Mistletoes have higher hydraulic safety but lower efficiency in xylem traits than their hosts.

Both mistletoes and their hosts are challenged by increasing drought, highlighting the necessity of understanding their comparative hydraulic properties. The high transpiration of mistletoes requires efficient water transport, while high xylem tensions demand strong embolism resistance, representing a hydraulic paradox. This study, conducted across four environments with different aridity indices in Yunnan, China, examined the xylem traits of 119 mistletoe-host species pairs.

Stimulated photosynthesis of regrowth after fire in coastal scrub vegetation: increased water or nutrient availability?

Fire-prone landscapes experience frequent fires, disrupting above-ground biomass and altering below-ground soil nutrient availability. Augmentation of leaf nutrients or leaf water balance can both reduce limitations to photosynthesis and facilitate post-fire recovery in plants. These modes of fire responses are often studied separately and hence are rarely compared.

Microbial competition for phosphorus limits the CO response of a mature forest.

The capacity for terrestrial ecosystems to sequester additional carbon (C) with rising CO concentrations depends on soil nutrient availability. Previous evidence suggested that mature forests growing on phosphorus (P)-deprived soils had limited capacity to sequester extra biomass under elevated CO (refs. ), but uncertainty about ecosystem P cycling and its CO response represents a crucial bottleneck for mechanistic prediction of the land C sink under climate change.

The AusTraits plant dictionary.

Traits with intuitive names, a clear scope and explicit description are essential for all trait databases. The lack of unified, comprehensive, and machine-readable plant trait definitions limits the utility of trait databases, including reanalysis of data from a single database, or analyses that integrate data across multiple databases. Both can only occur if researchers are confident the trait concepts are consistent within and across sources.

Decoupling between stomatal conductance and photosynthesis occurs under extreme heat in broadleaf tree species regardless of water access.

High air temperatures increase atmospheric vapor pressure deficit (VPD) and the severity of drought, threatening forests worldwide. Plants regulate stomata to maximize carbon gain and minimize water loss, resulting in a close coupling between net photosynthesis (A ) and stomatal conductance (g ). However, evidence for decoupling of g from A under extreme heat has been found.

Similar patterns of leaf temperatures and thermal acclimation to warming in temperate and tropical tree canopies.

As the global climate warms, a key question is how increased leaf temperatures will affect tree physiology and the coupling between leaf and air temperatures in forests. To explore the impact of increasing temperatures on plant performance in open air, we warmed leaves in the canopy of two mature evergreen forests, a temperate Eucalyptus woodland and a tropical rainforest. The leaf heaters consistently maintained leaves at a target of 4 °C above ambient leaf temperatures.

Stomatal responses of terrestrial plants to global change.

Quantifying the stomatal responses of plants to global change factors is crucial for modeling terrestrial carbon and water cycles. Here we synthesize worldwide experimental data to show that stomatal conductance (g) decreases with elevated carbon dioxide (CO), warming, decreased precipitation, and tropospheric ozone pollution, but increases with increased precipitation and nitrogen (N) deposition. These responses vary with treatment magnitude, plant attributes (ambient g, vegetation biomes, and plant functional types), and climate.

You are what you eat: nutrient and water relations between mistletoes and hosts.

Mistletoes play important roles in biogeochemical cycles. Although many studies have compared nutrient concentrations between mistletoes and their hosts, no general patterns have been found and the nutrient uptake mechanisms in mistletoes have not been fully resolved. To address the water and nutrient relations in mistletoes compared with their hosts, we measured 11 nutrient elements, two isotope ratios and two leaf morphological traits for 11 mistletoe and 104 host species from four sites across a large environmental gradient in southwest China.

Optimal stomatal theory predicts CO responses of stomatal conductance in both gymnosperm and angiosperm trees.

Optimal stomatal theory predicts that stomata operate to maximise photosynthesis (A ) and minimise transpirational water loss to achieve optimal intrinsic water-use efficiency (iWUE). We tested whether this theory can predict stomatal responses to elevated atmospheric CO (eCO ), and whether it can capture differences in responsiveness among woody plant functional types (PFTs). We conducted a meta-analysis of tree studies of the effect of eCO on iWUE and its components A and stomatal conductance (g ).

Convergence in phosphorus constraints to photosynthesis in forests around the world.

Tropical forests take up more carbon (C) from the atmosphere per annum by photosynthesis than any other type of vegetation. Phosphorus (P) limitations to C uptake are paramount for tropical and subtropical forests around the globe. Yet the generality of photosynthesis-P relationships underlying these limitations are in question, and hence are not represented well in terrestrial biosphere models.

Crown dieback and mortality of urban trees linked to heatwaves during extreme drought.

Cities have been described as 'heat islands' and 'dry islands' due to hotter, drier air in urban areas, relative to the surrounding landscape. As climate change intensifies, the health of urban trees will be increasingly impacted. Here, we posed the question: Is it possible to predict urban tree species mortality using (1) species climate envelopes and (2) plant functional traits? To answer these, we tracked patterns of crown dieback and recovery for 23 common urban tree and shrub species in Sydney, Australia during the record-breaking austral 2019-2020 summer.

Predicting resilience through the lens of competing adjustments to vegetation function.

There is a pressing need to better understand ecosystem resilience to droughts and heatwaves. Eco-evolutionary optimization approaches have been proposed as means to build this understanding in land surface models and improve their predictive capability, but competing approaches are yet to be tested together. Here, we coupled approaches that optimize canopy gas exchange and leaf nitrogen investment, respectively, extending both approaches to account for hydraulic impairment.

