Disentangling the effects of atmospheric CO2 and climate on intrinsic water-use efficiency in South Asian tropical moist forest trees

2020 ◽  
Vol 40 (7) ◽  
pp. 904-916
Author(s):  
Mizanur Rahman ◽  
Mahmuda Islam ◽  
Aster Gebrekirstos ◽  
Achim Bräuning
Keyword(s):  
South Asian ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Annual Variability ◽  
Intrinsic Water Use Efficiency ◽  
Moist Forest ◽  
Increasing Trend ◽  
Use Efficiency ◽  
Species Specific

Abstract Due to the increase in atmospheric CO2 concentrations, the ratio of carbon fixed by assimilation to water lost by transpiration through stomatal conductance (intrinsic water-use efficiency, iWUE) shows a long-term increasing trend globally. However, the drivers of short-term (inter-annual) variability in iWUE of tropical trees are poorly understood. We studied the inter-annual variability in iWUE of three South Asian tropical moist forest tree species (Chukrasia tabularis A.Juss., Toona ciliata M. Roem. and Lagerstroemia speciosa L.) derived from tree-ring stable carbon isotope ratio (δ13C) in response to variations of environmental conditions. We found a significantly decreasing trend in carbon discrimination (Δ13C) and an increasing trend in iWUE in all the three species, with a species-specific long-term trend in intercellular CO2 concentration (Ci). Growing season temperatures were the main driver of inter-annual variability of iWUE in C. tabularis and L. speciosa, whereas previous year temperatures determined the iWUE variability in T. ciliata. Vapor pressure deficit was linked with iWUE only in C. tabularis. Differences in shade tolerance, tree stature and canopy position might have caused this species-specific variation in iWUE response to climate. Linear mixed effect modeling successfully simulated iWUE variability, explaining 41–51% of the total variance varying with species. Commonality analysis revealed that temperatures had a dominant influence on the inter-annual iWUE variability (64–77%) over precipitation (7–22%) and atmospheric CO2 concentration (3–6%). However, the long-term variations in iWUE were explicitly determined by the atmospheric CO2 increase (83–94%). Our results suggest that the elevated CO2 and concomitant global warming might have detrimental effects on gas exchange and other physiological processes in South Asian tropical moist forest trees.

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

scholarly journals Improved estimate of global gross primary production for reproducing its long-term variation, 1982–2017

2020 ◽  
Vol 12 (4) ◽  
pp. 2725-2746
Author(s):  
Yi Zheng ◽  
Ruoque Shen ◽  
Yawen Wang ◽  
Xiangqian Li ◽  
Shuguang Liu ◽  
...  
Keyword(s):  
Primary Production ◽  
Environmental Variables ◽  
Gross Primary Production ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Interannual Variations ◽  
Light Use Efficiency ◽  
Long Term Changes ◽  
Use Efficiency

Abstract. Satellite-based models have been widely used to simulate vegetation gross primary production (GPP) at the site, regional, or global scales in recent years. However, accurately reproducing the interannual variations in GPP remains a major challenge, and the long-term changes in GPP remain highly uncertain. In this study, we generated a long-term global GPP dataset at 0.05∘ latitude by 0.05∘ longitude and 8 d interval by revising a light use efficiency model (i.e., EC-LUE model). In the revised EC-LUE model, we integrated the regulations of several major environmental variables: atmospheric CO2 concentration, radiation components, and atmospheric vapor pressure deficit (VPD). These environmental variables showed substantial long-term changes, which could greatly impact the global vegetation productivity. Eddy covariance (EC) measurements at 95 towers from the FLUXNET2015 dataset, covering nine major ecosystem types around the globe, were used to calibrate and validate the model. In general, the revised EC-LUE model could effectively reproduce the spatial, seasonal, and annual variations in the tower-estimated GPP at most sites. The revised EC-LUE model could explain 71 % of the spatial variations in annual GPP over 95 sites. At more than 95 % of the sites, the correlation coefficients (R2) of seasonal changes between tower-estimated and model-simulated GPP are larger than 0.5. Particularly, the revised EC-LUE model improved the model performance in reproducing the interannual variations in GPP, and the averaged R2 between annual mean tower-estimated and model-simulated GPP is 0.44 over all 55 sites with observations longer than 5 years, which is significantly higher than those of the original EC-LUE model (R2=0.36) and other LUE models (R2 ranged from 0.06 to 0.30 with an average value of 0.16). At the global scale, GPP derived from light use efficiency models, machine learning models, and process-based biophysical models shows substantial differences in magnitude and interannual variations. The revised EC-LUE model quantified the mean global GPP from 1982 to 2017 as 106.2±2.9 Pg C yr−1 with the trend 0.15 Pg C yr−1. Sensitivity analysis indicated that GPP simulated by the revised EC-LUE model was sensitive to atmospheric CO2 concentration, VPD, and radiation. Over the period of 1982–2017, the CO2 fertilization effect on the global GPP (0.22±0.07 Pg C yr−1) could be partly offset by increased VPD (-0.17±0.06 Pg C yr−1). The long-term changes in the environmental variables could be well reflected in global GPP. Overall, the revised EC-LUE model is able to provide a reliable long-term estimate of global GPP. The GPP dataset is available at https://doi.org/10.6084/m9.figshare.8942336.v3 (Zheng et al., 2019).

