When efficiency was assumed to be constant, the model overestimated photosynthetic rates in upper canopy layers exposed to direct PPFD, particularly in the unfertilized canopy due to the greater photosynthetic downregulation associated with higher levels of photoprotective (de-epoxidized) xanthophyll cycle pigments in these conditions. As a consequence of increased biomass accumulation, increased CO2 led to larger total pools of TNC, lignin, total carbon, and total nitrogen in Avena with nutrient additions. What are the ecological and evolutionary benefits of the association to the fungus and its invertebrate partner.The role of electrostatics in entomology. Although component estimates are uncertain, about one-half of the total is outside the forest sector. Two California annuals, Avena fatua and Plantago erecta, were grown at ambient and ambient plus 35 Pa atmospheric CO2 in nutrient unamended and amended serpentine soil. Some of the most difficult challenges concern the management of large-scale resources that depend on international cooperation, such as fresh water in international basins or large marine ecosystems. Plants were entrained to a 12-hour-day:12-hour-night light regimen and then monitored or sampled during a subsequent period of constant light. Implications for trends in atmospheric O-2Randerson, J. T., Masiello, C. A., Still, C. J., Rahn, T., Poorter, H., Field, C. B.Herbivore control of annual grassland composition in current and future environmentsPeters, H. A., Cleland, E. E., Mooney, H. A., Field, C. B.Responses of grassland production to single and multiple global environmental changesDukes, J. S., Chiariello, N. R., Cleland, E. E., Moore, L. A., Shaw, M. R., Thayer, S., Tobeck, T., Mooney, H. A., Field, C. B.Interactive effects of elevated CO2, N deposition and climate change on extracellular enzyme activity and soil density fractionation in a California annual grasslandHenry, H. A., Juarez, J. D., Field, C. B., Vitousek, P. M.A technique for identifying the roots of different species in mixed samples using nuclear ribosomal DNAInteractive effects of elevated CO2, N deposition and climate change on plant litter quality in a California annual grasslandHenry, H. A., Cleland, E. E., Field, C. B., Vitousek, P. M.Ammonia-oxidizing bacteria respond to multifactorial global changeHorz, H. P., Barbrook, A., Field, C. B., Bohannan, B. J.Emissions pathways, climate change, and impacts on CaliforniaHayhoe, K., Cayan, D., Field, C. B., Frumhoff, P. C., Maurer, E. P., Miller, N. L., Moser, S. C., Schneider, S. H., Cahill, K. N., Cleland, E. E., Dale, L., Drapek, R., Hanemann, R. M., Kalkstein, L. S., Lenihan, J., Lunch, C. K., Neilson, R. P., Sheridan, S. C., Verville, J. H.Progressive nitrogen limitation of ecosystem responses to rising atmospheric carbon dioxideLuo, Y., Su, B., Currie, W. S., Dukes, J. S., Finzi, A. C., Hartwig, U., Hungate, B., McMurtrie, R. E., Oren, R., Parton, W. J., Pataki, D. E., Shaw, M. R., Zak, D. R., Field, C. B.The carbon balance of an old-growth forest: Building across approachesHungate, B. The net impact of increased CO2 on the carbon balance of terrestrial ecosystems is unclear, however, because elevated CO2 effects on carbon input to soils and plant use of water and nutrients often have contrasting effects on microbial processes.
We argue that forests are characterized by strong competition for light, observed as a race for individual trees to ascend by increasing partitioning toward wood, rather than by growing more leaves, and that this competition stronglyconstrains the allocational plasticity that trees may be capable of. Increases in CO2 and photosynthesis resulted in more seeds per plant (30%) and taller and heavier plants (27% and 41%, respectively).
Foliar δ(13)C became less negative with increasing elevation on the wet east-side lava flows, but not the dry northwest-side flows; it did not reflect patterns of precipitation or presumed water availability.
The rhythms in carbon assimilation and stomatal conductance were closely coupled and persisted for more than a week under constant conditions. Biomass could power either internal combustion or electric vehicles, but the relative land-use efficiency of these two energy pathways is not well quantified. These observations indicate that under conditions where the PAR-dependent system is driven by high intensity red light, the blue light-dependent system has an additive effect on stomatal conductance.The wavelength dependence of photosynthesis and stomatal conductance demonstrates that these processes are not obligatorily coupled and can be controlled by light, independent of prevailing levels of intercellular CO(2). The installations occupy approximately 86,000 ha and more land is allocated for photovoltaic schemes (72 294 ha) than for concentrating solar power (13,604 ha). However, for efficient power generation, solar infrastructures use large amounts of water for construction and operation. The global potential for biomass energy production is large in absolute terms, but it is not enough to replace more than a few percent of current fossil fuel usage. Chris Field is the Perry L. McCarty Director of the Stanford Woods Institute for the Environment. In addition, land-intensive bioenergy scales only with the utilization of vast amounts of land, a resource that is fundamentally limited in supply. We hope you will enjoy our redesigned digital home. Stomatal conductance of these leaves is insensitive to CO(2) concentration and increases in response to high humidity even in the dark.The photocontrol of the functional coupling between photosynthesis and stomatal conductance in the leaf was investigated in gas exchange experiments using monochromatic light provided by lasers.
These measurements allowed the comparison of simultaneous ocean and land net primary production (NPP) responses to a major El Niño to La Niña transition. Most studies classify tree species into categories based on their regeneration requirements. Water-use efficiency, the ratio of photosynthesis to transpiration at light saturation and with a constant water vapor concentration gradient, was not affected by leaf aging or seasonal change.