the influence of salinity on the different polyamine fractions (free, conjugated, and bound) was compared in a natrophilic halophyte (beta vulgaris l. cv. ic) and a salt sensitive glycophyte (nicotiana rustica l. cv. basmas). low-level salinity (25 mm nacl) and high salinity (150 and 50 mm nacl for sugar beet and tobacco, respectively) were supplied in hydroponics. under low salinity shoot dry ...

The unicellular cyanobacterium Cyanothece sp. American Type Culture Collection (ATCC) 51142 is capable of performing oxygenic photosynthesis during the day and microoxic nitrogen fixation at night. These mutually exclusive processes are possible only by temporal separation by circadian clock or another cellular program. We report identification of a temperature-dependent ultradian metabolic rhy...

Fossil fuel combustion has increased atmospheric CO2 by≈ 115 μmol mol 1 since 1750 and decreased its carbon isotope composition (δC) by 1.7–2‰ (the C Suess effect). Because carbon is stored in the terrestrial biosphere for decades and longer, the δC of CO2 released by terrestrial ecosystems is expected to differ from the δC of CO2 assimilated by land plants during photosynthesis. This isotopic ...

This study presents nearly continuous air-sea CO2 flux for 7 years using the eddy covariance method for nearshore water near San Diego, California, as well as identifying environmental processes that appear to control temporal variations in air-sea CO2 flux at different time scales using time series decomposition. Monthly variations in CO2 uptake are shown to be positively influenced by photosy...

1 We compiled from literature annually integrated air-water fluxes of carbon 2 dioxide (CO2) computed from field measurements, in 20 coastal European 3 environments that were gathered into 3 main ecosystems: inner estuaries, upwelling 4 continental shelves and non-upwelling continental shelves. The comparison of annual 5 cycles of the partial pressure of CO2 (pCO2) in 5 contrasting continental ...

BACKGROUND The terrestrial land surface in West Africa is made up of several types of savanna ecosystems differing in land use changes which modulate gas exchanges between their vegetation and the overlying atmosphere. This study compares diurnal and seasonal estimates of CO2 fluxes from three contrasting ecosystems, a grassland, a mixture of fallow and cropland, and nature reserve in the Sudan...

The net impact of human nitrogen (N) fixation on climate (ignoring short-lived components) mainly depends on the magnitude of the warming effect of (direct and indirect) nitrous oxide (N2O) emissions and the cooling effect of N-induced carbon dioxide (CO2) uptake. N-induced CO2 uptake is caused by anthropogenic N deposition which increases net primary production (NPP) in N-limited ecosystems an...

Sod culture (SC) and no tillage (NT) are modern orchard management systems, two different bases for the sustainable development production of citrus orchards in Taiwan. However, there is information about efficiency either NT or SC on photosynthetic physiology farmed under seasons varying light intensities. The objective this study was to clarify impacts eco-friendly farming apparatus an import...