response of tea plants to b deficiency was studied in hydroponic medium under environmentally controlled conditions. plants height, number of leaves and dry matter production of shoot and root were significantly decreased by b deficiency. concentration of chlorophyll, carotenoids, anthocyanins and flavonoids was not affected by b deficiency in the young leaf, while a significant reduction of ch...

Two maize hybrids were grown under growth chamber conditions on solution or vermiculite medium that contained 2.5, 7.5, or 15 millimolar nitrate. The objectives were to determine: (a) the effect of nitrate supply on N metabolism and growth and (b) the interrelationship between nitrate uptake, flux, and reduction on the accumulation of reduced N and nitrate by the various plant parts and for the...

Neurospora ctassa (5297a) NADPH-nitrate reductase (NADPH:nitrate oxidoreductase, EC 1.6.6.2), a soluble, sulfhydryl-containing protein with FAD, a cytochrome b designated cytochrome bsm (N. crassa), and molybdenum as prosthetic groups, has been purified 500-fold by procedures including pH adjustment, ammonium sulfate fractionation of the resultant supernatant solution, phase separation to remov...

A NADH-nitrate reductase inhibitor has been isolated from young soybean (Glycine max L. Merr. Var. Amsoy) leaves that had been in the dark for 54 hours. The presence of the inhibitor was first suggested by the absence of nitrate reductase activity in the homogenate until the inhibitor was removed by diethylaminoethyl (DEAE)-cellulose chromatography. The inhibitor inactivated the enzyme in homog...

The standard procedure for the in ritro extraction of nitrate reductase from the tip region (0-2 cm) of the primary root of the maize (Zea mays L.) seedling indicated an activity of the enzyme approximately 5-fold higher than that obtained with an in vivo assay. In more mature regions of the primary root the ratio of in vitro to in vivo activity was much lower and in older seedlings was less th...

Detached first leaves of 3-day-old corn seedlings (Zea mays L. W64AxW183E) were incubated with nitrate in air or 100% O(2) in the light. Nitrate accumulation in the leaves was not depressed by O(2). NADH:nitrate reductase activity and enzyme protein, as measured with an enzyme-linked immunosorbent assay, increased in parallel during the 8 h nitrate treatment in air, but in O(2) the levels of en...

Mutants H-14 and H-18 of Staphylococcus aureus require hemin for growth on glycerol and other nonfermentable substrates. H-14 also responds to delta-aminolevulinate. Heme-deficient cells grown in the presence of nitrate do not have lactate-nitrate reductase activity but gain this activity when incubated with hemin in buffer and glucose. Lactate-nitrate reductase activity is also restored to the...

The addition of nitrite, the product of the reaction catalysed by nitrate reductase, to cell suspensions of the yeast Hansenula anomala caused a reversible inactivation of NADPH-dependent nitrate reductase activity. The haem- and Mo-dependent and Mo-dependent activities of nitrate reductase, determined with the non-physiological electron donors FMNH2 and reduced methyl viologen respectively, we...

In vitro formation of reduced nicotinamide adenine dinucleotide phosphate (NADPH)-nitrate reductase (NADPH: nitrate oxido-reductase, EC 1.6.6.2) has been attained by using extracts of the nitrate reductase mutant of Neurospora crassa, nit-1, and extracts of either photosynthetically or heterotrophically grown Rhodospirillum rubrum, which contribute the constitutive component. The in vitro forma...

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. ...