Plant responses to decadal scale increments in atmospheric CO2 concentration: comparing two stomatal conductance sampling methods

There are several lines of evidence suggesting that the vast majority of C3 plants respond to elevated atmospheric CO2 by decreasing their stomatal conductance (gs). However, in the majority of CO2 enrichment studies, the response to elevated CO2 are tested between plants grown under ambient (380–420 ppm) and high (538–680 ppm) CO2 concentrations and measured usually at single time points in a diurnal cycle. We investigated gs responses to simulated decadal increments in CO2 predicted over the next 4 decades and tested how measurements of gs may differ when two alternative sampling methods are employed (infrared gas analyzer [IRGA] vs. leaf porometer). We exposed Populus tremula, Popolus tremuloides and Sambucus racemosa to four different CO2 concentrations over 126 days in experimental growth chambers at 350, 420, 490 and 560 ppm CO2; representing the years 1987, 2025, 2051, and 2070, respectively (RCP4.5 scenario). Our study demonstrated that the species respond non-linearly to increases in CO2 concentration when exposed to decadal changes in CO2. Under natural conditions, maximum operational gs is often reached in the late morning to early afternoon, with a mid-day depression around noon. However, we showed that the daily maximum gs can, in some species, shift later into the day when plants are exposed to only small increases (70 ppm) in CO2. A non-linear decreases in gs and a shifting diurnal stomatal behavior under elevated CO2, could affect the long-term daily water and carbon budget of many plants in the future, and therefore alter soil–plant–atmospheric processes.Irish Research CouncilScience Foundation Irelan

Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

Background Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories. Methods We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5–19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI <18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For schoolaged children and adolescents, we report thinness (BMI <2 SD below the median of the WHO growth reference) and obesity (BMI >2 SD above the median). Findings From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness. Interpretation The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesit

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses

To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely

Teaching and assessment strategies for active student learning in university horticultural education

Many of the goals of the university teacher today are to enthuse, drive and challenge students academically, intellectually and personally; to advance their capacity for critical thinking, judgement and communication; and to equip them with sufficient scientific and technical knowledge to make them competent horticultural practitioners. Given that most programme modules are delivered by lectures, there is general consensus that student learning is primarily passive. Similarly, module assessment tends to be summative. Thus, student-centred learning to foster an environment for active learning and encourage greater student class participation was introduced into a horticulture module (Nursery Production and Management HORT 40090). Similarly, formative assessment methods were also introduced. To this end, a segment of the above module relating to vegetative plant propagation was selected. The students were asked to work in self selected groups to thoroughly research the different aspects of the topic and to prepare a short PowerPoint slide presentation for delivery to the class. Additionally, they were required to peer assess each presentation and to agree a suitable grade with staff members in attendance. It is considered that the introduction of active learning and formative assessment to the module resulted in more meaningful learning for the students concerned and moved them higher up the student-centred learning curve towards more, responsibility and accountability. The concept is being gradually rolled out to other modules

Introducing landscape design techniques to horticulture students

Students majoring in Horticulture Landscape and Sportsturf Management take an introductory module in Landscape Design. During a seven week period through a series of lectures, studio based graphic and design exercises, and site visits students are introduced to landscape design principles. Following an introduction to garden history each student prepares a precedent study based on the work of an international landscape designer. Furthermore, they must prepare a domestic or commercial landscape design plan. In the last academic year the class was invited to develop landscape design proposals for Beech Hill College in Monaghan. Ordnance survey maps of the site were obtained in preparation for the site visit and meeting with the School Principal who outlined the specific requirements. The students were sub-divided into three working groups and assigned a specific area of the school campus to survey and evaluate existing vegetation. Each student created design proposals, drew cross sections and a planting plan for their areas. At the end of the semester each student presented their work to peers, staff and the School Principal and was given immediate feedback. Student response to the project was highly positive and in comparison to previous years, the design proposals were suitable for implementation. Students participated in individual and group work, developed critical thinking skills, presentation skills, and all transferable skills required of university graduates. Engaging in a 'live' project for a school campus emphasised their contribution to a local community. The students have been invited to return and to further develop the site

Benefits of Scenario-based Learning in university education

As an applied science, horticulture is particularly suited to interactive teaching and learning methods.  Much of the undergraduate learning in horticulture is passive; therefore, more active learning strategies should be introduced. One such active learning technique is scenario-based learning (SBL).  This form of learning allows students to apply academic knowledge to a simulated 'real-life' situation.  It is particularly suited to promoting group participation and learning.  Its use provides students with the opportunity to recognise and solve problems, to think critically and to develop teamwork skills.  Recently, an SBL project was introduced to the Fruit Production (HORT30190) undergraduate module at University College Dublin.  In order to implement the project, the class was divided into groups and each group was required to establish a hypothetical commercial dessert, culinary or cider apple orchard in Ireland.  The groups were required to consider site characteristics, growing and pruning systems, rootstocks, cultivars, pollinator selection and planting density. They presented their results in class using posters and submitted a personal learning journal associated with the project, both of which were assessed by staff. Student response to the SBL project was evaluated for benefits such as increased understanding of course material, acquisition of transferable skills and enjoyment of the learning method. This project is an example of formative assessment in action.  Scenario-based learning allows students to contextualise learning while acquiring transferable skills.  It is suitable for implementation in a wide range of diverse university modules.European Research CouncilUniversity College Dubli

