Water use efficiency

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From Climate Change Reconsidered, a work of the Nongovernmental International Panel on Climate Change
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Another major consequence of atmospheric CO2 enrichment is that plants exposed to elevated levels of atmospheric CO2 generally do not open their leaf stomatal pores—through which they take in carbon dioxide and give off water vapor—as wide as they do at lower CO2 concentrations and tend to produce fewer of these pores per unit area of leaf surface. Both changes tend to reduce most plants’ rates of water loss by transpiration. The amount of carbon they gain per unit of water lost—or water-use efficiency—therefore typically rises, increasing their ability to withstand drought. In this section, we explore the phenomena of water use efficiency as it pertains to agricultural, grassland, and woody species.
Another major consequence of atmospheric CO2 enrichment is that plants exposed to elevated levels of atmospheric CO2 generally do not open their leaf stomatal pores—through which they take in carbon dioxide and give off water vapor—as wide as they do at lower CO2 concentrations and tend to produce fewer of these pores per unit area of leaf surface. Both changes tend to reduce most plants’ rates of water loss by transpiration. The amount of carbon they gain per unit of water lost—or water-use efficiency—therefore typically rises, increasing their ability to withstand drought. In this section, we explore the phenomena of water use efficiency as it pertains to agricultural, grassland, and woody species.
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== References ==
== References ==
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Climate Change Reconsidered: Website of the Nongovernmental International Panel on Climate Change. http://www.nipccreport.org/archive/archive.html
Conley, M.M., Kimball, B.A., Brooks, T.J., Pinter Jr., P.J., Hunsaker, D.J., Wall, G.W., Adams, N.R., LaMorte, R.L., Matthias, A.D., Thompson, T.L., Leavitt, S.W., Ottman, M.J., Cousins, A.B. and Triggs, J.M. 2001. CO2 enrichment increases water-use efficiency in sorghum. New Phytologist 151: 407-412.
Conley, M.M., Kimball, B.A., Brooks, T.J., Pinter Jr., P.J., Hunsaker, D.J., Wall, G.W., Adams, N.R., LaMorte, R.L., Matthias, A.D., Thompson, T.L., Leavitt, S.W., Ottman, M.J., Cousins, A.B. and Triggs, J.M. 2001. CO2 enrichment increases water-use efficiency in sorghum. New Phytologist 151: 407-412.

Current revision as of 16:25, 2 May 2011

From Climate Change Reconsidered, a work of the Nongovernmental International Panel on Climate Change

Another major consequence of atmospheric CO2 enrichment is that plants exposed to elevated levels of atmospheric CO2 generally do not open their leaf stomatal pores—through which they take in carbon dioxide and give off water vapor—as wide as they do at lower CO2 concentrations and tend to produce fewer of these pores per unit area of leaf surface. Both changes tend to reduce most plants’ rates of water loss by transpiration. The amount of carbon they gain per unit of water lost—or water-use efficiency—therefore typically rises, increasing their ability to withstand drought. In this section, we explore the phenomena of water use efficiency as it pertains to agricultural, grassland, and woody species.


Contents

Agricultural Species

In the study of Serraj et al. (1999), soybeans grown at 700 ppm CO2 displayed 10 to 25 percent reductions in total water loss while simultaneously exhibiting increases in dry weight of as much as 33 percent. Thus, elevated CO2 significantly increased the water-use efficiencies of the studied plants. Likewise, Garcia et al. (1998) determined that spring wheat grown at 550 ppm CO2 exhibited a water-use efficiency that was about one-third greater than that exhibited by plants grown at 370 ppm CO2. Similarly, Hakala et al. (1999) reported that twice-ambient CO2 concentrations increased the water-use efficiency of spring wheat by 70 to 100 percent, depending on experimental air temperature. In addition, Hunsaker et al. (2000) reported CO2-induced increases in water-use efficiency for field-grown wheat that were 20 and 10 percent higher than those displayed by ambiently grown wheat subjected to high and low soil nitrogen regimes, respectively. Also, pea plants grown for two months in growth chambers receiving atmospheric CO2 concentrations of 700 ppm displayed an average water-use efficiency that was 27 percent greater than that exhibited by ambiently grown control plants (Gavito et al., 2000).

