Understanding biogeochemical cycles and especially carbon budgets is clue to validate global change models in the present and near future. As a consequence, sinks and sources of carbon in the world are being studied. One of those sinks is the non-well known behavior of the planet vegetation which involves the processes of photosynthesis and respiration. Carbon sequestration rates are highly rel...

While natural photosynthesis serves as the model system for efficient charge separation and decoupling of redox reactions, bio-inspired artificial systems typically lack applicability owing to synthetic challenges and structural complexity. We present herein a simple and inexpensive system that, under solar irradiation, forms highly reductive radicals in the presence of an electron donor, with ...

Levels of starch and sugars, and the activities of amylase and starch phosphorylase were measured in expanding leaves harvested in early morning and early evening during the growth of pepper (Capsicum annuum L.; cv ;Bellboy') plants. The differences between starch levels 1 hour after dawn and 1 hour after dusk increased during the period of initial fruit expansion. This diurnal starch differenc...

In large regions of the open ocean, iron is a limiting resource for phytoplankton. The reduction of iron quota and the recycling of internal iron pools are among the diverse strategies that phytoplankton have evolved to allow them to grow under chronically low ambient iron levels. Phytoplankton species also have evolved strategies to cope with sporadic iron supply such as long-term storage of i...

Initial observations of what are now accepted as clockcontrolled processes in cyanobacteria were reported in the mid-1980s by scientists working with natural isolates of diverse species (Ditty et al. 2003). Diurnal rhythms in nitrogen fixation, photosynthesis, amino acid uptake, and cell division were not immediately interpreted as the consequence of an endogenous biological clock. At least two...

The photosynthetic and respiratory rates of 5- to 7-year-old aspen stems (Populus tremuloides Michx.) were monitored in the field for 1 year to determine the seasonal patterns. The stem was not capable of net photosynthesis, but the respiratory CO(2) loss from the stem was reduced by 0 to 100% depending on the time of year and the level of illumination as a result of bark photosynthesis. The mo...

0378-1127/$ see front matter 2012 Elsevier B.V. A http://dx.doi.org/10.1016/j.foreco.2012.02.017 ⇑ Corresponding author. Tel.: +1 334 844 1040; fax E-mail address: [email protected] (L.J. Samuels Longleaf pine (Pinus palustris Mill.), a species that once dominated the southeastern USA, is considered to be more drought tolerant than the principle plantation species in the South, loblolly pine (...

Accurately representing complex land-surface processes balancing complexity and realism remains one challenge that the weather modelling community is facing nowadays. In this study, a photosynthesis-based Gas-exchange Evapotranspiration Model (GEM) is integrated into the Noah land-surface model replacing the traditional Jarvis scheme for estimating the canopy resistance and transpiration. Using...

Studies were conducted that supported the hypothesis that the mutation to the psbA plastid gene that confers S-triazine resistance (R) in Brassica napus also results in an altered diurnal pattern of photosynthetic carbon assimilation (A) relative to that of the susceptible (S) wild type, and that these patterns change over the ontogeny of a plant. Photosynthetic photon flux density, under close...

the seasonal and diurnal variations in the incidence of hypertension, cerebrovascular accident, coronary heart disease were well documented, but the relation between season and daytime on the onset of aneurysmal subarachnoid hemorrhage (asah) was a subject of controversy. in the present study we aimed to evaluate the role of season of year and diurnal changes on the onset of asah. the time was ...