The pea chloroplastic fructose-1,6-bisphosphatase (FBPase) antisense construct reduced the endogenous level of expression of the corresponding Arabidopsis thaliana gene. The reduction of foliar FBPase activity in the transformants T(2) and T(3) generation ranged from 20% to 42%, and correlated with lower levels of FBPase protein. FBPase antisense plants displayed different phenotypes with a cle...

We examined the influence of macronutrient (nitrate and phosphate) additions on Ni uptake by phytoplankton (Prorocentrum donghaiense and Skeletonema costatum) and its subsequent transfer to marine copepods (Calanus sinicus and Labidocera euchaeta). Ni uptake by phytoplankton after 24h of exposure was markedly dependent on nutrient conditions, with a higher nutrient quota facilitating Ni accumul...

Net ecosystem ammonification and nitrification rates were estimated in the inner and outer segments of the coastal upwelling system of the Ría de Vigo during September 1990 and 1991. A multiparameter inverse method was used, combining short-time-scale changes (2 to 4 d) in the distributions of salinity, temperature, ammonium, nitrite, nitrate and dissolved oxygen with freshwater and heat budget...

Beaver-created ponds and dams, on the rise in the northeastern United States, reshape headwater stream networks from extensive, free-flowing reaches to complexes of ponds, wetlands, and connecting streams. We examined seasonal and annual rates of nitrate transformations in three beaver ponds in Rhode Island under enriched nitrate-nitrogen (N) conditions through the use of N mass balance techniq...

Both the bene®cial and the adverse effects of nickel supplement on the N assimilation and growth of tomato plants were evaluated while either urea or nitrate was applied as the sole N source in the nutrient solution. The nickel concentration in the plant was related to that in the solution. Urea toxicity to the plants was reduced by the nickel supplement at 0.01 mg lÿ1, and no symptom of urea t...

Biogeochemical processes controlling nitrate attenuation in aquifers are critically reviewed. An understanding of the fate of nitrate in groundwater is vital for managing risks associated with nitrate pollution, and to safeguard groundwater supplies and groundwater-dependent surface waters. Denitrification is focused upon as the dominant nitrate attenuation process in groundwater. As denitrifyi...