Each year, millions of hatchery-raised fish are stocked into streams and rivers worldwide, yet the effects of hatchery-raised fish on stream nutrient cycles have seldom been examined. We quantified the influence of supplemental nonnative fish stocking, a widespread recreational fishery management practice, on in-stream nutrient storage and cycling. We predicted that supplemental, hatchery-raise...

Futile plasma membrane cycling of ammonium (NH4 ) is characteristic of low-affinity NH4 + transport, and has been proposed to be a critical factor in NH4 + toxicity. Using unidirectional flux analysis with the positronemitting tracer N in intact seedlings of barley (Hordeum vulgare L.), it is shown that rapid, futile NH4 + cycling is alleviated by elevated K supply, and that low-affinity NH4 + ...

A six-point primary sere developed on sand dunes and a four-point secondary sere developed on old fields were studied to examine the regulation of nitrification in succession. Soils from sites along the seres were incubated in funnel-microlysimeters leached weekly with NH4CI and other nutrient solutions. Nitrate output in soils from the five youngest sites along the primary sere was rapidly sti...

abstract in this study different proportions of nh4+ and no3- in the growth medium on plant growth were investigated in hydroponic greenhouse experiments. the objectives of these studies were to investigate if ammonium (nh4+) stress in cucumber, a species sensitive to nh4+ toxicity, can be alleviated by matching the nitrogen supply rate to the plant nitrogen demand. ammonium was applied at a re...

In comparison with the original determination based on Weissenberg film data [Khan et al. (1970 ▶). Acta Cryst. B26, 1889-1892], the current redetermination of diammonium hydrogenarsenate(V) reveals all atoms with anisotropic displacement parameters and all H atoms localized. This allowed an unambiguous assignment of the hydrogen-bonding pattern, which is similar to that of the isotypic phospha...

Futile plasma membrane cycling of ammonium (NH4+) is characteristic of low-affinity NH4+ transport, and has been proposed to be a critical factor in NH4+ toxicity. Using unidirectional flux analysis with the positron-emitting tracer 13N in intact seedlings of barley (Hordeum vulgare L.), it is shown that rapid, futile NH4+ cycling is alleviated by elevated K+ supply, and that low-affinity NH4+ ...

Plants can use ammonium (NH4+) as the sole nitrogen source, but at high NH4+ concentrations in the root medium, particularly in combination with a low availability of K+, plants suffer from NH4+ toxicity. To understand the role of K+ transporters and non-selective cation channels in K+/NH4+ interactions better, growth, NH4+ and K+ accumulation and the specific fluxes of NH4+, K+, and H+ were ex...

Solution culture experiments were carried out to study the kinetics at cotyledon stage (11-day-old) and the effect of different NO3/NH4 on NO3 and NH4 uptake at seedling stage (31-day-old) with two cultivars of sugar beet, including Tianyan7 and Tianyan8. NO3 uptake by sugar beet seedlings at cotyledon stage (11-day-old) reached equilibration after 2 hours of adaptation, and NH4 uptake reached ...