Balancing trade-offs: Enhanced carbon assimilation and productivity with reduced nutritional value in a well-watered C pasture under a warmer CO-enriched atmosphere.

The concentration of atmospheric CO and temperature are pivotal components of ecosystem productivity, carbon balance, and food security. In this study, we investigated the impacts of a warmer climate (+2 °C above ambient temperature) and an atmosphere enriched with CO (600 ppm) on gas exchange, antioxidant enzymatic system, growth, nutritive value, and digestibility of a well-watered, managed pasture of Megathyrsus maximus, a tropical C forage grass, under field conditions. Elevated [CO] (eC) improved photosynthesis and reduced stomatal conductance, resulting in increased water use efficiency and plant C content.

Silicon mitigates the negative impacts of salt stress in soybean plants.

Background: Soybean is widely cultivated around the world, including regions with salinity conditions. Salt stress impairs plant physiology and growth, but recent evidence suggests that silicon (Si) is able to mitigate this stressful condition. Therefore, the purpose of this study was to evaluate how different strategies of Si application impact on salt stress tolerance of an intermediate Si accumulator species (soybean).

Warming offsets the benefits of elevated CO in water relations while amplifies elevated CO-induced reduction in forage nutritional value in the C grass .

Tropical grasslands are very important to global carbon and water cycles. C plants have increased heat tolerance and a CO concentrating mechanism that often reduces responses to elevated concentrations of CO ([CO]). Despite the importance of tropical grasslands, there is a scarcity of studies that elucidate how managed tropical grasslands will be affected by elevated [CO] and warming.

Adjustments in photosynthetic pigments, PS II photochemistry and photoprotection in a tropical C4 forage plant exposed to warming and elevated [CO].

Global climate change will impact crops and grasslands, affecting growth and yield. However, is not clear how the combination of warming and increased atmospheric carbon dioxide concentrations ([CO]) will affect the photosystem II (PSII) photochemistry and the photosynthetic tissue photoinhibition and photoprotection on tropical forages. Here, we evaluated the effects of elevated [CO] (∼600 μmol mol) and warming (+2 °C increase temperature) on the photochemistry of photosystem II and the photoprotection strategies of a tropical C4 forage Panicum maximum Jacq.

Future warming will change the chemical composition and leaf blade structure of tropical C and C forage species depending on soil moisture levels.

Temperature and soil moisture strongly affect the nutritional value and digestibility of forage plants through changes in leaf chemical composition or the proportion of leaf blade tissues. In this study, we aimed to evaluate leaf blade anatomical modifications of two tropical forage species, Stylosanthes capitata (C) and Megathyrsus maximus (C) under warmed conditions (+2 °C) at well-watered and rainfed conditions and investigate the interactions between leaf anatomical alterations, leaf chemical composition, and leaf digestibility. Experiments were conducted under field conditions using a Temperature-free air-controlled enhancement (T-FACE) system.

Challenges of Biomass Utilization for Bioenergy in a Climate Change Scenario.

The climate changes expected for the next decades will expose plants to increasing occurrences of combined abiotic stresses, including drought, higher temperatures, and elevated CO atmospheric concentrations. These abiotic stresses have significant consequences on photosynthesis and other plants' physiological processes and can lead to tolerance mechanisms that impact metabolism dynamics and limit plant productivity. Furthermore, due to the high carbohydrate content on the cell wall, plants represent a an essential source of lignocellulosic biomass for biofuels production.

Are the interaction effects of warming and drought on nutritional status and biomass production in a tropical forage legume greater than their individual effects?

Drought alone and drought plus warming will change the nutrient requirements and biomass distributions of Stylosanthes capitata, while warming will be advantageous only under well-watered condition for the next decades. Climate change effects on natural and managed ecosystems are difficult to predict due to its multi-factor nature. However, most studies that investigate the impacts of climate change factors on plants, such as warming or drought, were conducted under one single stress and controlled environments.

How does leaf physiological acclimation impact forage production and quality of a warmed managed pasture of Stylosanthes capitata under different conditions of soil water availability?

