Ammonium nutrition often represents an important growth-limiting stress in plants. Some of the symptoms that plants present under ammonium nutrition have been associated with pH deregulation, in fact external medium pH control is known to improve plants ammonium tolerance. However, the way plant cell metabolism adjusts to these changes is not completely understood. Thus, in this work we focused...

The rate of transport of L-amino acids by Saccharomyces cerevisiae epsilon 1278b increased with time in response to nitrogen starvation. This increase could be prevented by the addition of ammonium sulfate or cycloheximide. A slow time-dependent loss of transport activity was observed when ammonium sulfate (or ammonium sulfate plus cycloheximide) was added to cells after 3 h of nitrogen starvat...

Glutamate (Glu) dehydrogenase (GDH) catalyses the reversible amination of 2-oxoglutarate for the synthesis of Glu using ammonium as a substrate. This enzyme preferentially occurs in the mitochondria of companion cells of a number of plant species grown on nitrate as the sole nitrogen source. For a better understanding of the controversial role of GDH either in ammonium assimilation or in the su...

Pollen represents an important nitrogen sink in flowers to ensure pollen viability. Since pollen cells are symplasmically isolated during maturation and germination, membrane transporters are required for nitrogen import across the pollen plasma membrane. This study describes the characterization of the ammonium transporter AtAMT1;4, a so far uncharacterized member of the Arabidopsis AMT1 famil...

abstract regarding to this issue that nitrogen is one of the main essential elements for plant that growth and efficiency of plant is related to it, and on the other hand most of the water and soil resources in iran are alkaline; in order to evaluation of the interactive effect of different concentrations of sodium bicarbonate and nitrogen form on snap bean in hydroponic system, this research w...

Chopped wheat straw, containing increasing amounts of added water was treated with a constant level of ammonia (3.3 percent of straw dry matter) as ammonium hydroxide, and stored for I to 60 days before determing in vitro dry matter digestibility (IVD MD), nitrogen content and fiber-bound nitrogen (ADF-N) versus free ammonia nitrogen (NH3N) of the treated sample. The overall improvement (e.g., ...

Experiments were designed to assess the uptake rates of 0.2, 1, and 5 mM ammonium by the scleractinian coral Stylophora pistillata maintained under different feeding regimes (highly fed, slightly fed, and starved) for 4–8 weeks. NH4 was used to follow the incorporation of nitrogen in the zooxanthellae or in the animal tissue and to calculate uptake rates. After 4 or 8 weeks, fed corals containe...

parsley has a very high nutritional value, containing a, b and c vitamins and mineral nutrients. in order to investigation of the effect of different nitrogen sources on parsley an experiment conducted in a factorial combination of three nitrogen forms (calcium nitrate, ammonium sulphate and urea) and four nitrogen levels (0, 100, 125, 150 kg ha-1) by using a factorial experiment based on rando...

The production of 2,4-diacetylphloroglucinol (DAPG) by the biocontrol agent Pseudomonas fluorescens Pf-5 was studied in nutrient-solution based media with varying nitrogen content. No production of DAPG was observed when organic nitrogen was omitted from the media, regardless of the inorganic nitrogen source used. Furthermore, a micromolar concentration range of organic nitrogen was insufficien...

When the fungus Gibberella fujikuroi ATCC 12616 was grown in fermentor cultures, both intracellular kaurene biosynthetic activities and extracellular GA(3) accumulation reached high levels when exogenous nitrogen was depleted in the culture. Similar patterns were exhibited by several nonrelated enzymatic activities, such as formamidase and urease, suggesting that all are subject to nitrogen reg...