The purpose of this study was to assess whether a visual examination of H-1 spectroscopic images could correctly lateralize patients with intractable temporal lobe epilepsy. 20 patients with intractable temporal lobe epilepsy and 10 volunteers were included in this study. Spectroscopic images were analysed using a protocol based on visual inspection. Images of the metabolites N-acetyl aspartate (NAA), choline (Cho), creatine (Cr) and lactate were obtained from a transverse plane oriented along the sylvian fissure. Images from each individual were evaluated independently by six reviewers. Results of the lateralization procedure obtained from the visual examinations were compared with those obtained from quantitative analysis of the spectra and with those obtained by magnetic resonance imaging (MRI), positron emission tomography (PET), neuropsychological examinations, and electroencephalographic (EEG) recordings. NAA images were found to be the most effective, amongst metabolite images, in lateralizing the epileptogenic lobe. Using the site selected for resection as the definition of the correct lateralization, 70% of the patients who underwent temporal lobectomy were correctly lateralized by the majority of the examiners using the visual inspection protocol. Based on the results of this study it is concluded that visual examination of H-1 spectroscopic images is potentially valid in lateralizing patients with intractable temporal lobe seizures. Confidence in the visual interpretation increased as the difference in NAA signal intensity between the temporal lobes increased. The threshold above which the majority of the examiners correctly lateralized the patients was approximate to 15% in NAA signal loss in the ipsilateral lobe.

An oblique circular arc representation for wellbore trajecories, a geometric analysis termed the sectional method, is presented. This approach permits projected line segments to be functions of the dogleg angle and to be related to usually measured displacements between survey stations. The advantages of this analysis are: a solution for the dogleg angle and a method of survey interpretation, the sectional method; a procedure for exact interpolation of true vertical depth, azimuth, and inclination between survey stations; a basis of solution for a computer program which provides course correction information during a turn to a target. The program provides a solution summary for a course correction from various survey stations in a well to any planned target. As a result, an optimum course correction or "minimum plugback depth" can be quickly determined. Once the desired kickoff point is selected, the program provides an exact solution of true vertical depth, azimuth, inclination, and toolface angle for every 100 of correction course length. The latter result provides a dramatic improvement in existing technology because all measurements used to control the correction run are now based on a center of turn rather than the arbitrary reference used in the typical ouija board solution; and because the solution is exact, such variables as effective toolface angle can better be evaluated and precisely corrected resulting in the smoothest possible turn with minimum doglegs.

Gas chromatographic (GC) profiles of tobacco volatiles and analyses of reducing sugars and total alkaloids as well as subjective smoking evaluations were used to test different tobaccos for tobacco flavor and aroma. Twenty of the major peaks from the GC profiles and subjective smoking scores were analyzed by multiple linear regression. Seven compounds of 20 were included in the regression model that was significant with correlation coefficient R2 = 0.702. Total volatile data for the 20 peaks and the subjective scores were transformed to comparable scales and analyzed by linear regression. The regression model was significant with a low correlation coefficient of R2 = 0.300. This study agrees with previously published data that volatiles are positively correlated with tobacco flavor and that some specific volatile compounds might be used as references of tobacco quality.

A field experiment with flue-cured tobacco,Nicotiana tabacum L., was conducted to estimate the uptake and partitioning of nitrogen during maturation and senescence. On the 83rd day after transplanting (crop day 83), nitrate which had been leached from the plow layer was replaced with an equivalent amount of15N-labeled nitrate. Plants were harvested at crop day 83, 90, 96, 106, 113, and 127, and each of 11 plant parts was analyzed for nitrogen derived from the soil (NDS) and from the applied15N-labeled fertilizer (NDF). Equivalent quantities of NDF and NDS were taken up during the initial week after15N-fertilizer application; in the subsequent 5 weeks, ten times more NDS than NDF were taken up. It appears likely that the leached nitrate (NDS) accumulated below the hard pan where it became available to plants as their roots penetrated this layer via fractures originating from prior deep chiseling. Of the NDF taken up during the initial week, 20% was partitioned to the root and 42%, 24%, 14% respectively, to the upper, middle and bottom node positions (leaves plus stems). The partitioning reflected the respective growth rates of the tissues. Little change in partitioning was evident during the subsequent 5-week period, indicating that little remobilization of NDF from older to younger tissues occurred. In contrast, some remobilization of NDS was apparent between crop day 96 and 106 when the uptake of both NDF and NDS was negligible. During this period root growth was sustained by the apparent transfer of NDS from the root stump and from the adjacent lower leaf and stem tissues. These responses occurred in tobacco grown under higher nitrogen fertility levels than those usually considered optimal for the growth of flue-cured tobacco, but under conditions which are sometimes encountered.