Tropical pastures play a significant role in the global carbon cycle and are crucial for world livestock production. Despite its importance, there is a paucity of field studies that clarify how tropical pasture species will be affected by environmental changes predicted for tropical regions. Using a temperature-free air-controlled enhancement (T-FACE) system, we increased canopy temperature (+2 °C over ambient) and evaluated the effects of warming under two soil moisture conditions in a factorial design over the physiology, forage production, and forage quality of a tropical forage legume, Stylosanthes capitata.

Changes in soil water availability and air-temperature impact biomass allocation and C:N:P stoichiometry in different organs of Stylosanthes capitata Vogel.

Temperature and soil water availability play important roles in the biogeochemical cycles of essential elements for plant growth, such as carbon (C), nitrogen (N), and phosphorus (P). In this study, we investigated how drought and warming impact C:N:P stoichiometric ratios of different plant organs (leaves, inflorescences, and stems), and biomass allocation and production of a field-grown pasture of Stylosanthes capitata, a tropical forage legume. We evaluated the effects of elevated temperature (+2 °C above ambient temperature) under two conditions of soil water availability, irrigated, and non-irrigated.

Correction: Increasing atmospheric CO2 and canopy temperature induces anatomical and physiological changes in leaves of the C4 forage species Panicum maximum.

[This corrects the article DOI: 10.1371/journal.pone.

Elevated CO2 and warming change the nutrient status and use efficiency of Panicum maximum Jacq.

Panicum maximum Jacq. 'Mombaça' (Guinea grass) is a C4 forage grass widely used in tropical pastures for cattle feeding. In this study, we evaluated the isolated and combined effects of warming and elevated CO2 concentration [CO2] during summer on nutrient content, nutrient accumulation, nutrient use efficiency and growth of P.

Stomatal Development and Conductance of a Tropical Forage Legume Are Regulated by Elevated [CO] Under Moderate Warming.

The opening and closing of stomata are controlled by the integration of environmental and endogenous signals. Here, we show the effects of combining elevated atmospheric carbon dioxide concentration ( ; 600 μmol mol) and warming (+2°C) on stomatal properties and their consequence to plant function in a Vogel (C) tropical pasture. The treatment alone reduced stomatal density, stomatal index, and stomatal conductance ( ), resulting in reduced transpiration, increased leaf temperature, and leading to maintenance of soil moisture during the growing season.

Short-term warming and water stress affect Panicum maximum Jacq. stoichiometric homeostasis and biomass production.

Climate changes affect the growth of forage species. However, information regarding the effects of global climate change on the stoichiometry of tropical pastures is lacking, especially under field conditions. Such information is crucial to understand how temperature conditions and water availability states are likely to affect the stoichiometric homeostasis and biomass production of Panicum maximum, an important C4 tropical forage species, under future climate change scenarios.

Increasing atmospheric CO2 and canopy temperature induces anatomical and physiological changes in leaves of the C4 forage species Panicum maximum.

Changes in leaf anatomy and ultrastructure are associated with physiological performance in the context of plant adaptations to climate change. In this study, we investigated the isolated and combined effects of elevated atmospheric CO2 concentration ([CO2]) up to 600 μmol mol-1 (eC) and elevated temperature (eT) to 2°C more than the ambient canopy temperature on the ultrastructure, leaf anatomy, and physiology of Panicum maximum Jacq. grown under field conditions using combined free-air carbon dioxide enrichment (FACE) and temperature free-air controlled enhancement (T-FACE) systems.

Warming and water deficit impact leaf photosynthesis and decrease forage quality and digestibility of a C4 tropical grass.

Global warming is predicted to cause more intense extreme events such as heat waves, flooding and severe droughts, producing significant effects on agriculture. In tropics, climate change will severely impact livestock production affecting water availability, forage quality and food for cattle. We investigated the isolated and combined effects of soil water deficit (wS) and + 2°C increase in canopy temperature (eT) on leaf gas exchange, chlorophyll fluorescence, carbohydrate content, forage quality and in vitro dry matter digestibility (IVDMD) of a field-grown C4 tropical forage grass Panicum maximum Jacq.