Net photosynthesis is the largest single flux in the global carbon cycle, but controls over its variability are poorly understood because there is no direct way of measuring it at the ecosystem scale. We report observations of ecosystem carbonyl sulfide (COS) and CO2 fluxes that resolve key gaps in an emerging framework for using concurrent COS and CO2 measurements to quantify terrestrial gross...

The redox landscape of Earth's ocean-atmosphere system has changed dramatically throughout Earth history. Although Earth's protracted oxygenation is undoubtedly the consequence of cyanobacterial oxygenic photosynthesis, the relationship between biological O2 production and Earth's redox evolution remains poorly understood. Existing models for Earth's oxygenation cannot adequately explain the ne...

Coral reef metabolism underpins ecosystem function and is defined by the processes of photosynthesis, respiration, calcification, calcium carbonate dissolution. However, relationships between these physiological at organismal level their interactions with light remain unclear. We examined metabolic rates across a range photosynthesising calcifiers in Caribbean: scleractinian corals Acropora cer...

the production of oxygen radicals in plants under salinity stress conditions in an the important factor for a diminishing of a photosynthesis and a cause fir a decrease in later vegetative growth. in order to study the effects of antioxidants and salinity stress on photosynthetic characteristics and growth in olive, an experiment was conducted in the research greenhouse of tabriz university in ...

Net photosynthesis, growth, and ultraviolet (UV) radiation absorbance were determined for the first leaf of Cucurbita pepo L. exposed to two levels of UV-B irradiation and a UV-B radiation-free control treatment. Absorbance by extracted flavonoid pigments and other UV-B radiation-absorbing compounds from the first leaves increased with time and level of UV-B radiation impinging on leaf surfaces...

A forest ecosystem model (CASTANEA) simulating the carbon balance (canopy photosynthesis, autotrophic and heterotrophic respirations, net ecosystem exchange, wood and root growth) and the water cycle (transpiration, soil evaporation, interception, drainage and soil water status) is tested with data from a young beech forest (Fagus sylvatica L.). For this purpose, the model validity is assessed ...

A soybean suspension culture (SB-P) which can grow photoautotrophically in 5% CO(2) will not grow in ambient CO(2) levels. This elevated CO(2) requirement seems to be due to the additive effects of a number of factors. The in vivo activity of ribulose-1,5-bisphosphate carboxylase (RuBPcase) is much lower in the SB-P cells, compared to soybean plants. This may be due to the low light intensity u...

The combined effect of selenium (Se) foliar spraying and drought was studied for 3 months in two cultivars of potato; Bard and Adora in Ljubljana, Slovenia. Four combinations of treatments were conducted: well-watered plants with and without Se foliar spraying, and drought exposed plants with and without Se foliar spraying. Net photosynthesis, transpiration rate, quantum yield of photosystem II...

Invasion by the exotic annual grass Bromus tectorum has increased the cover and connectivity of fine litter in the sagebrush steppes of western North America. This litter tends to cover biological soil crusts, which could affect their metabolism and growth. To investigate this possible phenomenon, biological soil crusts dominated by either the moss Bryum argenteum or the lichen Diploschistes mu...

In this study, photosynthetic parameters such as the net photosynthesis rate, stomatal conductance, intercellular CO2 concentration, and transpiration rate were examined in selected ginseng varieties and/or lines that are resistant (Yunpoong, HTIR 1, HTIR 2, and HTIR 3) and susceptible (Chunpoong) to high temperature injury (HTI). The net photosynthesis rate increased with the increase in the l...