The use of instrumental neutron activation analysis (INAA) in determining selected elements in biological materials has been reported by numerous authors. Some of these have detailed the use of INAA to determine an elemental analysis in tobaccos of various geographical origins. This paper describes the first use of INAA to measure the distribution of selected inorganic elements within the tobacco leaf at a single plant stalk position for one tobacco curing routine. Three replicate plots of a common bright tobacco cultivar were grown under normal cultural conditions characteristic for the bright variety. The tobacco leaves were sampled at selected positions in the leaf. The brigh tobacco was cured in a conventional flue-curing barn using standard practices. Immediately after collection, each individual sample was freeze-dried, crushed and sampled. The leaf midrib samples were prepared using a similar procedure. A subsample of about 100 mg was taken from each sample, sealed in a polyethylene bag, irradiated in a thermal neutron flux of 2×1017 n·m−2·s−1 in a pneumatic rabbit system, and subsequently counted to obtain the reported data. A standard reference material was used as a comparator to yield relative elemental concentrations for Ca, Mg, Mn, Na, K, Cl and Br. The data show that chlorine, potassium, sodium and calcium have definite concentration trends within the tobacco leaf. The data also show that some elements, e.g. Mn, were more uniformly distributed throughout the leaf.

Leaf carotenoids are important precursors of aroma and flavor constituents in tobacco, Nicotiana tabacum L. In an F2 population resulting from a cross of ‘Hicks’ ✕ ‘Coker 139’, five cycles of mass selection were practiced for high and low total carotenoid concentrations in cured leaf. All 10 selected cycle populations, the original F2 population, and parental cultivars were evaluated at two locations. The effectiveness of mass selection for changing total carotenoids, the divergence and asymmetry of responses between the high and low populations and the correlated changes in other characters were measured. Based on a linear concurrent regression model, response to divergent mass selection for total carotenoids was significant in both directions. Average change per cycle of selection for total carotenoids was 4 μg g‐1 for the high population, and —5.4 μg g‐1 for the low population. Progress in the two populations was symmetric with the high population possessing 41% more carotenoids than the low population after five cycles of selection. Important correlated responses in other constituents occurred as well. Total alkaloids were positively correlated with carotenoid changes, diverging 46% between the high and low populations. Total alkaloids were altered 0.17 and —0.13% per cycle for the high and low populations, respectively. Leaf yields and grade index were negatively related to direction of carotenoid selections and diverged at cycle five by 20 and 45%, respectively. The complexity of cured leaf quality determination in tobacco is apparent from this study. If carotenoid concentrations in cured leaf are to be used as an indirect selection criterion for altering aroma and flavor of tobacco, selection schemes to minimize correlated responses for other chemical constituents may be necessary.

