Tagged: Elevated CO2



Savannah

Savanna tree and C4 grass acclimation responses across low-to-high CO2

By the year 2100, atmospheric CO2 concentration ([CO2]a) could reach 800 ppm, having risen from ~200 ppm since the Neogene, beginning ~24 Myr ago. Changing [CO2]a affects plant carbon–water balance, with implications for growth, drought tolerance and vegetation shifts. The evolution of C4 photosynthesis improved plant hydraulic function under low [CO2]a and preluded the establishment of savannahs, characterized by rapid transitions between open C4-dominated grassland with scattered trees and closed forest. Understanding directional vegetation trends in response to environmental change will require modelling. But models are often parameterized with characteristics observed in plants under current climatic conditions, necessitating experimental quantification...

Continue reading Savanna tree and C4 grass acclimation responses across low-to-high CO2

Warming and elevated CO2 alter the suberin chemistry in roots

The decomposability of fine roots and their potential to contribute to soil carbon (C) is partly regulated by their tissue chemical composition. In a recent Editor’s Choice article published in AoB PLANTS, Suseela et al. examined the effects of elevated CO2 and warming on the quantity and composition of suberin in the roots of a C4 and C3 grass species. Elevated CO2 and warming altered the content and composition of suberin in roots of the C4 species, which could alter the rate of root decomposition. However, suberin in the C3 species was less responsive to climate treatments, suggesting that climate...

Continue reading Warming and elevated CO2 alter the suberin chemistry in roots


Experimental set-up

Mitigating effects of well-timed rainfall on plant mortality

Global warming accelerates plant water use, increasing plant susceptibility to drought death. From this, it can be hypothesised that higher CO2 concentrations slow plant water use, and should offset the warming effects on mortality. Using six years of data from a field experiment, Hovenden et al. demonstrate that the timing of rainfall has a major influence on the impacts of warming and elevated CO2 on plant mortality. Elevated CO2 moderated the increase in mortality caused by warming, but only in years with few dry spells. The timing of wet spells is shown to be a crucial determinant of how climate...

Continue reading Mitigating effects of well-timed rainfall on plant mortality

Glasshouse showing soda lime column and vacuum pump in foreground (A), seedling of Araucaria heterophylla (B) and (C) seedling of Podocarpus guatemalensis.

Tropical conifer response to altered CO2 concentration

Conifers dominated the lowland tropics 100 million years ago, but have now been largely replaced by angiosperms, coincident with a large decline in atmospheric CO2. Using greenhouse treatments of pre-industrial (280 ppm), ambient (400 ppm) and Eocene (800 ppm) CO2 levels, Dalling et al. demonstrate that seedlings of tropical conifers show stronger growth enhancement with increasing CO2 than angiosperms. The conifers also exhibit greater water-use efficiency (WUE), reflecting both increased photosynthetic rate and reduced stomatal conductance under elevated CO2. High plasticity in photosynthetic and WUE traits may help account for the continued persistence of conifers despite dramatic changes in CO2 levels since the...

Continue reading Tropical conifer response to altered CO2 concentration

大車前草 Plantago asiatica

Competition effects on plastic and genotypic responses to [CO2]

Plant–plant interactions could mediate vegetation responses to rising atmospheric CO2 concentration ([CO2]), because some plants benefit more from [CO2] elevation than others. Van Loon et al. investigated how changes in performance due to elevated [CO2] are modified by aboveground plant–plant interactions. They grew Plantago asiatica seeds originating from natural [CO2] springs and from ambient [CO2] in mono-stands of both origins as well as mixtures of both origins in climate rooms under different [CO2] levels. Their results showed that plant performance to elevated [CO2] was mainly determined by plastic responses and not by genotypic responses. However, this pattern was highly modified...

Continue reading Competition effects on plastic and genotypic responses to [CO2]

The impact of elevated carbon dioxide on the phosphorus nutrition of plants

Plant phosphorus nutrition under elevated CO2 (Review)

Increasing attention is being focused on the influence of rapid increases in atmospheric CO2 concentration on nutrient cycling in ecosystems. An understanding of how elevated CO2 affects plant utilization and acquisition of phosphorus ( P ) will be critical for P management to maintain ecosystem sustainability in P-deficient regions. Jin et al. review possible mechanisms by which elevated CO2 might affect plant P acquisition and conclude that there will be increasing selection pressure for P-acquisition efficiency in a high-carbon environment by plants and plant–microbe associations. Plants will utilize and exploit the increased carbon flow to their roots to more efficiently...

Continue reading Plant phosphorus nutrition under elevated CO2 (Review)

A view over the fynbos

Plants and climate change: complexities and surprises (review)

Camille Parmesan and Mick E. Hanley introduce the special issue with a review of some of the surprises so far with plant responses to anthropogenic climate change. This issue comes from a sponsored symposium session titled Plants and Climate Change: Complexities and Surprises, held during the 99th Ecological Society of America (ESA) meeting in Sacramento, California, in August 2014. The symposium was needed, say Parmesan and Hanley, because there has been an emphasis on ‘big picture’ predictions and responses. What they have found is that every biological community has a minority of species that are behaving in unpredicted ways. Not...

Continue reading Plants and climate change: complexities and surprises (review)

Responses of beech and spruce foliage to elevated carbon dioxide, increased nitrogen deposition and soil type

Although enhanced carbon fixation by forest trees may contribute significantly to mitigating an increase in atmospheric CO2, capacities for this fixation vary greatly among different tree species and locations. In a study published in AoB PLANTS, Günthardt-Goerg and Vollenweider compared reactions in the foliage of a deciduous and a coniferous tree species (important central European trees, beech and spruce) to an elevated supply of CO2 and evaluated the importance of the soil type and increased nitrogen deposition on foliar nutrient concentrations and cellular stress reactions. Over four years young central European beech and spruce trees, growing on either acidic or...

Continue reading Responses of beech and spruce foliage to elevated carbon dioxide, increased nitrogen deposition and soil type

Leaf hydraulic conductance at elevated [CO2] and temperature

Leaf hydraulic conductance at elevated [CO2] and temperature

Leaf hydraulic properties are strongly linked with transpiration and photosynthesis in many species, but it is not known if gas exchange and hydraulics will have co-ordinated responses to climate change. Locke et al. study soybean (Glycine max) and find that leaf hydraulic conductance (Kleaf) does not change for plants grown at elevated [CO2] or elevated temperature, despite changes in photosynthesis and stomatal conductance. This lack of coordination between Kleaf and gas exchange in response to growth environment is observed in both field- and chamber-grown soybeans. Such an imbalance could lead to hydraulic limitation of photosynthesis under extreme environmental conditions.

Continue reading Leaf hydraulic conductance at elevated [CO2] and temperature


Nitrogen and water use efficiencies under elevated CO2

Nitrogen and water use efficiencies under elevated CO2

Water and nitrogen are two limiting resources for biomass production of terrestrial vegetation. Palmroth et al. employ optimization theory to quantify interactions between marginal water and nitrogen resource use efficiencies of Pinus taeda needles grown under elevated atmospheric CO2 concentration and soil nitrogen amendments in a free-air CO2 enrichment (FACE) experiment. They show that when foliar nitrogen content varies on time scales much longer than stomatal conductance, marginal nitrogen use efficiency is complementary to the square-root of marginal water use efficiency. The novel analytical expression can be employed not only to scale-up carbon and water fluxes from leaf to ecosystem, but...

Continue reading Nitrogen and water use efficiencies under elevated CO2