Long-term relationships among atmospheric CO2 , stomata, and intrinsic water use efficiency in individual trees

2009 ◽  
Vol 96 (10) ◽  
pp. 1779-1786 ◽  
Author(s):  
Abraham J. Miller-Rushing ◽  
Richard B. Primack ◽  
Pamela H. Templer ◽  
Sarah Rathbone ◽  
Sharda Mukunda
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Atmospheric Co2 ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Individual Trees

scholarly journals Drought-induced mortality selectively affects Scots pine trees that show limited intrinsic water-use efficiency responsiveness to raising atmospheric CO2

2014 ◽  
Vol 41 (3) ◽  
pp. 244 ◽  
Author(s):  
Ana-Maria Hereş ◽  
Jordi Voltas ◽  
Bernat Claramunt López ◽  
Jordi Martínez-Vilalta
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Tree Mortality ◽  
Intercellular Co2 Concentration ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Growth Enhancement ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
The Impact

Widespread drought-induced tree mortality has been documented around the world, and could increase in frequency and intensity under warmer and drier conditions. Ecophysiological differences between dying and surviving trees might underlie predispositions to mortality, but are poorly documented. Here we report a study of Scots pines (Pinus sylvestris L.) from two sites located in north-eastern Iberian Peninsula where drought-associated mortality episodes were registered during the last few decades. Time trends of discrimination against 13C (Δ13C) and intrinsic water-use efficiency (WUEi) in tree rings at an annual resolution and for a 34 year period were used to compare co-occurring now-dead and surviving pines. Results indicate that both surviving and now-dead pines significantly increased their WUEi over time, although this increase was significantly lower for now-dead individuals. These differential WUEi trends corresponded to different scenarios describing how plant gas exchange responds to increasing atmospheric CO2 (Ca): the estimated intercellular CO2 concentration was nearly constant in surviving pines but tended to increase proportionally to Ca in now-dead trees. Concurrently, the WUEi increase was not paralleled by a growth enhancement, regardless of tree state, suggesting that in water-limited areas like the Mediterranean, it cannot overcome the impact of an increasingly warmer and drier climate on tree growth.

scholarly journals Impacts of Global Warming on the Radial Growth and Long-Term Intrinsic Water-Use Efficiency (iWUE) of Schrenk Spruce (Picea schrenkiana Fisch. et Mey) in the Sayram Lake Basin, Northwest China

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 380
Author(s):  
Li Qin ◽  
Yujiang Yuan ◽  
Huaming Shang ◽  
Shulong Yu ◽  
Weiping Liu ◽  
...  
Keyword(s):  
Global Warming ◽  
Radial Growth ◽  
Atmospheric Co2 ◽  
Lake Basin ◽  
Picea Schrenkiana ◽  
Co2 Concentrations ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Atmospheric Co2 Concentrations

Global warming and the sharp rise in atmospheric CO2 concentrations have a profound impact on forest ecosystems. To better manage these changes, a comprehensive understanding of forest ecosystem responses to global change is essential. There is a lack of knowledge about the growth response of Schrenk spruce (Picea schrenkiana Fisch. et Mey)—an endemic tree species found in the arid Central Asian region—to climate change and rising atmospheric CO2 concentrations. In this study, core samples of Schrenk spruce were collected in the Sayram Lake Basin, Xinjiang. Tree-ring radial growth and long-term intrinsic water-use efficiency (iWUE) chronologies were established based on standard tree-ring width and stable carbon isotope methods. The relationships between atmospheric CO2 concentrations, climate, radial growth, and iWUE were analyzed. Our results indicate that the iWUE of trees in this region has continued to rise rapidly but that radial growth has not increased over the past 160 years. The main factor affecting iWUE is atmospheric CO2 concentrations (Ca), whereas the radial growth is much more sensitive to water availability. This may explain why the increase Ca has not had a fertilizer effect on the radial growth of trees.

Stomatal and non-stomatal limitations of photosynthesis under water stress in field-grown grapevines

1999 ◽  
Vol 26 (5) ◽  
pp. 421 ◽  
Author(s):  
J. M. Escalona ◽  
J. Flexas ◽  
H. Medrano
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Relative Increase ◽  
Apparent Quantum Yield ◽  
Intrinsic Water Use Efficiency ◽  
Regulation Mechanisms ◽  
Use Efficiency ◽  
Alternative Processes ◽  
Stomatal Limitations

Long-term induced water stress in field-grown grapevine leads to a progressive decline of stomatal conductance, accompanied by a decrease in CO 2 assimilation (40%). The apparent quantum yield also decreases (59%), which may reflect a relative increase in alternative processes for electron consumption. There is also a shift to non-stomatal regulation, as judged from significant depletions (37%) in maximum photosynthesis rate at saturating CO 2 related to limited ribulose biphosphate (RuBP) regeneration, whereas small, non-significant effects are observed on carboxylation efficiency. A high correlation (87%) between photosynthesis and stomatal conductance is observed for all experimental data and declines in intercellular CO 2 concentration parallel reductions in stomatal conductance. The data show that field response of grapevines to increasing soil water deficit involves stomatal and non-stomatal effects but, due to gradually induced drought, regulation mechanisms able to adjust mesophyll capacity to the average CO 2 supply. The non-stomatal adjustment seems to be exerted mainly in metabolic pathways related with the RuBP regeneration. Contrasting characteristics were observed for both cultivars. Tempranillo exploited the non-stressful conditions successfully, whereas Manto Negro, responding to its reputation as more drought resistant, showed a higher intrinsic water use efficiency, particularly for low water availability. This advantage seems to be due to lower non-stomatal limitations.

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