scholarly journals In Vivo Nitrate Reduction in Relation to Nitrate Uptake, Nitrate Content, and in Vitro Nitrate Reductase Activity in Intact Barley Seedlings

1976 ◽  
Vol 57 (4) ◽  
pp. 519-522 ◽  
Author(s):  
Wongchan Chantarotwong ◽  
Ray C. Huffaker ◽  
Bruce L. Miller ◽  
Robert C. Granstedt
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Nitrate Reductase Activity ◽  
Nitrate Uptake ◽  
Reductase Activity ◽  
Nitrate Content

Effects of Glufosinate on Anion Uptake in Lemna gibba G 1

1989 ◽  
Vol 44 (1-2) ◽  
pp. 33-38 ◽  
Author(s):  
Gudrun D. Trogisch ◽  
Helmut Köcher ◽  
Wolfram R. Ullrich
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Nitrate Uptake ◽  
Dark Respiration ◽  
Reductase Activity ◽  
Lemna Gibba ◽  
Proton Cotransport ◽  
Chlorophyll Formation

Abstract The duckweed Lemna gibba G 1 was used as a model to study inhibitory sites with the herbicide and glutamate analogue glufosinate (PPT). Growth and chlorophyll formation were partly inhibited by 25 n-M, completely suppressed by 250 (im PPT. Photosynthesis showed partial inhibition within few hours, dark respiration ( 0 2 consumption) increased already within one hour. In the presence of 1 mM PPT in the light, the ammonium pool of Lemna increased to 600% within few hours, later to 1000%. The overall amino acid pool exhibited a slower increase to 300%, the nitrate pool only a slight increase, while total phosphate remained almost unchanged. In the dark all these effects were less pronounced than in the light. Nitrate, nitrite and phosphate uptake were partially inhibited by PPT, especially after 19 h PPT pretreatment. Nitrate reductase activity in vitro, after PPT treatment in vivo, showed an inhibition similar to that of nitrate uptake. Ammonium was not taken up but released under the same conditions. The data are explained by a combined effect of PPT, by inhibition of glutamine synthetase leading to accumulation of ammonium from photorespiration and proteolysis, by membrane depolarization and inhibition of anion/proton cotransport, by secondary uncoupling of phosphorylation, and by secondary inhibition of nitrate reductase activity.

scholarly journals Sources of reducing equivalents for nitrate reductase in Pisum arvense roots

2014 ◽  
Vol 53 (4) ◽  
pp. 499-505 ◽  
Author(s):  
Grażyna Kłobus
Keyword(s):  
Nitrate Reductase ◽  
Organic Acids ◽  
Nitrate Reduction ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Pisum Arvense ◽  
Reducing Equivalents

The sources of the nitrate reductase (E.C 1.6.6.1) reducing equivalents were searched for in roots of <em>Pisum arvense</em> by measuring <em>in vivo</em> and <em>in vitro</em> nitrate reductase activity. It was found that the NADH<sub>2</sub> utilised in the process of nitrate reduction in the roots of <em>P. arvense</em> may be formed by glycolysis as well as in processes of organic acids oxidation such as 2-oxoglutaric, succinic and malic acids.

Differential effects of ozone on in vivo nitrate reduction in soybean cultivars. I. Response to exogenous sugars

1978 ◽  
Vol 56 (13) ◽  
pp. 1540-1544 ◽  
Author(s):  
Albert C. Purvis
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Foliar Injury ◽  
Glycolytic Intermediates ◽  
Glycine Max L ◽  
Growth Chambers ◽  
Visible Foliar Injury