The objectives of this investigation were to (i) estimate the range of variability present for the oat (Avena sativa L.) seedling characteristics, including shoot length and weight and root length, weight, and volume; and (ii) to determine how these characters vary among groups of cultivars representing different breeding eras.Fifty‐two cultivars were chosen to represent a wide range of genetic backgrounds and breeding eras. The cultivars were classified as belonging to one, or more, of the following categories: I—spring‐sown, II—fall‐sown, III—sources of crown rust resistance, IV—earliest introductions, V—early selections, VI—early hybrid selections, VII—intermediate hybrid selections, VIII—modern hybrid selections, IX—sources of straw strength, X—diploid, XI—dwarfs, and XII—very tall. Comparisons were made between cultivar categories.Ranges in cultivar means expressed as a percentage of the grand mean for the five characters were: shoot length, 101.9 % ; root length, 81.5%; root volume, 81.8%; shoot weight, 113.3%; and root weight, 75.0%. Simple correlations were relatively high among all characters, ranging from 0.48 for shoot length and root volume to 0.84 for root volume and root weight (determined over all 52 cultivar means).The spring‐sown genotypes gave consistently higher values for the five growth characters than did the fall‐sown genotypes. Lines that are sources of crown rust resistance were genetically inferior in their seedling growth responses. The effects of selection pressure (for other characters) during the time progression from the earliest introductions to the modern hybrid selections were pronounced. The most obvious trend was toward greater root development in the modern selections. Shoot lengths were slightly reduced over the time span.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTransformations of chemical constituents during flue-curing of Nicotiana tabacum L. 2. Metabolism of nitrogenous and related constituentsAumeed N. Amin, R. C. Long, and W. W. WeeksCite this: J. Agric. Food Chem. 1980, 28, 3, 656–660Publication Date (Print):May 1, 1980Publication History Published online1 May 2002Published inissue 1 May 1980https://pubs.acs.org/doi/10.1021/jf60229a024https://doi.org/10.1021/jf60229a024research-articleACS PublicationsRequest reuse permissionsArticle Views48Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Ultrastructural observations of extranuclear temperature-sensitive induced lethality in a mutant of Nicotiana tabacum L. have shown that chloroplasts in this mutant gradually degenerate in plants grown at reduced temperatures, while mitochondria remain intact (Nessler and Wernsman, 1979). To further elucidate the organellar site of temperature sensitivity in this same tobacco mutant, leaf chlorophyll content, rates of oxygen exchange and ribulose 1,5 bisphosphate carboxylase (RuBPCase) activities were examined in temperature sensitive and control genotypes at varying time intervals during 35 days exposure to lethal temperatures (13°C day/8°C night). Rates of photosynthetic oxygen evolution by leaf disks rapidly declined in mutant plants after one week at low temperatures and remained significantly lower than rates in controls. Total chlorophylls in both mutant and control plants gradually decreased with the increased time at reduced temperatures. This decrease in chlorophyll content of temperature sensitive plants was not sufficiently rapid to account for the sharp drop observed in photosynthetic rates and probably resulted from the disruption of chloroplast membranes. Mitochondrial function in mutant plants was apparently unaffected by prolonged exposure to lethal temperatures as evidenced by the almost constant rates of respiratory oxygen uptake seen throughout the experiment. RuBPCase activities on a leaf area basis were similar in mutant and control plants over the last four sampling dates (days 14–35); thus this enzyme does not appear to be the site of the temperature-sensitive lesion. The loss of chlorophylls, rapid decline in photosynthetic oxygen evolution and continued respiratory oxygen uptake reported here for mutant plants grown at lethal temperatures supports the concept that the chloroplast is the site of extranuclear temperature-sensitivity in this tobacco genotype.

Corn seedling xylem exudate has a pH of 5.30 +/- 0.05 due to the presence of 10 millimolar malate which has a pK(a) of 5.13. This concentration of malate tends to buffer the xylem fluid at this pH. Exogenous treatment of corn seedling roots with CaCl(2) caused a concentration-dependent decrease in the pH of the xylem fluid as well as a decrease in the volume of fluid secreted into the xylem. Exogenous 50 millimolar CaCl(2) decreased exudate volume to 8% of control within 0.5 hour. Nitrate and malate deposition into the xylem was prevented by pretreatment in 5 millimolar CaCl(2); nitrate deposition was resumed shortly after resumption of malate deposition. Fifty millimolar l-tartrate, an inhibitor of the Cl(-), malate-activated ATPase (in vitro) of the tonoplast, also decreased exudate volume as well as slightly lowering exudate pH. The osmolality of the exudate was found to be constant at 70 +/- 11 milliosmomoles per kilogram in all treatments. Dixon plots (log of exudation rate versus pH of exudate) indicated a pK(a) of 5.11 for the exudation process which is very close to the pK(a) of l-malate (5.13). In addition, a Dixon plot of the l-glutamine deposition (l-glutamine being the major form of reduced nitrogen in the exudate) versus pH also indicated a pK(a) near 5.15.The pH optimum for glutamine transport into the xylem was 5.5. Deposition of glutamine into the xylem may be regulated by the xylem pH (5.30 +/- 0.05) which in turn may be regulated by the presence of 10 millimolar malate. It is proposed that the transport of glutamine into the xylem may provide the driving force for the exudation process.

The objectives of these investigations was to utilize a seedling growth technique to (i) verify previous reports on growth responses of germinating seedlings to nutrient additives; (ii) determine how soon seedling growth sponses occur; (iii) measure differences in genotypic respouses.A preliminary test with two F2 oat populations (Arena sativa L.) and their respective parents (‘Firecracker’ and ‘Goodand’; Goodland and N.C. 55) verified earlier observations of increased shoot growth and reduced root growth by 10‐lay‐old seedlings grown with a modified halfstrength Hoagland's solution, as compared to a growth medium of distilled water. Parental means were different and within‐parent variability was exhibited.Shoot and root lengths and dry weights, plus root volume, were measured on 4‐ to 10‐lay‐old seedlings of four oat genotypes (‘Carolee’, ‘Salem’, N.C. 2469‐3, and Firecracker) grown in distilled water and in modified half‐strength Hoagland's solution. Responses to the nutrient solution were apparent for shoot length and weight, and generally occurred after 6 to 8 days, depending upon the genotype. Hoagland's solution resulted in increased shoot length and shoot weight but reduced root length. Root weight and volume did not respond to the nutrient solution.Genotypic differences were evident for all five characters. The dwarf llne, N.C. 2469‐3, developed both shoots and roots more slowly than any of the other genotypes. Firecracker developed shoots and roots most rapidly while Carolee and Salem developed them at intermediate rates. Genotype ✕ growth medium interactions were evident for shoot length and weight and for root volume. A method for determination of root volume using the displacement technique is presented.

