Net photosynthetic rates (Pns) in leaves were compared between rice plants grown in ambient air control and free-air CO2 enrichment (FACE, about 200 micromol mol(-1) above ambient) treatment rings. When measured at the same CO2 concentration, the Pn of FACE leaves decreased significantly, indicating that photosynthetic acclimation to high CO2 occurs. Although stomatal conductance (Gs) in FACE l...

In order to extend the applicability of the regioselective enzymatic carboxylation of phenols, the substrate scope of o-benzoic acid (de)carboxylases has been investigated towards complex molecules with an emphasis on flavouring agents and polyphenols possessing antioxidant properties. o-Hydroxycarboxylic acid products were obtained with perfect regioselectivity, in moderate to excellent yields...

One-year-old jack pine (Pinus banksiana Lamb.) and current-year white birch (Betula papyrifera Marsh.) seedlings were grown in ambient (360 ppm) or twice ambient (720 ppm) atmospheric CO2 concentration ([CO2]) and at three soil temperatures (Tsoil = 7, 17 and 27 degrees C initially, increased to 10, 20 and 30 degrees C two months later, respectively) in a greenhouse for 4 months. In situ foliar...

A mathematical model is developed which can be used to predict in vivo carbon isotope fractionations associated with carbon fixation in plants in terms of diffusion, CO(2) hydration, and carboxylation components. This model also permits calculation of internal CO(2) concentration for comparison with results of gas-exchange experiments. The isotope fractionations associated with carbon fixation ...

Urea carboxylase, an avidin-sensitive enzyme catalyzing the ATP-dependent carboxylation of urea, has been shown to catalyze this reaction in a sequence of at least two steps. In the presence of all of the required carboxylation cofactors except urea, an enzyme-CO2 complex is formed. This complex was isolated by Sephadex chromatography and was capable, in the absence of added cofactors, of trans...

Photosynthetic capacity, determined by light harvesting and carboxylation reactions, is a key plant trait that determines the rate of photosynthesis; however, in Earth System Models (ESMs) at a reference temperature, it is either a fixed value for a given plant functional type or derived from a linear function of leaf nitrogen content. In this study, we conducted a comprehensive analysis that c...

The two carboxylation reactions performed by phosphoenolpyruvate carboxylase (PEPC) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) are vital in the fixation of inorganic carbon for C4 plants. The abundance of PEPC is substantially elevated in C4 leaves, while the location of Rubisco is restricted to one of two chloroplast types. These differences compared with C3 leaves have been...

The photosynthetic responses to moderately high temperatures (38 degrees C, imposed at 21% or 2% O(2) in air and 1500 mumol m(-2) s(-1)) were compared in wheat (Triticum aestivum L.) cultivars grown in northern regions of Ukraine and expected to be relatively sensitive to high temperatures ('North' cultivars) and in cultivars grown in southern regions and expected to be relatively heat-tolerant...

Aquaponics is a promising cultivation technique for combined production of crops and fish, on the condition tackling certain nutrients deficiencies. The aim present study was to examine limitations imposed by system spinach (Spinacia oleracea) growth functional performance identify minimum nutrient supplementation their optimization. Spinach co-cultivated with red tilapia under three treatments...

A regular (cv. Thothapuri) and an irregular (cv. Langra) bearing cultivar of mango were selected to study the gas exchange parameters such as photosynthesis, stomatal conductance and internal carbon dioxide concentrations in ̄owering and non̄owering branches. Photosynthetic rates at different carbon dioxide concentrations were also recorded in both the branches to calculate the carboxylation ef®...