scholarly journals Elevated CO<sub>2</sub>, increased leaf-level productivity, and water-use efficiency during the early Miocene

2020 ◽  
Vol 16 (4) ◽  
pp. 1509-1521
Author(s):  
Tammo Reichgelt ◽  
William J. D'Andrea ◽  
Ailín del C. Valdivia-McCarthy ◽  
Bethany R. S. Fox ◽  
Jennifer M. Bannister ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Leaf Gas Exchange ◽  
Atmospheric Co2 ◽  
Early Miocene ◽  
Intrinsic Water Use Efficiency ◽  
Leaf Level ◽  
Fertilization Effect ◽  
Use Efficiency

Abstract. Rising atmospheric CO2 is expected to increase global temperatures, plant water-use efficiency, and carbon storage in the terrestrial biosphere. A CO2 fertilization effect on terrestrial vegetation is predicted to cause global greening as the potential ecospace for forests expands. However, leaf-level fertilization effects, such as increased productivity and water-use efficiency, have not been documented from fossil leaves in periods of heightened atmospheric CO2. Here, we use leaf gas-exchange modeling on a well-preserved fossil flora from early Miocene New Zealand, as well as two previously published tropical floras from the same time period, to reconstruct atmospheric CO2, leaf-level productivity, and intrinsic water-use efficiency. Leaf gas-exchange rates reconstructed from early Miocene fossils, which grew at southern temperate and tropical latitudes when global average temperatures were 5–6 ∘C higher than today, reveal that atmospheric CO2 was ∼450–550 ppm. Early Miocene CO2 was similar to projected values for 2040 CE and is consistent with an Earth system sensitivity of 3–7 ∘C to a doubling of CO2. The Southern Hemisphere temperate leaves had higher reconstructed productivity than modern analogs, likely due to a longer growing season. This higher productivity was presumably mirrored at northern temperate latitudes as well, where a greater availability of landmass would have led to increased carbon storage in forest biomass relative to today. Intrinsic water-use efficiency of both temperate and tropical forest trees was high, toward the upper limit of the range for modern trees, which likely expanded the habitable range in regions that could not support forests with high moisture demands under lower atmospheric CO2. Overall, early Miocene elevated atmospheric CO2 sustained globally higher temperatures, and our results provide the first empirical evidence of concomitant enhanced intrinsic water-use efficiency, indicating a forest fertilization effect.

scholarly journals Elevated CO<sub>2</sub>, increased leaf-level productivity and water-use efficiency during the early Miocene

2020 ◽  
Author(s):  
Tammo Reichgelt ◽  
William J. D'Andrea ◽  
Ailín del C. Valdivia-McCarthy ◽  
Bethany R.S. Fox ◽  
Jennifer M. Bannister ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Carbon Storage ◽  
Water Use ◽  
Leaf Gas Exchange ◽  
Atmospheric Co2 ◽  
Early Miocene ◽  
Intrinsic Water Use Efficiency ◽  
Leaf Level ◽  
Fertilization Effect ◽  
Use Efficiency

Abstract. Rising atmospheric CO2 is expected to increase global temperatures, plant water-use efficiency, and carbon storage in the terrestrial biosphere. A CO2 fertilization effect on terrestrial vegetation is predicted to cause global greening as the potential ecospace for forests expands. However, leaf-level fertilization effects, such as increased productivity and water-use efficiency, have not been documented from fossil leaves in periods of heightened atmospheric CO2. Leaf gas-exchange rates reconstructed from early Miocene fossils which grew at southern temperate and tropical latitudes, when global average temperatures were 5–6 °C higher than today reveal that atmospheric CO2 was ~ 450–550 ppm. Early Miocene CO2 is similar to projected values for 2040AD, and consistent with Earth System Sensitivity of 3–7 °C to a doubling of CO2. While early Miocene leaves had photosynthetic rates similar to modern plants, southern temperate leaves were more productive than modern due to a longer growing season. This higher productivity was likely mirrored at northern temperate latitudes as well, where a greater availability of landmass would have led to increased carbon storage in forest biomass relative to today. Intrinsic water-use efficiency of both temperate and tropical forest trees was high, toward the upper limit of the range for modern trees, which likely expanded the habitable range in regions that could not support forests with high moisture demands under lower atmospheric CO2. Overall, early Miocene elevated atmospheric CO2 sustained globally higher temperatures and our results reveal the first empirical evidence of concomitant enhanced intrinsic water-use efficiency, indicating a forest fertilization effect.

scholarly journals Water Deficit Modulates the CO2 Fertilization Effect on Plant Gas Exchange and Leaf-Level Water Use Efficiency: A Meta-Analysis

2021 ◽  
Vol 12 ◽  
Author(s):  
Fei Li ◽  
Dagang Guo ◽  
Xiaodong Gao ◽  
Xining Zhao
Keyword(s):  
Gas Exchange ◽  
Water Use Efficiency ◽  
Soil Water ◽  
Water Deficit ◽  
Water Use ◽  
Future Climate Change ◽  
Leaf Level ◽  
Fertilization Effect ◽  
Use Efficiency ◽  
Stimulation Of

