scholarly journals Missing Gaps in the Estimation of the Carbon Gains Service from Light Use Efficiency Models

2013 ◽  
pp. 125-144
Keyword(s):  
Light Use Efficiency ◽  
Use Efficiency

Enhanced light interception and light use efficiency explain overyielding in young tree communities

2021 ◽  
Author(s):  
Laura J. Williams ◽  
Ethan E. Butler ◽  
Jeannine Cavender‐Bares ◽  
Artur Stefanski ◽  
Karen E. Rice ◽  
...  
Keyword(s):  
Light Interception ◽  
Light Use Efficiency ◽  
Young Tree ◽  
Tree Communities ◽  
Use Efficiency

scholarly journals A common garden experiment examining light use efficiency and heat sum to explain growth differences in native and exotic Pinus taeda

2018 ◽  
Vol 425 ◽  
pp. 35-44 ◽  
Author(s):  
Timothy J. Albaugh ◽  
Thomas R. Fox ◽  
Chris A. Maier ◽  
Otávio C. Campoe ◽  
Rafael A. Rubilar ◽  
...  
Keyword(s):  
Pinus Taeda ◽  
Common Garden ◽  
Light Use Efficiency ◽  
Common Garden Experiment ◽  
Use Efficiency ◽  
Growth Differences

Biogeographical Patterns of Light Use efficiency?

2021 ◽  
Author(s):  
David Sandoval ◽  
Iain Colin Prentice
Keyword(s):  
Maximum Rate ◽  
Spatial Organization ◽  
Gross Primary Production ◽  
Incident Light ◽  
Direct Consequence ◽  
Theoretical Explanation ◽  
Light Use Efficiency ◽  
Mountain Regions ◽  
Use Efficiency ◽  
Photosynthetic Traits

<p>The emergent spatial organization of ecosystems in elevational gradients suggest that some ecosystem processes, important enough to shape morphological traits, must show similar patterns.</p><p>The most important of these processes, gross primary production (GPP), usually (albeit with some exceptions) decreases with elevation. This was previously thought to be a direct consequence either of the decrease in temperature, or the decrease of incident light due to cloud cover. However, some recent developments in photosynthetic theory, plus the unprecedented availability of ecophysiological data, support the hypothesis that plants acclimate (optimize) their photosynthetic traits to the environment. In this new theoretical context, the temperature is no longer considered as a major constraining factor, except when either freezing or excessively high temperatures inhibit plant function generally.</p><p>Two of the most important photosynthetic traits, the maximum rate of carboxylation (V<sub>CMAX</sub>) and the intrinsic quantum efficiency (φ<sub>o</sub>), vary in opposite directions with increasing elevation. Plants tend to increase V<sub>CMAX</sub> to compensate for a decrease in the ratio leaf-internal to ambient partial pressures of CO<sub>2</sub>, while φ<sub>o</sub> increases with temperature up to a plateau. To explore how these different responses, documented at leaf level, converge in emergent spatial patterns at ecosystem scale we considered how elevation shape light use efficiency (defined as the ratio of CO<sub>2</sub> assimilated over light absorbed) over mountain regions worldwide. We used data from eddy-covariance flux towers, from different networks, located in mountain regions around the world, adding up to 618 station-years of record. To complement our analysis, we included theoretical predictions using an optimality model (P-model) and evaluated changes in the spatial pattern with simulation experiments.</p><p>Empirically we found an asymptotic response of LUE to the average daytime temperature during the growing season with increasing elevation, and a small, but globally consistent effect of elevation on LUE. We propose a theoretical explanation for the observation that temperature differences have little impact on the biogeographical pattern of LUE, but we also find that different assumptions on the acclimation of the maximum rate of electron transport (J<sub>MAX</sub>) and φ<sub>o</sub> change this pattern.</p>

scholarly journals Protective Netting Improves Leaf-level Photosynthetic Light Use Efficiency in ‘Honeycrisp’ Apple Under Heat Stress

