Ecophysiological responses of Araucaria angustifolia
seedlings to different irradiance levels.

Brazilian pine (Araucaria angustifolia [Bert.] O.Ktze.) is an indigenous conifer of the southern region of South America, typically regarded as a sun-loving species. However, there is insufficient information on the species’ behaviour under different irradiances to characterise its plasticity to light. The purpose of this work was to measure some ecophysiological responses of Brazilian pine seedlings to three irradiance levels: 100, 45 and 10% full sunlight. Thirty seedlings were grown under each of the irradiance treatments and, after 5 months, growth parameters, leaf chlorophyll concentration and in vivo nitrate reductase activity, in both leaves and roots, were analysed. There was no increase in shoot biomass allocation in response to shading, in contrast to results from other experiments. Only low-light seedlings showed significant increase in specific leaf area, as well as in the ratio of height to shoot biomass. Chlorophyll content and the ratio of chlorophyll a to chlorophyll b did not vary among treatments. Nitrate reductase activity was detected only in roots and was reduced in the low-light treatment. An overall analysis of the results points to a normal growth of Brazilian pine seedlings at both high- and medium-light sites, at least in their initial stages of development.

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Effect of mycorrhiza and nitrate nutrition on nitrate reductase activity in Scots pine seedlings

Physiologia Plantarum ◽

10.1034/j.1399-3054.1991.810115.x ◽

1991 ◽

Vol 81 (1) ◽

pp. 89-94 ◽

Cited By ~ 2

Author(s):

Tytti Sarjala

Keyword(s):

Nitrate Reductase ◽

Scots Pine ◽

Nitrate Reductase Activity ◽

Reductase Activity ◽

Pine Seedlings

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Antagonism of chloride and nitrate inhibits nitrate reductase activity in chloride-stressed maize

Plant Growth Regulation ◽

10.1007/s10725-020-00685-2 ◽

2021 ◽

Author(s):

Xudong Zhang ◽

Bastian L. Franzisky ◽

Lars Eigner ◽

Christoph‐Martin Geilfus ◽

Christian Zörb

Keyword(s):

Zea Mays ◽

Polyethylene Glycol ◽

Nitrate Reductase ◽

Osmotic Stress ◽

Nitrate Reductase Activity ◽

Reductase Activity ◽

Shoot Biomass ◽

Lower Intensity ◽

Maize Variety ◽

Osmotic Balance

AbstractChloride (Cl−) is required for photosynthesis and regulates osmotic balance. However, excess Cl− application negatively interacts with nitrate ($${\mathrm{NO}}_{3}^{-}$$ NO 3 - ) uptake, although its effect on $${\mathrm{NO}}_{3}^{-}$$ NO 3 - metabolism remains unclear. The aim was to test whether Cl− stress disturbs nitrate reductase activity (NRA). A maize variety (Zea mays L. cv. LG 30215) was hydroponically cultured in a greenhouse under the following conditions: control (2 mM CaCl2), moderate Cl− (10 mM CaCl2), high Cl− (60 mM CaCl2). To substantiate the effect of Cl− stress further, an osmotic stress with lower intensity was induced by 60 g polyethylene glycol (PEG) 6000 L−1 + 2 mM CaCl2), which was 57% of the osmotic pressure being produced by 60 mM CaCl2. Results show that high Cl− and PEG-induced osmotic stress significantly reduced shoot biomass, stomatal conductance and transpiration rate, but NRA was only decreased by high Cl− stress. The interference of NRA in chloride-stressed maize is supposed to be primarily caused by the antagonistic uptake of Cl− and $${\mathrm{NO}}_{3}^{-}$$ NO 3 - .

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Effects of different nitrogen sources on growth, chlorophyll concentration, nitrate reductase activity and carbon and nitrogen distribution in Araucaria angustifolia

Brazilian Journal of Plant Physiology ◽

10.1590/s1677-04202008000400005 ◽

2008 ◽

Vol 20 (4) ◽

pp. 295-303 ◽

Cited By ~ 3

Author(s):

Mário L. Garbin ◽

Lúcia R. Dillenburg

Keyword(s):

Nitrate Reductase ◽

Tree Species ◽

Nitrate Reductase Activity ◽

Reductase Activity ◽

Temperate Climate ◽

Growth Media ◽

Araucaria Angustifolia ◽

Inorganic N ◽

N Source ◽

Young Leaves

The southern Brazilian highland plateau is a mosaic of two contrasting plant communities, Araucaria forests and grasslands, which differ in the relative abundances and spatial patterns of soil nitrate and ammonium. However, we still do not know the inorganic N preferences of one key species in this mosaic, Araucaria angustifolia, the dominant tree species in the Araucaria forests and an important tree species invading the adjacent grasslands. Growth responses measured in a greenhouse study demonstrated that the species prefers NH4+ over NO3- as an inorganic N source. When provided alone, NO3- induced N deficiency symptoms: increases in root: shoot ratio, root branching and leaf mass per area, thickening of the shoot apexes and decreased mass-based chlorophyll and N concentrations of the young leaves. Nitrate-based nutrition also affected the whole plant N and carbon (C) distribution: young leaves accumulated less N and showed a larger C:N ratio than mature leaves. The nitrate reductase activity (NRA) followed the pattern of root: shoot partitioning expected for temperate climate conifers (activity concentrated in roots). However, the presence of NRA even under sole NH4+ nutrition indicates that plants may show constitutive levels of the enzyme, or that low levels of NO3- (possibly formed by contamination of the growth media) can induce leaf NRA. We suggest that A. angustifolia has ammonium as a preferential inorganic N source, and that this preference may favor a more successful establishment in grassland than in forest areas.

