Enhanced decreases in rice evapotranspiration in response to elevated atmospheric carbon dioxide under warmer environments.

A short period of exposure to elevated CO is known to decrease evapotranspiration via stomatal closure. Based on theoretical evaluation of a canopy transpiration model, we hypothesized that this decrease in the evapotranspiration of rice under elevated CO was greater under higher temperature conditions due to an increased sensitivity of transpiration to changes in CO induced by the greater vapour pressure deficit. In a temperature gradient chamber-based experiment, a 200 ppm increase in CO concentration led to 0.

Carbon uptake in Eurasian boreal forests dominates the high-latitude net ecosystem carbon budget.

Arctic-boreal landscapes are experiencing profound warming, along with changes in ecosystem moisture status and disturbance from fire. This region is of global importance in terms of carbon feedbacks to climate, yet the sign (sink or source) and magnitude of the Arctic-boreal carbon budget within recent years remains highly uncertain. Here, we provide new estimates of recent (2003-2015) vegetation gross primary productivity (GPP), ecosystem respiration (R ), net ecosystem CO exchange (NEE; R  - GPP), and terrestrial methane (CH ) emissions for the Arctic-boreal zone using a satellite data-driven process-model for northern ecosystems (TCFM-Arctic), calibrated and evaluated using measurements from >60 tower eddy covariance (EC) sites.

The three major axes of terrestrial ecosystem function.

The leaf economics spectrum and the global spectrum of plant forms and functions revealed fundamental axes of variation in plant traits, which represent different ecological strategies that are shaped by the evolutionary development of plant species. Ecosystem functions depend on environmental conditions and the traits of species that comprise the ecological communities. However, the axes of variation of ecosystem functions are largely unknown, which limits our understanding of how ecosystems respond as a whole to anthropogenic drivers, climate and environmental variability.

Temperature thresholds of ecosystem respiration at a global scale.

Ecosystem respiration is a major component of the global terrestrial carbon cycle and is strongly influenced by temperature. The global extent of the temperature-ecosystem respiration relationship, however, has not been fully explored. Here, we test linear and threshold models of ecosystem respiration across 210 globally distributed eddy covariance sites over an extensive temperature range.

A high-performance system of multiple gas-exchange chambers with a laser spectrometer to estimate leaf photosynthesis, stomatal conductance, and mesophyll conductance.

Direct measurements of ecophysiological processes such as leaf photosynthesis are often hampered due to the excessive time required for gas-exchange measurements and the limited availability of multiple gas analyzers. Although recent advancements in commercially available instruments have improved the ability to take measurements more conveniently, the amount of time required for each plant sample to acclimate to chamber conditions has not been sufficiently reduced. Here we describe a system of multiple gas-exchange chambers coupled with a laser spectrometer that employs tunable diode laser absorption spectroscopy (TDLAS) to measure leaf photosynthesis, stomatal conductance, and mesophyll conductance.

A High-Yielding Rice Cultivar "Takanari" Shows No N Constraints on CO Fertilization.

Enhancing crop yield response to elevated CO concentrations (E-[CO]) is an important adaptation measure to climate change. A high-yielding indica rice cultivar "Takanari" has recently been identified as a potential candidate for high productivity in E-[CO] resulting from its large sink and source capacities. To fully utilize these traits, nitrogen should play a major role, but it is unknown how N levels influence the yield response of Takanari to E-[CO].

Increasing canopy photosynthesis in rice can be achieved without a large increase in water use-A model based on free-air CO enrichment.

Achieving higher canopy photosynthesis rates is one of the keys to increasing future crop production; however, this typically requires additional water inputs because of increased water loss through the stomata. Lowland rice canopies presently consume a large amount of water, and any further increase in water usage may significantly impact local water resources. This situation is further complicated by changing the environmental conditions such as rising atmospheric CO concentration ([CO ]).

Light-stress avoidance mechanisms in a Sphagnum-dominated wet coastal Arctic tundra ecosystem in Alaska.

The Arctic experiences a high-radiation environment in the summer with 24-hour daylight for more than two months. Damage to plants and ecosystem metabolism can be muted by overcast conditions common in much of the Arctic. However, with climate change, extreme dry years and clearer skies could lead to the risk of increased photoxidation and photoinhibition in Arctic primary producers.