Elevated atmospheric CO2 concentrations ([eCO2]) and soil water deficits significantly influence gas exchange in plant leaves, affecting the carbon-water cycle in terrestrial ecosystems. However, it remains unclear how the soil water deficit modulates the plant CO2 fertilization effect, especially for gas exchange and leaf-level water use efficiency (WUE). Here, we synthesized a comprehensive dataset including 554 observations from 54 individual studies and quantified the responses for leaf gas exchange induced by e[CO2] under water deficit. Moreover, we investigated the contribution of plant net photosynthesis rate (Pn) and transpiration rates (Tr) toward WUE in water deficit conditions and e[CO2] using graphical vector analysis (GVA). In summary, e[CO2] significantly increased Pn and WUE by 11.9 and 29.3% under well-watered conditions, respectively, whereas the interaction of water deficit and e[CO2] slightly decreased Pn by 8.3%. Plants grown under light in an open environment were stimulated to a greater degree compared with plants grown under a lamp in a closed environment. Meanwhile, water deficit reduced Pn by 40.5 and 37.8%, while increasing WUE by 24.5 and 21.5% under ambient CO2 concentration (a[CO2]) and e[CO2], respectively. The e[CO2]-induced stimulation of WUE was attributed to the common effect of Pn and Tr, whereas a water deficit induced increase in WUE was linked to the decrease in Tr. These results suggested that water deficit lowered the stimulation of e[CO2] induced in plants. Therefore, fumigation conditions that closely mimic field conditions and multi-factorial experiments such as water availability are needed to predict the response of plants to future climate change.

Diurnal Time Course of Leaf Gas Exchange Rates and Related Characters in Drought-Acclimated and Irrigated Trifolium Subterraneum.

1995 ◽  
Vol 22 (3) ◽  
pp. 461 ◽  
Author(s):  
J Vadell ◽  
C Cabot ◽  
H Medrano
Keyword(s):  
Gas Exchange ◽  
Exchange Rates ◽  
Water Use Efficiency ◽  
Water Use ◽  
Leaf Gas Exchange ◽  
Trifolium Subterraneum ◽  
Co2 Assimilation ◽  
Carbon Gain ◽  
Assimilation Rate ◽  
Use Efficiency

The effects of drought acclimation on the diurnal time courses of photosynthesis and related characters were studied in Trifolium subterraneum L. leaves during two consecutive late spring days. Leaf CO2 assimilation rate and transpiration rate followed irradiance variations in irrigated plants. Under drought, a bimodal pattern of leaf CO2 assimilation rate developed although stomatal conductance remained uniform and low. Instantaneous water-use efficiency was much higher in droughted plants during the early morning and late evening, while during the middle of the day it was close to the value of irrigated plants. Net carbon gain in plants under drought reached 40% of the carbon gain in irrigated plants with a significant saving of water (80%). Average data derived from midday values of leaf CO2 assimilation rates and instantaneous water-use efficiency did not provide good estimates of the daily carbon gain and water-use efficiency for droughted leaves. Coupled with the morphological changes as a result of acclimation to progressive drought, modifications of diurnal patterns of leaf gas exchange rates effectively contribute to a sustained carbon gain during drought. These modifications significantly improve water-use efficiency, mainly by enabling the plant to take advantage of morning and evening hours with high air humidity.

The effect of long-term atmospheric CO2 enrichment on the intrinsic water-use efficiency of sour orange trees

Chemosphere ◽  
2003 ◽  
Vol 50 (2) ◽  
pp. 217-222 ◽  
Author(s):  
S.W. Leavitt ◽  
S.B. Idso ◽  
B.A. Kimball ◽  
J.M. Burns ◽  
A. Sinha ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Co2 Enrichment ◽  
Atmospheric Co2 ◽  
Sour Orange ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Orange Trees

The effect of strobilurins on leaf gas exchange, water use efficiency and ABA content in grapevine under field conditions

2012 ◽  
Vol 169 (4) ◽  
pp. 379-386 ◽  
Author(s):  
Antonio Diaz-Espejo ◽  
María Victoria Cuevas ◽  
Miquel Ribas-Carbo ◽  
Jaume Flexas ◽  
Sebastian Martorell ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Leaf Gas Exchange ◽  
Field Conditions ◽  
Use Efficiency ◽  
Aba Content

scholarly journals Supplementary material to "Elevated CO<sub>2</sub>, increased leaf-level productivity and water-use efficiency during the early Miocene"

2020 ◽  
Author(s):  
Tammo Reichgelt ◽  
William J. D'Andrea ◽  
Ailín del C. Valdivia-McCarthy ◽  
Bethany R.S. Fox ◽  
Jennifer M. Bannister ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Early Miocene ◽  
Leaf Level ◽  
Use Efficiency ◽  
Supplementary Material
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