Separating the effects of partial submergence and soil oxugen demand on plant physiology.

In wetlands, a distinct zonation of plant species composition occurs along moisture gradients, due to differential flooding tolerance of the species involved. However, "flooding" comprises two important, distinct stressors (soil oxygen demand [SOD] and partial submergence) that affect plant survival and growth. To investigate how these two flooding stressors affect plant performance, we executed a factorial experiment (water depth x SOD) for six plant species of nutrient-rich and nutrient-poor conditions, occurring along a moisture gradient in Dutch dune slacks. Physiological, growth, and biomass responses to changed oxygen availability were quantified for all species. The responses were consistent with field zonation, but the two stressors affected species differently. Increased SOD increased root oxygen deprivation, as indicated by either raised porosity or increased alcohol dehydrogenase (ADH) activity in roots of flood-intolerant species (Calamagrostis epigejos and Carex arenaria). While SOD affected root functioning, partial submergence tended more to reduce photosynthesis (as shown both by gas exchange an

Phylogenetic diversity shapes salt tolerance in Phragmites australis estuarine populations in East China

Estuaries are dynamic and selective environments that provide frequent opportunities for the turnover of Phragmites australis populations. We studied Phragmites genetic diversity patterns in three of the major deltas of China, viz. the Yellow River, the Yangtze and the Liaohe, in relation to Phragmites global phylogeography and soil salinity. We found that two distantly related P. australis haplotypes, each with intercontinental distribution, co-occur in these deltas in China. One is European Phragmites (Haplotype O) and is related to P. japonicus; the other (Haplotype P) has its range in East Asia and Australia and is related to the Asian tropical species P. karka. The two haplotypes have differing salt tolerance, with Haplotype O in areas with the highest salinity and Haplotype P in areas with the lowest. Introgressed hybrids of Haplotype P with P. karka, and F1 hybrids with Haplotype O, have higher salt tolerance than Haplotype P. Phylogenetic diversity appears as the factor that better explains population structure and salinity tolerance in these estuaries. Future research may explain whether the two P. australis haplotypes evolved in East Asia, and East Asia is a center of Phragmites diversity, or are introduced and a threat to P. japonicus and P. karka

How the decarbonisation discourse may lead to a reduced set of policy options for climate policies in Europe in the 2020s

Centered on molecule-based energy carriers, policy challenges of phase-two Energy Transition (ET2) differ significantly from the electricity-centric ones (ET1) met by Europe so far. Calls for full electrification and frames shaped by notions of ‘renewable’, ‘green’, ‘ambition’ and ‘net-zero decarbonisation’ suggest that ‘lock-ins’ may emerge not only from (by now well-researched) incumbent strategies but also from advocacy discourses inherited from ET1. With power and knowledge inextricably conjoined, discourses co-construct the policy agenda. To succeed with ET2, Europe must develop a reflexive, multi-level and interdisciplinary strategy that covers the techno-economic-behavioral dimensions and the influence of discourses on policy formulation. By using discourse analysis and discursive institutionalism as an anchor for cognitive neuroscience and for the relevant social science and political science, ET research can consider how science-based and emotion-driven perspectives interbreed in policy and discourse complexes. How shared conceptual spaces are contested can help improve the reflexivity of ET research as well as provide insights on opposition. A keener understanding of two-way interaction between policies and discourses will help free ET2 policies from ET1 lock-ins