0305-7364/0 * For corre bcgn.grignon. There is still disagreement about whether crop growth rate or soil nitrate concentration control nitrogen absorption by crops under ®eld conditions. The in ̄uence of these factors on the control of N uptake rate was examined in the absence of water stress, using data on dry matter production, above-ground nitrogen accumulation and soil nitrate concentration ...

Uptake of poor nitrogen sources such as branched-chain amino acids is repressed in the presence of high-quality nitrogen sources such as NH4(+) and glutamate (Glu), which is called nitrogen catabolite repression. Amino acid auxotrophic mutants of the fission yeast Schizosaccharomyces pombe were unable to grow on minimal medium containing NH4Cl or Glu even when adequate amounts of required amino...

Seagrass ecosystems are expected to benefit from the global increase in CO(2) in the ocean because the photosynthetic rate of these plants may be C(i)-limited at the current CO(2) level. As well, it is expected that lower external pH will facilitate the nitrate uptake of seagrasses if nitrate is cotransported with H(+) across the membrane as in terrestrial plants. Here, we investigate the effec...

We quantified nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) content, use (nutrient amount for one growth year), retranslocation (nutrients recycled before foliage senescence), uptake (use minus retranslocation), volume production per unit of uptake and fertilizer-uptake efficiency (percent applied taken up) in a 2 x 2 (nutrient and water) factorial experiment repl...

In the present study, the research results concluded that yield attributes of scented rice under aerobic culture responded up to 150 kg/ha nitrogen with four equal splits of nitrogen at 1⁄4 basal + 1⁄4 at active tillering + 1⁄4 at panicle initiation and 1⁄4 at heading. Grain and straw yields obtained higher values with highest level of nitrogen i.e. 175 kg/ha comparable with 150 kg/ha. Grain qu...

among crop plants, corn (zea mays l.) need a great amount of nitrogen during its growth period. an increase in the efficiency of nitrogen application not only decrease environmental pollutions, but also it,s economical. this study was conducted to determine the effect of nitrogen fertilization management on the yield and nitrogen efficiency in corn during 2006-2009 at safi-abad dezful agricultu...

Estimating the additional amount of global photosynthetic arbon influx into terrestrial ecosystems (PG) becomes possible with a leaf-level factor (Y) developed by Luo & Mooney only when an increase in atmospheric CO2 concentration (Ca) is small. Applying the Y factor to study long-term stimulation of PG with a large increase in Ca needs understanding of adjustments in leaf properties, canopy st...

Organic nitrogen (N) uptake by plants has been recognized as a significant component of terrestrial N cycle. Several studies indicated that plants have the ability to switch their preference between inorganic and organic forms of N in diverse environments; however, research on plant community response in organic nitrogen uptake to warming and grazing is scarce. Here, we demonstrated that organi...