Electron microscopy confirms previous light microscope observations that tobacco leaf trichomes are glandular and that there are two different types. Both the tall trichome (multicellular stalk, unicellular or multicellular head) and the short trichome (unicellular stalk; multicellular head) exhibit characteristics common to gland cells—a dense cytoplasm, numerous mitochondria, and little vacuolation. The tall trichome contains structurally well developed chloroplasts and an elaborate network of endoplasmic reticulum. The short trichome contains undifferentiated plastids and endoplasmic reticulum which parallels the nucleus and plasmalemma. Few dictyosomes are seen either in the short trichome or in the tall trichome. The short trichome appears to undergo structural changes concurrently with the appearance of secretory product within the cells. The most noticeable change is the formation of the extraplasmic space between the cell wall and the plasmalemma. Electron dense secretory product is observed between the plasmalemma and the cell wall and within the intercellular spaces.

AbstractGrowth of flue‐cured tobacco (Nicotiana tabacum L.), ‘NC2326,’ was studied under controlled conditions in the North Carolina State University Phytotron (Southeastern Plant Environment Laboratory) to determine the patterns of growth over a wide range of day/night temperatures. Day temperatures ranged from 18 to 34 C at 4‐C intervals; night temperatures ranged from 14 to 30 C at 4‐C intervals. The growth of seedlings from first leaf to transplant size (Experiment I) was determined weekly intervals under all possible day/night temperature combinations. Fresh weight, dry weight, and leaf number were affected to a greater extent by night than by day temperature. The minimum night temperature for growth lies between 18 and 22 C. The 34/30 treatment yielded maximum fresh and dry weights, while maximum leaf number occurred under the 34/26 treatment. Diurnal variation in temperature favored increased growth. During early stages of seedling growth fresh and dry weight accumulation exhibited a bimodal response to day temperature.The growth of plants from transplant size to appearance of the first flower (Experiment II) was studied under the following day/night temperatures: 34/30, 30/26, 26/22, 22/18, and 18/14. Whole‐plant fresh and dry weights, leaf fresh and dry weights, leaf number, and plant height increased with temperature to 30/26, but decreased slightly at 34/30. Days‐to‐flower decreased with temperature to 26/22 and then increased at higher temperatures.

AbstractNitrate leaches readily from sandy soils. To test the sensitivity of nitrate reductase (a substrate‐inducible enzyme) as an indicator of nitrate leaching and restoration, low, normal, and high N treatments were imposed on young tobacco (Nicotiana tabacum L.) plants grown on a Durham sandy loam soil (Typic hapludult). Subsequent treatments imposed were soil leaching with and without a later application of replacement fertilizer. Plants were sampled at frequent intervals to determine the rapidity of changes in tissue nitrate concentration and nitrate reductase activity. Tissue nitrate concentration decreased within 24 hours after leaching in all N treatments in 1968. Nitrate reductase activity was decreased in the low and normal N treatments. The addition of replacement fertilizer resulted in increased nitrate reductase activity in the low and normal N treatments within 24 hours.

AbstractThe trend toward mechanized planting or transplanting of tobacco necessitates that seedling establishment (germination and initial growth to the first leaf stage) occur rapidly, at a uniform rate, and at high percentage. The effect of nine day/night temperature combinations on seedling establishment of flue‐cured tobacco, Nicotiana tabacum L. ‘NC 2326,’ was studied under controlled conditions. Seeds were sown and germinated in temperature‐controlled greenhouses, and daily counts were made to determine the number of seedlings whose first leaf had emerged. Little difference in total seedling establishment (percentage) or in uniformity of rate (standard deviation of the mean days‐to‐establishment) was found between the 26/26, 26/22, 22/22, and 22/18 C day/night temperature treatments. The rates of seedling establishment (mean days‐to‐establishment) between most treatments were different. Day/night temperatures of 26/22 C resulted in the best overall response with respect to total, rate, and uniformity of rate of seedling establishment.