scholarly journals Leaf gas exchange in cowpea and CO2 efflux in soil irrigated with saline water

2017 ◽  
Vol 21 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Wanderson J. de Oliveira ◽  
Edivan R. de Souza ◽  
Jailson C. Cunha ◽  
Ênio F. de F. e Silva ◽  
Venâncio de L. Veloso
Keyword(s):  
Soil Respiration ◽  
Water Use Efficiency ◽  
Water Use ◽  
Saline Water ◽  
Leaf Gas Exchange ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

ABSTRACT Leaf gas exchanges in plants and soil respiration are important tools for assessing the effects of salinity on the soil-plant system. An experiment was conducted with cowpea irrigated with saline water (0, 2.5, 5.0, 7.5, 10.0 and 12.5 dS m-1) prepared with two sources: NaCl and a mixture of Ca, Mg, Na, K and Cl ions in a randomized block design and a 6 x 2 factorial scheme, with four replicates, totaling 48 experimental plots. At 20 days after planting (DAP), plants were evaluated for net photosynthesis (A), stomatal conductance (gs) and transpiration (E) using the Infra-Red Gas Analyzer (Model XT6400- LICOR), and water use efficiency, intrinsic water use efficiency and instantaneous efficiency of carboxylation were calculated. At 60 DAP, the soil CO2 efflux (soil respiration) was determined with a camera (Model 6400-09- LICOR). Salinity caused reductions in A, gs and E. However, the salt source did not have significant effect on these variables. Soil CO2 efflux was reduced with the increase in the electrical conductivity, especially in the mixture of ions.

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 Coordination of stomata and vein patterns with leaf width underpins water use efficiency in a C4 crop

2021 ◽  
Author(s):  
Ling Pan ◽  
Barbara George-Jaeggli ◽  
Andrew Borrell ◽  
David Jordan ◽  
Fiona Koller ◽  
...  
Keyword(s):  
Energy Balance ◽  
Water Use Efficiency ◽  
Water Use ◽  
Stomatal Density ◽  
Leaf Gas Exchange ◽  
Crop Productivity ◽  
Stomatal Aperture ◽  
Leaf Width ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Despite its importance for crop productivity in drought-affected environments, the underlying mechanisms of variation in intrinsic water use efficiency (iWUE) are not well understood, especially in C4 plants. Recently, Cano et al. (2019) discovered that leaf width (LW) correlated negatively with iWUE and positively with stomatal conductance for water vapour (gsw) across several C4 grasses. Here, we analysed these relationships within 48 field-grown genotypes that cover a broad range of variation in LW in Sorghum bicolor, a well-adapted C4 crop to xeric and hot conditions, by measuring and modelling leaf gas exchange and leaf energy balance three times a day, using anatomical traits as potential drivers for iWUE. LW correlated negatively with iWUE and stomatal density, but positively with gsw, interveinal distance of longitudinal veins (IVDL) and the percentage of stomatal aperture relative to maximum. Energy balance modelling showed that wider leaves opened the stomata more to generate a more negative leaf-to-air temperature difference especially at midday, when air temperatures exceeded 40ºC. These results highlight the important role that LW plays in shaping iWUE through modification of vein and stomatal traits and by regulating stomatal aperture. Therefore, LW could be used as a predictor for higher iWUE among sorghum genotypes.

Increasing intrinsic water-use efficiency over the past 160 years does not stimulate tree growth in southeastern China

2018 ◽  
Vol 76 (2) ◽  
pp. 115-130 ◽  
Author(s):  
G Guo ◽  
K Fang ◽  
J Li ◽  
HW Linderholm ◽  
D Li ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Tree Growth ◽  
Southeastern China ◽  
The Past ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Improving Intrinsic Water-Use Efficiency and Crop Yield

Crop Science ◽  
2002 ◽  
Vol 42 (1) ◽  
pp. 122 ◽  
Author(s):  
A. G. Condon ◽  
R. A. Richards ◽  
G. J. Rebetzke ◽  
G. D. Farquhar
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Crop Yield ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

scholarly journals Impact of oxygation on soil respiration, yield and water use efficiency of three crop species

2010 ◽  
Vol 4 (4) ◽  
pp. 236-248 ◽  
Author(s):  
X. Chen ◽  
J. Dhungel ◽  
S. P. Bhattarai ◽  
M. Torabi ◽  
L. Pendergast ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Water Use Efficiency ◽  
Water Use ◽  
Crop Species ◽  
Use Efficiency

scholarly journals Significance of soil respiration from biological activity in the degradation processes of different types of organic matter

2020 ◽  
Vol 1 (2) ◽  
pp. 171-179
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Temperature Sensitivity ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Total Soil

Soil respiration is a major component of global carbon cycle. Therefore, it is crucial to understand the environmental controls on soil respiration for evaluating potential response of ecosystems to climate change. In a temperate deciduous forest (located in Northern-Hungary) we added or removed aboveground and belowground litter to determine total soil respiration. We investigated the relationship between total soil CO2 efflux, soil moisture, and soil temperature. Soil CO2 efflux was measured at each plot using soda-lime method. Temperature sensitivity of soil respiration (Q10) was monitored via measuring soil temperature on an hourly basis, while soil moisture was determined monthly. Soil respiration increased in control plots from the second year after implementing the treatment, but results showed fluctuations from one year to another. The effect of doubled litter was less significant than the effect of removal. Removed litter and root inputs caused substantial decrease in soil respiration. We found that temperature was more influential in the control of soil respiration than soil moisture. In plots with no litter Q10 varied in the largest interval. For treatment with doubled litter layer, temperature sensitivity of CO2 efflux did not change considerably. The effect of increasing soil temperature is more conspicuous to soil respiration in litter removal treatments since lack of litter causes greater irradiation. When exclusively leaf litter was considered, the effect of temperature on soil respiration was lower in treatments with added litter than with removed litter. Our results reveal that soil life is impacted by the absence of organic matter, rather than by an excess of organic matter. Results of CO2 emission from soils with different organic matter content can contribute to sustainable land use, considering the changed climatic factors caused by global climate change.

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