Studies on Tobacco Alkaloids. II. The Formation of Nicotine and Nornicotine in Tobacco Supplied with N<sup>15</sup>.

Tso, T. C.; Jeffrey, R. N.

doi:10.1104/pp.32.2.86

Cited by 38 publications

(28 citation statements)

References 10 publications

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“…This conclusion is based on nornicotine levels rising "at the expense of" nicotine levels in both green and cured leaf (3,4,21,23), and isotopic labeling studies (10,19). Other studies have indicated that nornicotine may be synthesized independently of nicotine (8,9,22). Putrescine was oxidized 40o as well as N-methylputrescine (15), and the enzymic oxidation product of putrescine is 4-aminobutanal, which after spontaneous cyclization to pyrroline might be utilized to synthesize nornicotine.…”

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confidence: 99%

Nicotine Biosynthetic Enzyme Activities in Nicotiana tabacum L. Genotypes with Different Alkaloid Levels

Saunders¹,

Bush²

1979

Plant Physiol.

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Young plants of five Nicotiana tabacum L. genotypes were examined for activity of nicotine biosynthetic enzymes. Genotypes near isogenic except at two loci each with two alleles controlling nicotine level were used in a comparison of the four homozygous allelic combinations producing high, high intermediate, low intermediate, and low nicotine levels in a 'Burley 21" background. Putrescine N-methyltransferase (EC 2.1.1.53) and quinolinic acid phosphoribosyltransferase (EC 2.4.2.19) activities in root tissue of these four genotypes were proportional to leaf nicotine level, whereas N-methylputrescine oxidase activity in root tissue differed in proportion and ranking. Quinolinic acid phosphoribosyltransferase activities in leaf tissue were lower than in roots, but no differences were found among the four genotypes. The homozygous recessive alleles at either locus affect levels of all three enzyme activities examined in roots. Each locus seems to be involved in regulation of nicotine metabolism, but whether directly as a regulatory locus or indirectly through the metabolic product of a structural locus is not known.No difference was observed between enzymic oxidation of putrescine and N-methylputrescine by leaf and root extracts of Burley 21 (a high nicotine, low nornicotine genotype) and a high nornicotine cultivar, "Robinson Medium Broadleaf." Putrescine was utilized as a substrate to a greater extent than N-methylputrescine by leaf extracts compared with root extracts of both cultivars. It was concluded that genetic differences in levels of nicotine and nornicotine were not due to differences in enzymic oxidation of these two precursors during alkaloid biosynthesis.Nicotine is the predominant alkaloid in commercial tobacco cultivars, where it is found in concentrations of 2 to 5% of dry weight. Nicotine level as influenced by cultural practices of nitrogen fertilization, plant decapitation, water regime, and axillary bud control has been reviewed recently (2). Low total alkaloid levels are associated with homozygous recessive alleles at both the A and B genetic loci, and intermediate alkaloid levels are found when the homozygous recessive alleles are present at only one of the two loci (I 1).Nicotine, composed of single pyridine and N-methylpyrrolidine rings linked together, is synthesized primarily in the root (1,5). Support for the role of ornithine decarboxylase putrescine Nmethyltransferase (EC 2.1

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confidence: 99%

Nicotine Biosynthetic Enzyme Activities in Nicotiana tabacum L. Genotypes with Different Alkaloid Levels

Saunders¹,

Bush²

1979

Plant Physiol.

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“…The Knowledge has accumulated as to the role of pectinase in plant disease (1,12,13,14). In this paper evidence will be presented that pectinase preparations can cause a respiratory acceleration and increase of the activities of polyphenol oxidase and peroxidase in host tissues.…”

Section: Resultsmentioning

confidence: 99%

“…The conversion of nicotine to norniicotine occurred only at a later stage of plant development (2,13 All the grafted plants with N. glaufca scion had no nicotine regardless of whether the grafted stock was nicotine type or nornicotine type. Three possible explanations are suggested as follows: A) The formation of anabasine in the N. glauica scion is at the expense of nicotine, although it had been demonstrated that anabasine was not formeed by rearrangement of the nicotine molecule (14); B) there is an active demethylation system in N. glauca scion in which nicotine was converted to nornicotine; and C) the pathway of nicotine formation was intercepted at the stage of nornicotine because of the absence of the specified methylation system in N. glauca scion.…”

Section: Resultsmentioning

confidence: 99%

“…Nornicotine is formed before nicotine in the root as well as the shoot of Nicotiana plants (11,13). In nicotine biosynthesis.…”

Section: Resultsmentioning

confidence: 99%

“…Results on alkaloid composition after leaf curing are also available, but are omitted from this report because little changes were observed in most cases except in Maryland Robinson in whiclh most of the nicotine was converted to nornicotine cluring curing (13).…”

Section: Methodsmentioning

confidence: 99%

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Influences of Stock and Scion on Alkaloid Synthesis and Transformation

Jeffrey

Tso

1964

Plant Physiol.