Extreme heat increases stomatal conductance and drought-induced mortality risk in vulnerable plant species.

Tree mortality during global-change-type drought is usually attributed to xylem dysfunction, but as climate change increases the frequency of extreme heat events, it is necessary to better understand the interactive role of heat stress. We hypothesized that some drought-stressed plants paradoxically open stomata in heatwaves to prevent leaves from critically overheating. We experimentally imposed heat (>40°C) and drought stress onto 20 broadleaf evergreen tree/shrub species in a glasshouse study.

Is photosynthetic enhancement sustained through three years of elevated CO2 exposure in 175-year-old Quercus robur?

Current carbon cycle models attribute rising atmospheric CO2 as the major driver of the increased terrestrial carbon sink, but with substantial uncertainties. The photosynthetic response of trees to elevated atmospheric CO2 is a necessary step, but not the only one, for sustaining the terrestrial carbon uptake, but can vary diurnally, seasonally and with duration of CO2 exposure. Hence, we sought to quantify the photosynthetic response of the canopy-dominant species, Quercus robur, in a mature deciduous forest to elevated CO2 (eCO2) (+150 μmol mol-1 CO2) over the first 3 years of a long-term free air CO2 enrichment facility at the Birmingham Institute of Forest Research in central England (BIFoR FACE).

Differentiation in stem and leaf traits among sympatric lianas, scandent shrubs and trees in a subalpine cold temperate forest.

The scandent shrub plant form is a variant of liana that has upright and self-supporting stems when young but later becomes a climber. We aimed to explore the associations of stem and leaf traits among sympatric lianas, scandent shrubs and trees, and the effects of growth form and leaf habit on variation in stem or leaf traits. We measured 16 functional traits related to stem xylem anatomy, leaf morphology and nutrient stoichiometry in eight liana, eight scandent shrub and 21 tree species co-occurring in a subalpine cold temperate forest at an elevation of 2600-3200 m in Southwest China.

Increasing aridity will not offset CO fertilization in fast-growing eucalypts with access to deep soil water.

Rising atmospheric [CO ] (C ) generally enhances tree growth if nutrients are not limiting. However, reduced water availability and elevated evaporative demand may offset such fertilization. Trees with access to deep soil water may be able to mitigate such stresses and respond more positively to C .

Canopy position affects photosynthesis and anatomy in mature Eucalyptus trees in elevated CO2.

Leaves are exposed to different light conditions according to their canopy position, resulting in structural and anatomical differences with consequences for carbon uptake. While these structure-function relationships have been thoroughly explored in dense forest canopies, such gradients may be diminished in open canopies, and they are often ignored in ecosystem models. We tested within-canopy differences in photosynthetic properties and structural traits in leaves in a mature Eucalyptus tereticornis canopy exposed to long-term elevated CO2 for up to three years.

Low phosphorus supply constrains plant responses to elevated CO : A meta-analysis.

Phosphorus (P) is an essential macro-nutrient required for plant metabolism and growth. Low P availability could potentially limit plant responses to elevated carbon dioxide (eCO ), but consensus has yet to be reached on the extent of this limitation. Here, based on data from experiments that manipulated both CO and P for young individuals of woody and non-woody species, we present a meta-analysis of P limitation impacts on plant growth, physiological, and morphological response to eCO .

Implementing Living Independent From Tobacco With Dyads of People With Disabilities and Their Caregivers: Successes and Lessons Learned.

People with disabilities have more health complications and higher healthcare utilization related to tobacco use than people without disabilities. Yet, they are less likely to use tobacco cessation resources. Important to meaningful and lasting health behavior change are relationships developed in the home, workplace, and community.

The fate of carbon in a mature forest under carbon dioxide enrichment.

Atmospheric carbon dioxide enrichment (eCO) can enhance plant carbon uptake and growth, thereby providing an important negative feedback to climate change by slowing the rate of increase of the atmospheric CO concentration. Although evidence gathered from young aggrading forests has generally indicated a strong CO fertilization effect on biomass growth, it is unclear whether mature forests respond to eCO in a similar way. In mature trees and forest stands, photosynthetic uptake has been found to increase under eCO without any apparent accompanying growth response, leaving the fate of additional carbon fixed under eCO unclear.

Global response patterns of plant photosynthesis to nitrogen addition: A meta-analysis.

A mechanistic understanding of plant photosynthetic response is needed to reliably predict changes in terrestrial carbon (C) gain under conditions of chronically elevated atmospheric nitrogen (N) deposition. Here, using 2,683 observations from 240 journal articles, we conducted a global meta-analysis to reveal effects of N addition on 14 photosynthesis-related traits and affecting moderators. We found that across 320 terrestrial plant species, leaf N was enhanced comparably on mass basis (N , +18.

Opioid Use Disorder and Employee Work Presenteeism, Absences, and Health Care Costs.

Objective: To measure the prevalence of opioid use disorder (OUD) and employee health care and productivity costs with and without OUD and to assess whether utilization of pharmacotherapy for OUD reduces those costs.

Methods: We conducted a cross-sectional analysis of 2016 to 2017 commercial enrollment, health care, and pharmacy claims and health risk assessment data using the IBM MarketScan Databases (Ann Arbor, MI). We estimated regression models to assess the association between OUD and annual employee health care and productivity costs.