Nitrate is one of the major sources of nitrogen for the growth of plants. It is taken up by plant roots and transported to the leaves where it is reduced to nitrite in the. The main objective of this research was to investigate stimulatory effects of sodium nitrate, potassium nitrate, ammonia and urea on the production/generation of the nitrate reductase mRNA in Triticum aestivum plants. The pl...

The nitrate reductase in the mature root extract of 3-day maize (Zea mays) seedlings was relatively labile in vitro. Insoluble polyvinylpyrrolidone used in the extraction medium produced only a slight increase in the stability of the enzyme. Mixing the mature root extract with that of the root tip promoted the inactivation of nitrate reductase in the latter. The inactivating factor in the matur...

Nitrate reductase activity and protein percentage of various tree parts of two Populus clones were determined in relation to nitrate ion activity. Nitrogen was supplied as NH(4)NO(3) in a nutriculture system. Wisconsin-5 had significantly greater nitrate reductase activity than Tristis No. 1. Protein percentages of leaf plastochron index 10 leaves (tenth leaf below first leaf lamina exceeding 2...

When tobacco is provided with a high nitrate supply, only a small amount of the nitrate taken up by the roots is immediately assimilated inside the roots, while the majority is transported to the leaves where it is reduced to ammonium. To elucidate the importance of root nitrate assimilation, tobacco plants have been engineered that showed no detectable nitrate reductase activity in the roots. ...

An enzymatic assay system for nitrate employing the membrane-bound nitrate reductase (EC 1.7.99.4) of E. coli is described. Contrary to previous enzymatic assay systems, the present method is a kinetic one, i.e. the substrate, nitrate, is assayed by measuring the reaction rate of the nitrate reductase-catalyzed reaction. Based on the observation that the nitrate reductase-catalyzed reaction obe...

A barley (Hordeum vulgare L.) mutant, nar1a (formerly Az12), deficient in NADH nitrate reductase activity is, nevertheless, capable of growth with nitrate as the sole nitrogen source. In an attempt to identify the mechanism(s) of nitrate reduction in the mutant, nitrate reductase from nar1a was characterized to determine whether the residual activity is due to a leaky mutation or to the presenc...

The role of phytochrome in the induction of nitrate reductase of etiolated field peas (Pisum arvense L.) was examined. Terminal bud nitrate concentration increased in darkness, and the increase correlated with induction of nitrate reductase following brief exposure of intact plants to red, blue, far red, and white lights. Brief light exposure of intact plants stimulated nitrate uptake and induc...

Nitrate reductase from mutant 305 o f Chlamydomonas reinhardii has been purified about 90-fold and biochemically characterized. The enzyme can use reduced flavins and viologens as electron donors to reduce nitrate but, unlike the nitrate reductase com plex from its parental wild strain, lacks NAD(P)H-nitrate reductase and NAD(P)H-cytochrom e c reductase activities, does not bind to Blue-Agarose...