The influence of oscillatory versus unidirectional flow on the growth and nitrate-uptake rates of juvenile kelp, Laminaria digitata, was determined seasonally in experimental treatments that simulated as closely as possible natural environmental conditions. In winter, regardless of flow condition (oscillatory and unidirectional) or water velocity, no influence of water motion was observed on th...

The role of phytochrome in the induction of nitrate reductase of etiolated field peas (Pisum arvense L.) was examined. Terminal bud nitrate concentration increased in darkness, and the increase correlated with induction of nitrate reductase following brief exposure of intact plants to red, blue, far red, and white lights. Brief light exposure of intact plants stimulated nitrate uptake and induc...

Plants adopt various strategies to fulfill their nitrogen nutrition requirement, the most important being the uptake of nitrate from the soil and its subsequent assimilation in to amino acids. The uptake of nitrate is energy dependent and is an active process involving high affinity and low affinity transport systems. The net uptake of the anion depends upon both influx as well as on its passiv...

The NrtA and NrtB nitrate transporters are paralogous members of the major facilitator superfamily in Aspergillus nidulans. The availability of loss-of-function mutations allowed individual investigation of the specificity and inhibitor sensitivity of both NrtA and NrtB. In this study, growth response tests were carried out at a growth-limiting concentration of nitrate (1 mM) as the sole nitrog...

Improving crop nitrogen (N) use efficiency under salinity is essential for the development of sustainable agriculture in marginal lands. Salicornia europaea is a succulent euhalophyte that can survive under high salinity and N-deficient habitat conditions, implying that a special N assimilation mechanism may exist in this plant. In this study, phenotypic and physiological changes of S. europaea...

Experiments were carried out over 15 mo to assess the net exchange of dissolved inorganic nitrogen (DIN) by the symbiotic coral Acropora palmata (Lamarck) under near-natural environmental conditions. Specimens were enclosed in situ in transparent acrylic chambers and changes in the ambient seawater concentrations of nitrate, nitrite and ammonium determined over 1 h closed incubat ion~ . There w...

Aerosol chemical composition was found to influence nighttime atmospheric chemistry during a series of airborne measurements in northwestern Europe in summer conditions, which has implications for regional air quality and climate. The uptake of dinitrogen pentoxide, γ (N2O5), to particle surfaces was found to be modulated by the amount of water content and ammonium nitrate present in the aeroso...

The objectives of this study were 1) to compare Sonoran Desert streams with other streams in terms of retention efficiency of nitrate; 2) to examine the effects of a flood on nitrate retention and to determine which factors control nitrate retention in the surface stream subsystem in Sycamore Creek, Arizona; and 3) to compare the short-term nutrient addition technique with computations based up...

Nitrate transport in excised corn (Zea mays L.) roots was inhibited by phenylglyoxal, but not by 4,4'-diisothiocyano-2,2'-stilbene disulfonic acid (DIDS) or fluorescein isothiocyanate (FITC). Inhibition of nitrate uptake by a 1-hour treatment with 1 millimolar phenylglyoxal was reversed after 3 hours, which was similar to the time needed for induction of nitrate uptake. If induction of nitrate ...