-The uptake of ammonium and nitrate in natural populations of marine phytoplankton is light dependent and often can be described adequately by the Michaelis-Menten equation. The halfsaturation constant for light intensity in nitrate and ammonium uptake is found to be from 1 to 14 ~o of surface light intensity, an intensity range occurring near the bottom of the euphotic zone. Since the uptake o...

Plant nutrients might affect the activity and bioavailability of heavy metals in the soil –plant environment thus their accumulation in the plant. Little is known about the effect of nitrogen fertilization on cadmium (Cd) uptake by alfalfa “Medicago sativa”. This work aims to characterize the oxidative status, the physiological stress parameters and the Cd uptake in alfalfa « Medicago sativa » ...

The utilization of amino acids for growth and their effects on nitrogen fixation differ greatly among the several strains of each species of Azospirillum spp. that were examined. A. brasiliense grew poorly or not at all on glutamate, aspartate, serine, or histidine as the sole nitrogen and carbon sources. Nitrogen fixation by most A. brasiliense strains was inhibited only slightly even by 10 mM...

The relative importance of phosphorus and nitrogen absorption fkom water and sediments by Egeria densa Planch. (Hydrocharitaceae), a subinerged macropliyte very common in Pampean streams in Argentina, was experiiiientally assesced. Two experiments were performed to determine the importance of water as opposed to sediment cource of phosphorus, and to investigate the effect oftype of nitrogenouc ...

abstractin order to investigate the effects of the inoculation with p. putida, r. leguminosarum bv. phaseoli and f. mosseae on yield and nutrient uptake of common bean (phaseolus vulgaris l.), a greenhouse experiment in a completely randomized factorial design with 3 treatment including a: microorganism in four level (no inoculation, p. putida, f. mosseae and mix inoculation of fungi and bacter...

introduction soil salinity is a major limiting factor in agricultural development within iran. nitrogen is the most important nutrient that its uptake is limited over other elements under saline conditions due to decrease in the permeability of plant roots, soil microbial activity and mineralization of organic compounds and nitrate uptake by high concentrations of chloride anions in the root zo...

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...