In some cases, the water-use efficiency increases caused by atmospheric CO2 enrichment are spectacularly high. De Luis et al. (1999), for example, demonstrated that alfalfa plants subjected to atmospheric CO2 concentrations of 700 ppm had water-use efficiencies that were 2.6 and 4.1 times greater than those displayed by control plants growing at 400 ppm CO2 under water-stressed and well-watered conditions, respectively. Also, when grown at an atmospheric CO2 concentration of 700 ppm, a 2.7-fold increase in water-use efficiency was reported by Malmstrom and Field (1997) for oats infected with the barley yellow dwarf virus.

In addition to enhancing the water-use efficiencies of agricultural C3 crops, as reported in the preceding paragraphs, elevated CO2 also enhances the water-use efficiencies of crops possessing alternate carbon fixation pathways. Maroco et al. (1999), for example, demonstrated that maize—a C4 crop—grown for 30 days at an atmospheric CO2 concentration of 1,100 ppm exhibited an intrinsic water-use efficiency that was 225 percent higher than that of plants grown at 350 ppm CO2. In addition, Conley et al. (2001) reported that a 200-ppm increase in the air’s CO2 content boosted the water-use efficiency of field-grown sorghum by 9 and 19 percent under well-watered and water-stressed conditions, respectively. Also, Zhu et al. (1999) reported that pineapple—a CAM plant—grown at 700 ppm CO2 exhibited water-use efficiencies that were always significantly greater than those displayed by control plants grown at 350 ppm CO2 over a range of growth temperatures.

It is clear from the studies above that as the CO2 content of the air continues to rise, earth’s agricultural species will respond favorably by exhibiting increases in water-use efficiency. It is likely that food and fiber production will increase on a worldwide basis, even in areas where productivity is severely restricted due to limited availability of soil moisture.

Additional information on this topic, including reviews of newer publications as they become available, can be found at http://www.co2science.org/ subject/w/wateruseag.php.


Grassland Species

In the study of Grunzweig and Korner (2001), model grasslands representative of the semi-arid Negev of Israel, which were grown for five months at atmospheric CO2 concentrations of 440 and 600 ppm, exhibited cumulative water-use efficiencies that were 17 and 28 percent greater, respectively, than control communities grown at 280 ppm CO2. Similarly, Szente et al. (1998) reported a doubling of the atmospheric CO2 concentration increased the water-use efficiency of two C3 grasses and two broad-leaved species common to the loess grasslands of Budapest by 72 and 266 percent, respectively. In addition, Leymarie et al. (1999) calculated that twice-ambient CO2 concentrations increased the water-use efficiency of the herbaceous weedy species Arabidopsis thaliana by 41 and 120 percent under well-watered and water-stressed conditions, respectively. Other CO2-induced increases in C3 plant water-use efficiency have been documented by Clark et al. (1999) for several New Zealand pasture species and Roumet et al. (2000) for various Mediterranean herbs.

Elevated CO2 also has been shown to substantially increase the water-use efficiency of C4 grassland species. Adams et al. (2000), for example, reported that twice-ambient CO2 concentrations enhanced the daily water-use efficiency of a C4 tallgrass prairie in Kansas, USA, dominated by Andropogon gerardii. LeCain and Morgan (1998) also documented enhanced water-use efficiencies for six different C4 grasses grown with twice-ambient CO2 concentrations. Likewise, Seneweera et al. (1998) reported that a 650-ppm increase in the air’s CO2 content dramatically increased the water-use efficiency of the perennial C4 grass Panicum coloratum.

