Plants with citrus variegated chlorosis (CVC), a disease caused by the xylem-limited bacteria Xylella fastidiosa, have leaves with water deficiency symptoms and are associated with decreases on the net photosynthesis and transpiration rates. Using healthy and CVC-affected ‘Pêra’ sweet orange plants on ‘Rangpur’ lime rootstock, the leaf gas exchange variables were measured with an open-gas porta...

Changes in the level of metabolites of the C(4) cycle and reductive pentose phosphate (RPP) pathway were measured simultaneously with induction of photosynthesis in maize (Zea mays L.) to evaluate what may limit carbon assimilation during induction in a C(4) plant.After 20 minutes in the dark, there was an immediate rise in photosynthesis during the first 30 seconds of illumination, followed by...

Anthropogenic forces are projected to lead to warmer temperatures and altered precipitation patterns globally. The impact of these climatic changes on the uptake of carbon by the land surface will, in part, determine the rate and magnitude of these changes. However, there is a great deal of uncertainty in how terrestrial ecosystems will respond to climate in the future. Here, we used a fully fa...

The effect of ozone (03) on ribulose bisphosphate carboxylase/ oxygenase (Rubisco) activity and quantity and net photosynthesis in greenhouse-grown Solanum tuberosum L. cv 'Norland' foliage was studied in relation to oxidant-induced premature senescence. Plants, 26 days old, were exposed to 0.06 to 0.08 microliters per liter 03 from 1000 to 1600 hours for 4 days in a controlled environment cham...

The functional-structural tree model LIGNUM (Perttunen et al., 1996; Perttunen and Sievänen, 2005) has been originally constructed to be applied to single trees. The above ground part of the coniferous and the deciduous trees is modeled with structural units. They are tree segment, branching point and bud. So far the root system is represented with a single variable denoting its mass. LIGNUM co...

Coral reefs are facing rapidly changing environments, but implications for reef ecosystem functioning and important services, such as productivity, are difficult to predict. Comparative investigations on coral reefs that are naturally exposed to differing environmental settings can provide essential information in this context. One prevalent phenomenon regularly introducing alterations in water...

Quantifying impacts of ecological disturbance on ecosystem carbon and water fluxes will improve predictive understanding of biosphere—atmosphere feedbacks. Tree mortality caused by mountain pine bark beetles (Dendroctonus ponderosae) is hypothesized to decrease photosynthesis and water flux to the atmosphere while increasing respiration at a rate proportional to mortality. This work uses data f...

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. Net photosynthesis and stomatal conductance were measured in attached leaves of Malva parviflora L. as a function of photon irradiance at 457.9 and 640.0 nanometers.Photosynthetic rates and quantum yiel...

We investigated diurnal and seasonal changes in carbon acquisition and partitioning of recently assimilated carbon in fast- and slow-growing families of loblolly pine (Pinus taeda L.) to determine whether fast-growing families exhibited greater carbon gain at the leaf level. Since planting on a xeric infertile site in Scotland County, NC, USA in 1993, five Atlantic Coastal Plain (ACP) and five ...

Plant tolerance to herbivory is a key approach for managing pests. In alfalfa, Medicago sativa, the potato leafhopper, Empoasca fabae, is a major pest as a result of the cascade of plant responses to piercing-sucking injury. To identify tolerance to its injury based on alfalfa physiology, experiments were conducted in the field and greenhouse. In our comparison of the response of field-grown al...