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It is desirable and necessary to reexamine the influences of stock andl scion oIn alkaloid synthesis and transformation using plants which behave differently witlh respect to alkaloid formation (4). Experiments were conducted in the greenhouse for 3 years in an attempt to separate the effects of root, or stock, from those of the top, or scioIn, on alkaloid synthesis and transformation. Some of the grafting combinations reported in this paper resenmbled those prepared previously by Dawson (2), but plants witlh various degrees of ability in alkaloid synthesis were included in this study. Materials and MethodsThe following plants were used in these experi- shadle at high moisture levels for several days after cutting as the conductive system throughl the graft was unable to carry the loadl of normal transpiration. The nitrogen supply of the planits was kept at a minimuml until the original roots of the scion were removed and was then raisedl to encourage alkaloid syntlhesis. Some of the excised tops were analyzed to providle an estimate of the alkaloid already present in the tops of alkaloid synthesizing species when they were cut loose from their own roots and left on a stock of a practically nonalkaloid-synthesizing plant like tomato.The plants were not decapitated, and were harvested after 9 to 11 weeks. Only the tops, including 1

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Assessment of trace element impacts on agricultural use of water from the Dan River following the Eden coal ash release

Hesterberg

Polizzotto

Crozier

et al. 2015

Integr Envir Assess & Manag

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Catastrophic events require rapid, scientifically sound decision making to mitigate impacts on human welfare and the environment. The objective of this study was to analyze potential impacts of coal ash-derived trace elements on agriculture following a 35,000-tonne release of coal ash into the Dan River at the Duke Energy Steam Station in Eden, North Carolina. We performed scenario calculations to assess the potential for excessive trace element loading to soils via irrigation and flooding with Dan River water, uptake of trace elements by crops, and livestock consumption of trace elements via drinking water. Concentrations of 13 trace elements measured in Dan River water samples within 4 km of the release site declined sharply after the release and were equivalent within 5 d to measurements taken upriver. Mass-balance calculations based on estimates of soil trace-element concentrations and the nominal river water concentrations indicated that irrigation or flooding with 25 cm of Dan River water would increase soil concentrations of all trace elements by less than 0.5%. Calculations of potential increases of trace elements in corn grain and silage, fescue, and tobacco leaves suggested that As, Cr, Se, Sr, and V were elements of most concern. Concentrations of trace elements measured in river water following the ash release never exceeded adopted standards for livestock drinking water. Based on our analyses, we present guidelines for safe usage of Dan River water to diminish negative impacts of trace elements on soils and crop production. In general, the approach we describe here may serve as a basis for rapid assessment of environmental and agricultural risks associated with any similar types of releases that arise in the future.

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Studies on Tobacco Alkaloids. II. The Formation of Nicotine and Nornicotine in Tobacco Supplied with N¹⁵.

Abstract: The preceding paper (11) Craig counterculrrent apparatus (2) was used. In the course of this development the separation of a mixture prepared from nicotine, nornicotine, and anabasine was investigated by means of this apparatus,

Cited by 38 publications

References 10 publications

Nicotine Biosynthetic Enzyme Activities in Nicotiana tabacum L. Genotypes with Different Alkaloid Levels

Nicotine Biosynthetic Enzyme Activities in Nicotiana tabacum L. Genotypes with Different Alkaloid Levels

Influences of Stock and Scion on Alkaloid Synthesis and Transformation

Assessment of trace element impacts on agricultural use of water from the Dan River following the Eden coal ash release

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Studies on Tobacco Alkaloids. II. The Formation of Nicotine and Nornicotine in Tobacco Supplied with N15.

Abstract: The preceding paper (11) Craig counterculrrent apparatus (2) was used. In the course of this development the separation of a mixture prepared from nicotine, nornicotine, and anabasine was investigated by means of this apparatus,

Cited by 38 publications

References 10 publications

Nicotine Biosynthetic Enzyme Activities in Nicotiana tabacum L. Genotypes with Different Alkaloid Levels

Nicotine Biosynthetic Enzyme Activities in Nicotiana tabacum L. Genotypes with Different Alkaloid Levels

Influences of Stock and Scion on Alkaloid Synthesis and Transformation

Assessment of trace element impacts on agricultural use of water from the Dan River following the Eden coal ash release

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Studies on Tobacco Alkaloids. II. The Formation of Nicotine and Nornicotine in Tobacco Supplied with N¹⁵.