As the air’s CO2 content continues to rise, nearly all of earth’s grassland species—including both C3 and C4 plants—will likely experience increases in water-use efficiency. Concomitantly, the productivity of the world’s grasslands should increase, even if available moisture decreases in certain areas. Moreover, such CO2-induced increases in water-use efficiency will likely allow grassland species to expand their ranges into desert areas where they previously could not survive due to lack of sufficient moisture.

Additional information on this topic, including reviews of newer publications as they become available, can be found at http://www.co2science.org/ subject/w/waterusegrass.php.


Woody Species

The effect of elevated atmospheric CO2 concentrations on the water-use efficiencies of trees is clearly positive, having been documented in a number of different single-species studies of longleaf pine (Runion et al., 1999), red oak (Anderson and Tomlinson, 1998), scrub oak (Lodge et al., 2001), silver birch (Rey and Jarvis, 1998), beech (Bucher-Wallin et al., 2000; Egli et al., 1998), sweetgum (Gunderson et al., 2002; Wullschleger and Norby, 2001), and spruce (Roberntz and Stockfors, 1998). Likewise, in a multi-species study performed by Tjoelker et al. (1998), seedlings of quaking aspen, paper birch, tamarack, black spruce, and jack pine, which were grown at 580 ppm CO2 for three months, displayed water-use efficiencies that were 40 to 80 percent larger than those exhibited by their respective controls grown at 370 ppm CO2.

Similar results are also obtained when trees are exposed to different environmental stresses. In a study conducted by Centritto et al. (1999), for example, cherry seedlings grown at twice-ambient levels of atmospheric CO2 displayed water-use efficiencies that were 50 percent greater than their ambient controls, regardless of soil moisture status. And in the study of Wayne et al. (1998), yellow birch seedlings grown at 800 ppm CO2 had water-use efficiencies that were 52 and 94 percent greater than their respective controls, while simultaneously subjected to uncharacteristically low and high air temperature regimes.

In some parts of the world, perennial woody species have been exposed to elevated atmospheric CO2 concentrations for decades, due to their proximity to CO2-emitting springs and vents in the earth, allowing scientists to assess the long-term effects of this phenomenon. In Venezuela, for example, the water-use efficiency of a common tree exposed to a lifetime atmospheric CO2 concentration of approximately 1,000 ppm rose 2-fold and 19-fold during the local wet and dry seasons, respectively (Fernandez et al., 1998). Similarly, Bartak et al. (1999) reported that 30-year-old Arbutus unedo trees growing in central Italy at a lifetime atmospheric CO2 concentration around 465 ppm exhibited water-use efficiencies that were 100 percent greater than control trees growing at a lifetime CO2 concentration of 355 ppm. In addition, two species of oaks in central Italy that had been growing for 15 to 25 years at an atmospheric CO2 concentration ranging from 500 to 1,000 ppm displayed “such marked increases in water-use efficiency under elevated CO2,” in the words of the scientists who studied them, that this phenomenon “might be of great importance in Mediterranean environments in the perspective of global climate change” (Blaschke et al., 2001; Tognetti et al., 1998). Thus, the long-term effects of elevated CO2 concentrations on water-use efficiency are likely to persist and increase with increasing atmospheric CO2 concentrations.

In some cases, scientists have looked to the past and determined the positive impact the historic rise in the air’s CO2 content has already had on plant water-use efficiency. Duquesnay et al. (1998), for example, used tree-ring data derived from beech trees to determine that over the past century the water-use efficiency of such trees in north-eastern France increased by approximately 33 percent. Similarly, Feng (1999) used tree-ring chronologies derived from a number of trees in western North America to calculate a 10 to 25 percent increase in tree water-use efficiency from 1750 to 1970, during which time the atmospheric CO2 concentration rose by approximately 16 percent. In another study, Knapp et al. (2001) developed tree-ring chronologies from western juniper stands located in Oregon, USA, for the past century, determining that growth recovery from drought was much greater in the latter third of their chronologies (1964-1998) than it was in the first third (1896-1930). In this case, the authors suggested that the greater atmospheric CO2 concentrations of the latter period allowed the trees to more quickly recover from water stress. Finally, Beerling et al. (1998) grew Gingko saplings at 350 and 650 ppm CO2 for three years, finding that elevated atmospheric CO2 concentrations reduced leaf stomatal densities to values comparable to those measured on fossilized Gingko leaves dating back to the Triassic and Jurassic periods, implying greater water-use efficiencies for those times too.