Two cultivars of soybeans (Glycine max (L.) Merr.) differing widely in their resistance to ozone were exposed to 0.5 μl/ℓ ozone for 2 h in growth chambers. In vivo nitrate reduction was depressed by more than 50% in the primary leaves of Dare, the ozone-sensitive cultivar, but was not significantly altered in Hood, the ozone-resistant cultivar. Sucrose, up to 1.5% (w/v), added to excised seedlings of the Dare cultivar during exposure to ozone eliminated the ozone depression of in vivo nitrate reductase activity and also reduced foliar injury. Addition of two glycolytic intermediates, glyceraldehyde-3-phosphate and fructose-1,6-diphosphate, to the infiltration medium recovered some in vivo nitrate reduction in treated Dare leaves. The levels of extractable nitrate reductase and glyceraldehyde-3-phosphate dehydrogenase in the primary leaves of both cultivars were unaltered by ozone fumigations. These observations led to the conclusion that ozone depression of in vivo nitrate reduction is not due to ozone inactivation of nitrate reductase or of the enzymes coupling nitrate reduction to glycolysis, but may be caused by an inadequate supply of photosynthetic sugars. It was also noted that ozone depression of in vivo nitrate reduction only occurred with treatments which subsequently caused the development of visible foliar injury.

Changes in Leaf Nitrate Reductase Activity In Vivo and In Vitro During Light-Dark Transitions

1999 ◽  
Vol 8 (1) ◽  
pp. 37-40 ◽  
Author(s):  
B. K. Salalkar ◽  
R. S. Shaikh ◽  
R. M. Naik ◽  
S. V. Munjal ◽  
B. B. Desai ◽  
...  
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Leaf Nitrate

scholarly journals Effect of lead on nitrate reductase activity and nitrate assimilation in pea leaves

2014 ◽  
Vol 57 (4) ◽  
pp. 457-463 ◽  
Author(s):  
S. K. Sinha ◽  
H. S. Srivastava ◽  
S. N. Mishra
Keyword(s):  
Enzyme Activity ◽  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Organic Nitrogen ◽  
Reductase Activity ◽  
Total Organic Nitrogen ◽  
Intact Leaf ◽  
Leaf Tissues

The effect of Pb on nitrate reductase activity, protein, total organic nitrogen and on the chlorophyll content in excised and intact leaf tissues of <em>Pisum sativum</em> was examine. Enzyme activity assayed in vitro or in vivo in the excised leaves showed marked increase at lower concentrations of Pb while being inhibited at higher concentrations. In intact leaf tissues, the enzyme activity (in vivo or in vitro) was unaffected at lower concentrations but was inhibited at higher concentrations of Pb. Chlorophyll, carotenoids (non-nitrogenous pigments), soluble protein and organic nitrogen contents remained almost unaffected at all concentrations of Pb tested. It seems that nitrate reductase has a different response towards Pb pollution in this species, which is more tolerant to heavy metal pollution, especially Pb.

RELATIONS BETWEEN NITRATE REDUCTASE ACTIVITY AND NITROGEN ACCUMULATION IN SOYBEANS

1976 ◽  
Vol 56 (2) ◽  
pp. 377-384 ◽  
Author(s):  
MIR HATAM ◽  
D. J. HUME
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Nitrate Uptake ◽  
Reductase Activity ◽  
N Uptake ◽  
Nitrogen Accumulation ◽  
Total N ◽  
Total Plant ◽  
Nr Activity

An in vivo assay for nitrate reductase (NR) activity was adapted to measure total NR activity in soybean [Glycine max (L.) Merr.] plants grown for a 29-day period indoors. Disappearance of nitrate from the nutrient solution, plant nitrate and total plant nitrogen (N) also were measured. Under the conditions of this experiment, nitrate reduction estimated from NR activities agreed closely with actual nitrate reduction. The same assay was used to measure leaf NR activities of field-grown soybeans throughout the 1971 growing season. Leaf NR activities accounted for 77 and 72% of the total N uptake in plants receiving 0 and 280 kg N as NH4NO3/ha, respectively. Measurements of nitrate and ammonium losses from soil under soybeans and under adjacent bare soil at three stages of plant development suggested that in plots receiving no fertilizer N, 86% of N uptake from the soil was in the form of nitrate. The NR activity of field-grown plants agreed well with total plant N derived from soil nitrates. Results indicated that leaf NR activities were proportional to nitrate uptake and might be used to determine amounts and seasonal patterns of nitrate uptake by soybean plants.

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