Searching for a nearest living equivalent for Bennettitales: a promising extinct plant group for stomatal proxy reconstructions of Mesozoic pCO2

To understand Earth ́s climate variability and improve predictions of future climate change, studying past climates is an important avenue to explore. A previously published record of pCO2, across the Triassic–Jurassic boundary (TJB, ~201 Ma) of East Greenland, showed that Bennettitales (Anamozamites and Pterophyllum) responded in parallel to the empirically proven pCO2-responders Ginkgoales, reducing their stomatal densities by half across the TJB, indicating a transient doubling of pCO2. The abundance of fossil Bennettitales in Mesozoic strata and natural history museum collections worldwide offers enormous potential for further stomatal proxy pCO2 reconstructions, but a suitable nearest living equivalent (NLE) should ideally first be identified for this extinct plant group. Using specimens from herbarium collections, three species of cycads, historically considered the best NLE, were tested for pCO2 response, as well as two species of tree ferns, grown in experimental growth chambers. None responded to changes in pCO2, and were consequently rejected as NLEs. Finally, two species of ferns were selected from the literature, and produced very similar pCO2 compared to Ginkgoales. However, these understory ferns are not appropriate NLEs for Bennettitales due to differences in habitat and a distant evolutionary relationship. Future work should test additional plant groups, in particular seed plants such as basal angiosperms and Gnetales, for suitability as NLE for Bennettitales in pCO2 reconstructions, for example through biogeo- chemical fingerprinting using infrared microspectroscopy. Until an appropriate NLE is identified, Bennettitales pCO2 can be reconstructed based on cross-calibration of stomatal densities with those of co-occurring pCO2 responders, such as Ginkgoales.This work was supported by the EU Marie Curie Excellence Grant (MEXT-CT-2006-042531) to J.McE and M.S., the Swedish Research Council (VR Starting Grant NT-7 2016 04905) to M.S., and the IRCSET Embark scholarship (R10679) to C.E-K. We also gratefully acknowledge funding from the EU Marie Curie Intra-European Fellowship (PEA-IEF-2010-275626) and ERC grant (ERC-279962-OXYEVOL). We thank the following for technical assistance: Bredagh Moran, UCD; Matthew Gilroy, Conviron UK; Aidan Blake, Aaron Refrigeration Ireland. </p

Co-ordination in morphological leaf traits of early diverging angiosperms is maintained following exposure to experimental palaeoatmospheric conditions of sub-ambient O2 and elevated CO2

In order to be successful in a given environment a plant should invest in a vein and stomatal network that ensures balance between both water supply and demand. Vein density (Dv) and stomatal density (SD) have been shown to be strongly positively correlated in response to a range of environmental variables in more recently evolved plant species, but the extent of this relationship has not been confirmed in earlier diverging plant lineages. In order to examine the effect of a changing atmosphere on the relationship between Dv and SD, five early-diverging plant species representing two different reproductive plant grades were grown for seven months in a palaeo-treatment comprising an O2:CO2 ratio that has occurred multiple times throughout plant evolutionary history. Results show a range of species-specific Dv and SD responses to the palaeo-treatment, however we show that the strong relationship between Dv and SD under modern ambient atmospheric composition is maintained following exposure to the palaeo-treatment. This suggests strong co-ordination between vein and stomatal traits even under relatively extreme environmental change. This co-ordination supports existing plant function proxies that use the distance between vein endings and stomata (Dm) to infer plant palaeo-physiology such as assimilation rate, and as a result, lends confidence to future application of palaeo-CO2 proxy models that require robust estimates of palaeo-assimilation rate as key initialisation parameters. European Research Counci

Co-ordination in morphological leaf traits of early diverging angiosperms is maintained following exposure to experimental palaeo-atmospheric conditions of sub-ambient O2 and elevated CO2

In order to be successful in a given environment a plant should invest in a vein network and stomatal distribution that ensures balance between both water supply and demand. Vein density (Dv) and stomatal density (SD) have been shown to be strongly positively correlated in response to a range of environmental variables in more recently evolved plant species, but the extent of this relationship has not been confirmed in earlier diverging plant lineages. In order to examine the effect of a changing atmosphere on the relationship between Dv and SD, five early-diverging plant species representing two different reproductive plant grades were grown for seven months in a palaeo-treatment comprising an O2:CO2 ratio that has occurred multiple times throughout plant evolutionary history. Results show a range of species-specific Dv and SD responses to the palaeo-treatment, however we show that the strong relationship between Dv and SD under modern ambient atmospheric composition is maintained following exposure to the palaeo-treatment. This suggests strong inter-specific co-ordination between vein and stomatal traits for our study species even under relatively extreme environmental change. This co-ordination supports existing plant function proxies that use the distance between vein endings and stomata (Dm) to infer plant palaeo-physiology