On another note, Prince et al. (1998) demonstrated that rain-use efficiency, which is similar to water-use efficiency, slowly increased in the African Sahel from 1982 to 1990, while Nicholson et al. (1998) observed neither an increase nor a decrease in this parameter from 1980 to 1995 for the central and western Sahel.

In summary, it is clear that as the CO2 content of the air continues to rise, nearly all of earth’s trees will respond favorably by exhibiting increases in water-use efficiency. It is thus likely that as time progresses, earth’s woody species will expand into areas where they previously could not exist due to limiting amounts of available moisture. Therefore, one can expect the earth to become a greener biospheric body with greater carbon sequestering capacity as the atmospheric CO2 concentration continues to rise.

Additional information on this topic, including reviews of newer publications as they become available, can be found at http://www.co2science.org/ subject/w/waterusetrees.php.


References

Climate Change Reconsidered: Website of the Nongovernmental International Panel on Climate Change. http://www.nipccreport.org/archive/archive.html

Conley, M.M., Kimball, B.A., Brooks, T.J., Pinter Jr., P.J., Hunsaker, D.J., Wall, G.W., Adams, N.R., LaMorte, R.L., Matthias, A.D., Thompson, T.L., Leavitt, S.W., Ottman, M.J., Cousins, A.B. and Triggs, J.M. 2001. CO2 enrichment increases water-use efficiency in sorghum. New Phytologist 151: 407-412.

De Luis, J., Irigoyen, J.J. and Sanchez-Diaz, M. 1999. Elevated CO2 enhances plant growth in droughted N2-fixing alfalfa without improving water stress. Physiologia Plantarum 107: 84-89.

Garcia, R.L., Long, S.P., Wall, G.W., Osborne, C.P., Kimball, B.A., Nie, G.Y., Pinter Jr., P.J., LaMorte, R.L. and Wechsung, F. 1998. Photosynthesis and conductance of spring-wheat leaves: field response to continuous free-air atmospheric CO2 enrichment. Plant, Cell and Environment 21: 659-669.

Gavito, M.E., Curtis, P.S., Mikkelsen, T.N. and Jakobsen, I. 2000. Atmospheric CO2 and mycorrhiza effects on biomass allocation and nutrient uptake of nodulated pea (Pisum sativum L.) plants. Journal of Experimental Botany 52: 1931-1938.

Hakala, K., Helio, R., Tuhkanen, E. and Kaukoranta, T. 1999. Photosynthesis and Rubisco kinetics in spring wheat and meadow fescue under conditions of simulated climate change with elevated CO2 and increased temperatures. Agricultural and Food Science in Finland 8: 441-457.

Hunsaker, D.J., Kimball. B.A., Pinter Jr., P.J., Wall, G.W., LaMorte, R.L., Adamsen, F.J., Leavitt, S.W., Thompson, T.L., Matthias, A.D. and Brooks, T.J. 2000. CO2 enrichment and soil nitrogen effects on wheat evapotranspiration and water use efficiency. Agricultural and Forest Meteorology 104: 85-105.

Malmstrom, C.M. and Field, C.B. 1997. Virus-induced differences in the response of oat plants to elevated carbon dioxide. Plant, Cell and Environment 20: 178-188.

Maroco, J.P., Edwards, G.E. and Ku, M.S.B. 1999. Photosynthetic acclimation of maize to growth under elevated levels of carbon dioxide. Planta 210: 115-125.

Serraj, R., Allen Jr., L.H. and Sinclair, T.R. 1999. Soybean leaf growth and gas exchange response to drought under carbon dioxide enrichment. Global Change Biology 5: 283-291.

