expected learning outcomes and the aims of ESD. Nevertheless, the data revealed different ways in which learners who engaged with their international peers were influenced by stereotypes and norms. On the one hand, VSGEs can lead to Othering, which is not congruent with either ESD or the expected learning outcomes. On the other hand, it can inspire Transformative Learning processes, which contribute to the aims of ESD. Therefore, depending on a complex interplay of various factors, there is potential for ESD in VSGEs, but VSGEs are not guaranteed to be a good ESD practice.Peer Reviewe

Soil degradation and herbicide pollution by repeated cassava monoculture within Thailand’s conservation region

In a national park in Northeast Thailand, agricultural land has been converted from natural forest by small-scale farmers for cassava agriculture. We hypothesise that long-termed cassava monoculture leads to the degradation of soil properties. To test the hypothesis, we conducted a five-year (2016–2020) study on the physical and chemical properties of soil in cassava farmland, and also examined the soil properties of its adjacent natural forests, as a control. The examined cassava farmland was converted from the natural forest during the five years from 2011 to 2015. The significant decrease in organic carbon and the increases in exchangeable potassium and bulk density were found in 2016, indicating that these soil properties varied quickly following the farmland conversion. On the other hand, the significant increase in soil nitrogen and the decrease in pH were found later in 2020, indicating that these soil properties were gradually altered by repeated agricultural activities, such as fertilizer application and trampling. In contrast, there were no significant differences in available phosphate, electrical conductivity, cation exchange capacity, and the soil texture (the fractions of sand, silt, and clay) among the forest and farmland soils. The cation exchange capacity was positively correlated to the fraction of clay, the organic carbon, and pH. The use of glyphosate and paraquat herbicides is prohibited within national parks in Thailand. However, in 2020, glyphosate was detected in farmland soil (up to 5.0 mg kg⁻¹) during both the rainy and dry seasons, and glyphosate (up to 2.5 mg l⁻¹) was detected in stream water from the farmland during the dry season at least in 2020. Soil degradation and herbicide pollution may carry a high risk of causing irreversible changes in terrestrial ecosystems. We discuss the root causes of this issue from perspectives of agricultural production, economy, and the environmental impact, and propose effective policy measures

Green Brains & Ground Sloths: A Paleoecology-Based Exercise in Hypothesis Formation

In organismic biology, the formation of ecological and evolutionary hypotheses on the basis of observable morphologies is a central element of research, and by extension of teaching and learning. Often it is necessary to take account of complex combinations of factors, some of which may be far from obvious. In the work described here, hypothesis formation and testing was exercised and studied in a learner-centered and object-based manner using an anachronistic, seemingly “nonsensical” plant, Maclura pomifera (Moraceae), in which the link between structure and function only becomes clear when considering past faunistic environments. The element of the unexpected and the allure of the large animals is thought to add to epistemic curiosity and student motivation to engage in the study of plants.</jats:p

Surface-Area-to-Volume Ratios, Fluid Dynamics &amp; Gas Diffusion: Four Frogs &amp; Their Oxygen Flux

Processes of diffusion of oxygen can be described in a formalized and simplified manner in formulas such as Fick's laws of diffusion. For a sound understanding of the interconnections of anatomical structure, biological function, and environmental factors in a living system, however, real-life case studies need to be employed to explore what is captured in the equation and what is not, and which other structures and behaviors may play a role in respiratory physiology. I use four anuran examples to illustrate, starting with Fick's first law, respiratory processes as influenced by surface-area-to-volume ratio and turbulence in the surrounding medium.</jats:p

Blue Tigers, Black Tapirs, &amp; the Pied Raven of the Faroe Islands

Genetic drift is a concept of population genetics that is central to understanding evolutionary processes and aspects of conservation biology. It is frequently taught using rather abstract representations. I introduce three real-life zoological examples, based on historical and recent color morphs of tigers, tapirs, and ravens, that can complement classical models.</jats:p

Smells Like Science: Olfactory Exploration of the Biosphere

This article discusses the alluring topic of olfactory learning, which is often touched on in the literature but is rarely employed. I argue that olfactory learning, at its best, is achieved in contact with living nature, as in the plethora of scents that can be encountered and discussed in ecological context in a forest. An expected outcome is enhanced sensory awareness of the living environment.</jats:p