期刊
ANNALS OF BOTANY
卷 111, 期 3, 页码 467-477出版社
OXFORD UNIV PRESS
DOI: 10.1093/aob/mcs268
关键词
Elevated CO2; FACE; fertilization; leaf gas exchange; nitrogen; optimal stomatal conductance; pine; Pinus taeda; water-use efficiency
资金
- US Department of Agriculture [2011-67003-30222, FS-AGRMNT 09-CA-11330140-059]
- US Department of Energy (DOE) through the Office of Biological and Environmental Research (BER) Terrestrial Carbon Processes (TCP) program [DE-FG02-95ER62083, DE-FC02-06ER64156]
- National Science Foundation [NSF-EAR-10-13339, NSF-AGS-11-02227, NSF-CBET-10-33467]
- Binational Agricultural Research Development fund [IS-4374-11C]
- Directorate For Geosciences
- Division Of Earth Sciences [1013339] Funding Source: National Science Foundation
- Div Atmospheric & Geospace Sciences
- Directorate For Geosciences [1102227] Funding Source: National Science Foundation
Background and Aims Water and nitrogen (N) are two limiting resources for biomass production of terrestrial vegetation. Water losses in transpiration (E) can be decreased by reducing leaf stomatal conductance (g(s)) at the expense of lowering CO2 uptake (A), resulting in increased water-use efficiency. However, with more N available, higher allocation of N to photosynthetic proteins improves A so that N-use efficiency is reduced when g(s) declines. Hence, a trade-off is expected between these two resource-use efficiencies. In this study it is hypothesized that when foliar concentration (N) varies on time scales much longer than g(s), an explicit complementary relationship between the marginal water- and N-use efficiency emerges. Furthermore, a shift in this relationship is anticipated with increasing atmospheric CO2 concentration (c(a)). Methods Optimization theory is employed to quantify interactions between resource-use efficiencies under elevated c(a) and soil N amendments. The analyses are based on marginal water- and N-use efficiencies, lambda = (partial derivative A/partial derivative g(s))/(partial derivative E/partial derivative g(s)) and eta = partial derivative A/partial derivative N, respectively. The relationship between the two efficiencies and related variation in intercellular CO2 concentration (c(i)) were examined using A/c(i) curves and foliar N measured on Pinus taeda needles collected at various canopy locations at the Duke Forest Free Air CO2 Enrichment experiment (North Carolina, USA). Key Results Optimality theory allowed the definition of a novel, explicit relationship between two intrinsic leaf-scale properties where eta is complementary to the square-root of lambda. The data support the model predictions that elevated c(a) increased eta and lambda, and at given c(a) and needle age-class, the two quantities varied among needles in an approximately complementary manner. Conclusions The derived analytical expressions can be employed in scaling-up carbon, water and N fluxes from leaf to ecosystem, but also to derive transpiration estimates from those of eta, and assist in predicting how increasing c(a) influences ecosystem water use.
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