Zhu, J., Goldstein, G. and Bartholomew, D.P. 1999. Gas exchange and carbon isotope composition of Ananas comosus in response to elevated CO2 and temperature. Plant, Cell and Environment 22: 999-1007.

Adams, N.R., Owensby, C.E. and Ham, J.M. 2000. The effect of CO2 enrichment on leaf photosynthetic rates and instantaneous water use efficiency of Andropogon gerardii in the tallgrass prairie. Photosynthesis Research 65: 121-129.

Clark, H., Newton, P.C.D. and Barker, D.J. 1999. Physiological and morphological responses to elevated CO2 and a soil moisture deficit of temperate pasture species growing in an established plant community. Journal of Experimental Botany 50: 233-242.

Grunzweig, J.M. and Korner, C. 2001. Growth, water and nitrogen relations in grassland model ecosystems of the semi-arid Negev of Israel exposed to elevated CO2. Oecologia 128: 251-262.

LeCain, D.R. and Morgan, J.A. 1998. Growth, gas exchange, leaf nitrogen and carbohydrate concentrations in NAD-ME and NADP-ME C4 grasses grown in elevated CO2. Physiologia Plantarum 102: 297-306.

Leymarie, J., Lasceve, G. and Vavasseur, A. 1999. Elevated CO2 enhances stomatal responses to osmotic stress and abscisic acid in Arabidopsis thaliana. Plant, Cell and Environment 22: 301-308.

Roumet, C., Garnier, E., Suzor, H., Salager, J.-L. and Roy, J. 2000. Short and long-term responses of whole-plant gas exchange to elevated CO2 in four herbaceous species. Environmental and Experimental Botany 43: 155-169.

Seneweera, S.P., Ghannoum, O. and Conroy, J. 1998. High vapor pressure deficit and low soil water availability enhance shoot growth responses of a C4 grass (Panicum coloratum cv. Bambatsi) to CO2 enrichment. Australian Journal of Plant Physiology 25: 287-292.

Szente, K., Nagy, Z. and Tuba, Z. 1998. Enhanced water use efficiency in dry loess grassland species grown at elevated air CO2 concentration. Photosynthetica 35: 637-640. Anderson, P.D. and Tomlinson, P.T. 1998. Ontogeny affects response of northern red oak seedlings to elevated CO2 and water stress. I. Carbon assimilation and biomass production. New Phytologist 140: 477-491.

Bartak, M., Raschi, A. and Tognetti, R. 1999. Photosynthetic characteristics of sun and shade leaves in the canopy of Arbutus unedo L. trees exposed to in situ long-term elevated CO2. Photosynthetica 37: 1-16.

Beerling, D.J., McElwain, J.C. and Osborne, C.P. 1998. Stomatal responses of the ‘living fossil’ Ginkgo biloba L. to changes in atmospheric CO2 concentrations. Journal of Experimental Botany 49: 1603-1607.

Blaschke, L., Schulte, M., Raschi, A., Slee, N., Rennenberg, H. and Polle, A. 2001. Photosynthesis, soluble and structural carbon compounds in two Mediterranean oak species (Quercus pubescens and Q. ilex) after lifetime growth at naturally elevated CO2 concentrations. Plant Biology 3: 288-298.

Bucher-Wallin, I.K., Sonnleitner, M.A., Egli, P., Gunthardt-Goerg, M.S., Tarjan, D., Schulin, R. and Bucher, J.B. 2000. Effects of elevated CO2, increased nitrogen deposition and soil on evapotranspiration and water use efficiency of spruce-beech model ecosystems. Phyton 40: 49-60.

Centritto, M., Lee, H.S.J. and Jarvis, P.G. 1999. Interactive effects of elevated [CO2] and drought on cherry (Prunus avium) seedlings. I. Growth, whole-plant water use efficiency and water loss. New Phytologist 141: 129-140.

