the effect on sugar beets of water and nitrogen movement in the soil under different water conditions was assessed over two years (2000-1) at the khorasan agricultural research center. three water treatments (no water stress, continuous stress and primary stress) and three n amounts (80, 160 and 240 kg n/ha) were investigated. the amount of moisture depletion in the water treatments was 50%, 80...

carbon and nitrogen are the two elements that most affect plant organogenesis. in vitro, usually as part of the macronutrients. some anecdotal evidence from the literature suggests that the ammonium (nh4+) to nitrate (no3–) ratio may affect orchid organogenesis. in this study, to test this hypothesis, different nh4+: no3– ratios were tested on the development of protocorm-like bodies (plbs) of ...

Total pyridine nucleotide concentration of root tissue for young soybean (Glycine max var. Bansei) and sunflower (Helianthus annuus L. var. Mammoth Russian) plants is the same with either ammonium or nitrate, but nitrate results in an increased proportion of total oxidized plus reduced NADP (NADP[H]) seemingly at the expense of NAD. The activity of NADH- and NADPH-dependent forms of glutamic ac...

We determined the quantum requirements for growth (1/ϕμ ) and fatty acid (FA) biosynthesis (1/ϕFA ) in the marine diatom, Phaeodactylum tricornutum, grown in nutrient replete conditions with nitrate or ammonium as nitrogen sources, and under nitrogen limitation, achieved by transferring cells into nitrogen free medium or by inhibiting nitrate assimilation with tungstate. A treatment in which tu...

The niaD gene of the fungus Aspergillus nidulans encodes an assimilatory nitrate reductase and exogenous ammonium represses its expression. Under anoxic conditions, however, A. nidulans expressed niaD even in the presence of ammonium and used the gene product for dissimilatory nitrate reduction (ammonia fermentation). This transcription regulation mechanism under anaerobiosis is critical for th...

Posttranslational regulation of nitrate assimilation was studied in the cyanobacterium Synechocystis sp. strain PCC 6803. The ABC-type nitrate and nitrite bispecific transporter encoded by the nrtABCD genes was completely inhibited by ammonium as in Synechococcus elongatus strain PCC 7942. Nitrate reductase was insensitive to ammonium, while it is inhibited in the Synechococcus strain. Nitrite ...

In order to evaluate the effects of inoculants and chemical fertilizer on quantitative and qualitative yield, a bread wheat cultivar treated with Azotobacter, arbuscular mycorrhiza fungi (AMF) and nitrogen sources by using split plot on the basis of randomized complete block design with three replications in Fars Agricultural Research Station during 2007-2008. Main plots consisted of nitrogen f...

Unpublished studies in the files of the Pineapple Research Institute of Hawaii indicate that under present cultural conditions the .pineapp1e plant displays superior performance with a foliar applied combination of ammonium and nitrate nitrogen than with either form of nitrogen alone. The studies presented here were undertaken to evaluate ammonium nitrate as a nitrogen source under different so...

Transcriptional adaptation to nitrate-dependent anabolism by Paracoccus denitrificans PD1222 was studied. A total of 74 genes were induced in cells grown with nitrate as N-source compared with ammonium, including nasTSABGHC and ntrBC genes. The nasT and nasS genes were cotranscribed, although nasT was more strongly induced by nitrate than nasS The nasABGHC genes constituted a transcriptional un...