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THE EFFECT OF PURIFIED AMOUNT OF TRITERPENE GLYCOSIDES AND THEIR ENRICHED EXTRACT FROM LEAVES OF SILPHIUM PERFOLIATUM L. ON THE GROWTH AND ACTIVITY OF NITRATE REDUCTASE OF WIN-TER WHEAT PLANTS

chemistry of plant raw material ◽

10.14258/jcprm.2019045482 ◽

2019 ◽

pp. 441-448 ◽

Cited By ~ 1

Author(s):

Eleonora Sergeyevna Davidyants

Keyword(s):

Nitrate Reductase ◽

Winter Wheat ◽

Seed Treatment ◽

Nitrate Reductase Activity ◽

Growth Parameters ◽

Reductase Activity ◽

Dry Weight ◽

Potassium Nitrate ◽

Triterpene Glycosides ◽

Nr Activity

The effect of seed treatment with solutions of a purified amount of triterpene glycosides (PATG) containing, as major components, oleanolic acid glycosides – sylphiosides B, C, E, G, and extract (E) enriched with sylphiosides, from Silphium perfoliatum L. (Asteraceae) leaves on growth parameters and nitrate reductase activity (NR, EC 1.6.6.1) of 7-day winter wheat plants (Tritium aestivum L.) was studied. It was shown that, seed treatment with PATG solutions in concentrations of 0.0005 and 0.001% and E in concentrations of 0.2 and 0.4% caused an increase in the length of roots, shoots, wet and dry weight of seedlings compared to the control. The stimulating effect of these concentrations of PATG and E on the total nitrate reductase activity of the roots and leaves of seedlings has been established, and an increase in the stimulating effect of preparations on the activity NR оf against the background of substrate activation of the enzyme potassium nitrate (KNO3) was observed. The greatest increase in the total NR activity of roots and leaves of winter wheat plants was observed when PATG acted at a concentration of 0.001% and E – at a concentration of 0.4%, which amounted respectively 122 and 116%, when adding 1 ml of 50 mM KNO3 solution into the growing medium of plants – 141 and 137% relative to the control. The stimulating effect of exogenous triterpene glycosides on NR activity has been established for the first time. The obtained data allow to theoretically substantiate the possibility of practical use of triterpene glycosides and preparations based on them for the regulation of growth and nitrogen metabolism of plants.

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Effect of NaCI and supplemental calcium on growth parameters and nitrate reductase activity in maize

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.2005.016 ◽

2011 ◽

Vol 74 (2) ◽

pp. 119-123 ◽

Cited By ~ 3

Author(s):

Elżbieta Sacała ◽

Agnieszka Biegun ◽

Anna Demczuk ◽

Edward Grzyś

Keyword(s):

Nitrate Reductase ◽

Nutrient Solution ◽

Nitrate Reductase Activity ◽

Growth Parameters ◽

Reductase Activity ◽

Dry Weight ◽

Growth Responses ◽

Positive Effects ◽

Maize Varieties

In this study, investigated were the effects of NaCl (60 mmol/dm-3) and NaCl supplemented with different salts (5 mmol/dm-3 CaCl2, CaSO4, CaCO3, KCl), on growth of two maize varieties (Cyrkon and Limko). After 7 days of cultivation in nutrient solution the growth response to salinity of both maize varieties was similar. NaCl led to a dramatic decrease in growth of plants (approx. 50% reduction in fresh and dry weight of root, and 70% reduction in fresh weight of shoot). Addition of extra Ca2+ or K+ to nutrient solution containing NaCl did not definitely improve the growth parameters of maize. However, among the tested salts, CaCl2 had a beneficial visual effect on maize seedlings. In other cases the plants showed noticeable symptoms of salt damage. In long term exposure to salinity (two weeks) growth of Cyrkon was more inhibited than Limko. Comparison of growth responses in short-term exposure to salinity (7 days) with long-term (14 days) showed that in Cyrkon variety the negative effects of NaCl were intensified and addition of CaCl2 to salinized solution had not positive effects on growth. On the contrary, in Limko variety, there was a significant improvement in growth (especially in root dry weight). This fact indicates that during longer exposure to salinity Limko was able to adapt to those conditions. Salinity caused a significant decrease in leaf nitrate reductase activity (60% and 30% reduction respectively in Limko and Cyrkon). Addition of CaCl2 to salinized nutrient solution resulted in greater enzyme inhibition in Cyrkon (50% decline in relation to plants grown under sole NaCl), and 30% increase in Limko. Inhibition of nitrate reductase activity did not cause a decrease in concentration of soluble protein in maize leaves.

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