HortScience ◽  
2018 ◽  
Vol 53 (10) ◽  
pp. 1416-1422 ◽  
Author(s):  
Giverson Mupambi ◽  
Stefano Musacchi ◽  
Sara Serra ◽  
Lee A. Kalcsits ◽  
Desmond R. Layne ◽  
...  
Keyword(s):  
Heat Stress ◽  
Solar Radiation ◽  
Leaf Gas Exchange ◽  
Growing Season ◽  
High Light ◽  
Weather Data ◽  
Light Use Efficiency ◽  
Ambient Temperatures ◽  
Leaf Level ◽  
Use Efficiency

Globally, apple production often occurs in semiarid climates characterized by high summer temperatures and solar radiation. Heat stress events occur regularly during the growing season in these regions. For example, in the semiarid eastern half of Washington State, historic weather data show that, on average, 33% of the days during the growing season exceed 30 °C. To mediate some of the effects of heat stress, protective netting (PN) can be used to reduce the occurrence of fruit sunburn. However, the impacts of reduced solar radiation in a high light environment on light-use efficiency and photosynthesis are poorly understood. We sought to understand the ecophysiological response of apple (Malus domestica Borkh. cv. Honeycrisp) under blue photoselective PN during days with low (26.6 °C), moderate (33.7 °C), or high (38.1 °C) ambient temperatures. Two treatments were evaluated; an uncovered control and blue photoselective PN. Maximum photochemical efficiency of PSII, or photosystem II (Fv/Fm) was significantly greater at all measurement times under blue photoselective PN compared with the control on days with high ambient temperatures. Fv/Fm dropped below 0.79, which is considered the threshold for stress, at 1000 hr in the control and at 1200 hr under blue photoselective PN on a day with high ambient temperature. On days with low or moderate ambient temperatures, Fv/Fm was significantly greater under blue photoselective PN at 1400 hr, which coincided with the peak in solar radiation. ‘Honeycrisp’ apple exhibited dynamic photoinhibition as shown by the diurnal decline in Fv/Fm. Quantum photosynthetic yield of PSII (ΦPSII) was also generally greater under blue photoselective PN compared with the control for days with moderate or high ambient temperatures. Photochemical reflectance index (ΔPRI), the difference in reflectance between a stress-responsive and nonstress-responsive wavelength, was greater under PN compared with the control on the day with high ambient temperatures, with no differences observed under low or moderate ambient temperatures. Leaf gas exchange did not show noticeable improvement under blue photoselective netting when compared with the control despite the improvement in leaf-level photosynthetic light use efficiency. In conclusion, PN reduced incoming solar radiation, improved leaf-level photosynthetic light use efficiency, and reduced the symptoms of photoinhibition in a high-light, arid environment.

Determining ecosystem light use efficiency for carbon exchange from satellite

2005 ◽  
Author(s):  
K. Fred Huemmrich ◽  
Elizabeth M. Middleton ◽  
Guillaume Drolet ◽  
Forrest G. Hall ◽  
Hank Margolis ◽  
...  
Keyword(s):  
Light Use Efficiency ◽  
Carbon Exchange ◽  
Use Efficiency

scholarly journals Simulating Spatiotemporal Dynamics of Sichuan Grassland Net Primary Productivity Using the CASA Model and In Situ Observations

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Chuanjiang Tang ◽  
Xinyu Fu ◽  
Dong Jiang ◽  
Jingying Fu ◽  
Xinyue Zhang ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Alpine Meadow ◽  
Growth Period ◽  
Temporal Variations ◽  
Light Use Efficiency ◽  
Important Indicator ◽  
Casa Model ◽  
Use Efficiency

Net primary productivity (NPP) is an important indicator for grassland resource management and sustainable development. In this paper, the NPP of Sichuan grasslands was estimated by the Carnegie-Ames-Stanford Approach (CASA) model. The results were validated with in situ data. The overall precision reached 70%; alpine meadow had the highest precision at greater than 75%, among the three types of grasslands validated. The spatial and temporal variations of Sichuan grasslands were analyzed. The absorbed photosynthetic active radiation (APAR), light use efficiency (ε), and NPP of Sichuan grasslands peaked in August, which was a vigorous growth period during 2011. High values of APAR existed in the southwest regions in altitudes from 2000 m to 4000 m. Light use efficiency (ε) varied in the different types of grasslands. The Sichuan grassland NPP was mainly distributed in the region of 3000–5000 m altitude. The NPP of alpine meadow accounted for 50% of the total NPP of Sichuan grasslands.

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