Effect of Increased Atmospheric CO2 Concentration on Water-Use Efficiency of Plants

(1) Background: Elevated atmospheric CO2 concentration affects the growth and development of the rice crop. In Southern Brazil, rice is traditionally produced with continuous irrigation, implying a significant amount of water used. Besides, continuous flooding favors the uptake of toxic elements such as arsenic (As) and cadmium (Cd). In this work, one Brazilian rice cultivar (IRGA 424) was tested for the effects of elevated CO2 concentration and different water regimes on rice yield, and As and Cd accumulation in grain. (2) Methods: Rice was grown in two CO2 concentrations (400 and 700 µmol mol−1) and two irrigation regimes (continuous and intermittent). It was evaluated the number of tillers, plant height, aboveground dry weight (ADW), water use efficiency (WUE), rice yield components, and As and Cd concentration in rice grain. (3) Results: Rice plants were taller and had a higher WUE when cultivated at e[CO2]. The ADW and the rice yield component were not affected by CO2 levels nor water regimes. Intermittent flood regimes had a lower average As concentration. The Cd concentration in the samples in both growing seasons and all treatments was below the limit of quantitation (8.76 μg kg−1). (4) Conclusions: Enhanced CO2 concentration did not affect rice yield, increased the WUE, and reduced As concentration in grains. Regarding water management, the intermittent regime enhanced WUE and promoted a reduction in As concentration in grains.

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Elevated atmospheric CO2 concentration improves water use efficiency and growth of a widespread Cerrado tree species even under soil water deficit

Acta Botanica Brasilica ◽

10.1590/0102-33062018abb0272 ◽

2019 ◽

Vol 33 (3) ◽

pp. 425-436 ◽

Cited By ~ 2

Author(s):

João Paulo Souza ◽

Nayara Magry Jesus Melo ◽

Alessandro Dias Halfeld ◽

Kamilla I. C. Vieira ◽

Bruno Luan Rosa

Keyword(s):

Water Use Efficiency ◽

Soil Water ◽

Water Deficit ◽

Water Use ◽

Tree Species ◽

Co2 Concentration ◽

Atmospheric Co2 ◽

Soil Water Deficit ◽

Elevated Atmospheric Co2 ◽

Use Efficiency

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

Functional Plant Biology ◽

10.1071/fp13067 ◽

2014 ◽

Vol 41 (3) ◽

pp. 244 ◽

Cited By ~ 24

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.

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The sensitivity of stand-scale photosynthesis and transpiration to changes in atmospheric CO2 concentration and climate

Hydrology and Earth System Sciences ◽

10.5194/hess-3-55-1999 ◽

1999 ◽

Vol 3 (1) ◽

pp. 55-69 ◽

Cited By ~ 10

Author(s):

B. Kruijt ◽

C. Barton ◽

A. Rey ◽

P. G. Jarvis

Keyword(s):

Water Stress ◽

Nitrogen Content ◽

Leaf Area ◽

Water Use ◽

N Uptake ◽

Co2 Concentration ◽

Picea Sitchensis ◽

Atmospheric Co2 ◽

Atmospheric Co2 Concentration ◽

Needle Longevity

Abstract. The 3-dimensional forest model MAESTRO was used to simulate daily and annual photosynthesis and transpiration fluxes of forest stands and the sensitivity of these fluxes to potential changes in atmospheric CO2 concentration ([CO2]), temperature, water stress and phenology. The effects of possible feed-backs from increased leaf area and limitations to leaf nutrition were simulated by imposing changes in leaf area and nitrogen content. Two different tree species were considered: Picea sitchensis (Bong.) Carr., a conifer with long needle longevity and large leaf area, and Betula pendula Roth., a broad-leaved deciduous species with an open canopy and small leaf area. Canopy photosynthetic production in trees was predicted to increase with atmospheric [CO2] and length of the growing season and to decrease with increased water stress. Associated increases in leaf area increased production further only in the B. pendula canopy, where the original leaf area was relatively small. Assumed limitations in N uptake affected B. pendula more than P. sitchensis. The effect of increased temperature was shown to depend on leaf area and nitrogen content. The different sensitivities of the two species were related to their very different canopy structure. Increased [CO2] reduced transpiration, but larger leaf area, early leaf growth, and higher temperature all led to increased water use. These effects were limited by feedbacks from soil water stress. The simulations suggest that, with the projected climate change, there is some increase in stand annual `water use efficiency', but the actual water losses to the atmosphere may not always decrease.

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