Duquesnay, A., Breda, N., Stievenard, M. and Dupouey, J.L. 1998. Changes of tree-ring d13C and water-use efficiency of beech (Fagus sylvatica L.) in north-eastern France during the past century. Plant, Cell and Environment 21: 565-572.

Egli, P., Maurer, S., Gunthardt-Goerg, M.S. and Korner, C. 1998. Effects of elevated CO2 and soil quality on leaf gas exchange and aboveground growth in beech-spruce model ecosystems. New Phytologist 140: 185-196.

Feng, X. 1999. Trends in intrinsic water-use efficiency of natural trees for the past 100-200 years: A response to atmospheric CO2 concentration. Geochimica et Cosmochimica Acta 63: 1891-1903.

Fernandez, M.D., Pieters, A., Donoso, C., Tezara, W., Azuke, M., Herrera, C., Rengifo, E. and Herrera, A. 1998. Effects of a natural source of very high CO2 concentration on the leaf gas exchange, xylem water potential and stomatal characteristics of plants of Spatiphylum cannifolium and Bauhinia multinervia. New Phytologist 138: 689-697.

Gunderson, C.A., Sholtis, J.D., Wullschleger, S.D., Tissue, D.T., Hanson, P.J. and Norby, R.J. 2002. Environmental and stomatal control of photosynthetic enhancement in the canopy of a sweetgum (Liquidambar styraciflua L.) plantation during 3 years of CO2 enrichment. Plant, Cell and Environment 25: 379-393.

Knapp, P.A., Soule, P.T. and Grissino-Mayer, H.D. 2001. Post-drought growth responses of western juniper (Junipers occidentalis var. occidentalis) in central Oregon. Geophysical Research Letters 28: 2657-2660.

Lodge, R.J., Dijkstra, P., Drake, B.G. and Morison, J.I.L. 2001. Stomatal acclimation to increased CO2 concentration in a Florida scrub oak species Quercus myrtifolia Willd. Plant, Cell and Environment 24: 77-88.

Nicholson, S.E., Tucker, C.J. and Ba, M.B. 1998. Desertification, drought, and surface vegetation: An example from the West African Sahel. Bulletin of the American Meteorological Society 79: 815-829.

Prince, S.D., Brown De Colstoun, E. and Kravitz, L.L. 1998. Evidence from rain-use efficiencies does not indicate extensive Sahelian desertification. Global Change Biology 4: 359-374.

Rey, A. and Jarvis, P.G. 1998. Long-term photosynthetic acclimation to increased atmospheric CO2 concentration in young birch (Betula pendula) trees. Tree Physiology 18: 441-450.

Roberntz, P. and Stockfors, J. 1998. Effects of elevated CO2 concentration and nutrition on net photosynthesis, stomatal conductance and needle respiration of field-grown Norway spruce trees. Tree Physiology 18: 233-241.

Runion, G.B., Mitchell, R.J., Green, T.H., Prior, S.A., Rogers, H.H. and Gjerstad, D.H. 1999. Longleaf pine photosynthetic response to soil resource availability and elevated atmospheric carbon dioxide. Journal of Environmental Quality 28: 880-887.

Tjoelker, M.G., Oleksyn, J. and Reich, P.B. 1998. Seedlings of five boreal tree species differ in acclimation of net photosynthesis to elevated CO2 and temperature. Tree Physiology 18: 715-726.

Tognetti, R., Johnson, J.D., Michelozzi, M. and Raschi, A. 1998. Response of foliar metabolism in mature trees of Quercus pubescens and Quercus ilex to long-term elevated CO2. Environmental and Experimental Botany 39: 233-245.

Wayne, P.M., Reekie, E.G. and Bazzaz, F.A. 1998. Elevated CO2 ameliorates birch response to high temperature and frost stress: implications for modeling climate-induced geographic range shifts. Oecologia 114: 335-342.

Wullschleger, S.D. and Norby, R.J. 2001. Sap velocity and canopy transpiration in a sweetgum stand exposed to free-air CO2 enrichment (FACE). New Phytologist 150: 489-498.


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