Plant Tissue Test for Determination of Optimum Concentration and Uptake of Nitrogen at Different Growth Stages in Lowland Rice

2003 ◽  
Vol 34 (1-2) ◽  
pp. 259-270 ◽  
Author(s):  
N. K. Fageria
Keyword(s):  
Plant Tissue ◽  
Optimum Concentration ◽  
Lowland Rice ◽  
Growth Stages ◽  
Different Growth Stages ◽  
Tissue Test

scholarly journals Growth phase dependent hydrogen isotopic fractionation in alkenone-producing haptophytes

2009 ◽  
Vol 6 (8) ◽  
pp. 1681-1694 ◽  
Author(s):  
M. D. Wolhowe ◽  
F. G. Prahl ◽  
I. Probert ◽  
M. Maldonado
Keyword(s):  
Physiological Stress ◽  
Accurate Determination ◽  
Isotopic Fractionation ◽  
Emiliania Huxleyi ◽  
Growth Stages ◽  
Single Well ◽  
Potential Alternative ◽  
Temperature Records ◽  
Different Growth Stages

Abstract. Recent works have investigated use of the hydrogen isotopic composition of C37 alkenones (δDK37s, lipid biomarkers of certain haptophyte microalgae, as an independent paleosalinity proxy. We discuss herein the factors impeding the success of such an application and identify the potential alternative use of δDK37s measurements as a proxy for non-thermal, physiological stress impacts on the U37K' paleotemperature index. Batch-culture experiments with the haptophyte Emiliania huxleyi (CCMP 1742) were conducted to determine the magnitude and variability of the isotopic contrasts between individual C37 alkenones. Further experiments were conducted with Emiliania huxleyi (CCMP 1742) andGephyrocapsa oceanica (PZ3-1) to determine whether, and to what extent, δDK37s varies between the physiological extremes of nutrient-replete exponential growth and nutrient-depleted senescence. Emiliania huxleyi was observed to exhibit an isotopic contrast between di- and tri-unsaturated C37 alkenones (αK37:3-K37:2≈0.97) that is nearly identical to that reported recently by others for environmental samples. Furthermore, this contrast appears to be constant with growth stage. The consistency of the offset across different growth stages suggests that a single, well-defined value for αK37:3-K37:2 may exist and that its use in an isotope mass-balance will allow accurate determination of δD values for individual alkenones without having to rely on time- and labor-intensive chemical separations. The isotopic fractionation between growth medium and C37 alkenones was observed to increase dramatically upon the onset of nutrient-depletion-induced senescence, suggesting that δDK37s may serve as an objective tool for recognizing and potentially correcting, at least semi-quantitatively, for the effects of nutrient stress on U37K' temperature records.

A METHOD FOR THE DETERMINATION OF THE LIGNIN CONTENT OF FRESH PLANT TISSUE WITHOUT PRELIMINARY DRYING

1948 ◽  
Vol 26b (6) ◽  
pp. 468-471 ◽  
Author(s):  
W. A. DeLong ◽  
D. MacDougall
Keyword(s):  
Plant Tissue ◽  
Lignin Content ◽  
Standard Procedure ◽  
Growth Stages ◽  
Fresh Tissue ◽  
Modified Method ◽  
Saturated Water ◽  
Fresh Plant ◽  
Oat Straw

A method of determining the lignin content of fresh plant tissue without preliminary drying has been devised. Prior to the final lignin determination with 72% sulphuric acid, the tissue is cut up, extracted with ether saturated water in a Waring Blendor, refluxed with 1% hydrochloric acid, and finally extracted with ethanol–benzene. For comparison, determinations were carried out by the above method and the standard A.O.A.C. procedure on material that had been air-dried at room temperature. Both greenhouse and field grown oat plants cut at various growth stages were used in this study. The modified method gave lower lignin values than the standard procedure with young succulent tissue. This difference decreased as the age of the tissue increased, and the results by all methods were very similar with oat straw. That the modified procedure on fresh tissue removes more interfering nitrogenous material than the other methods used is indicated by the lower nitrogen content of the lignin isolated. The absolute methoxyl contents of the residues isolated from dried tissue were greater than of those isolated from fresh material (from the same source). This may have been due to the inclusion of more methoxyl-containing carbohydrates in the former residues.

scholarly journals Growth phase dependent hydrogen isotopic fractionation in alkenone-producing haptophytes

2009 ◽  
Vol 6 (2) ◽  
pp. 4165-4200 ◽  
Author(s):  
M. D. Wolhowe ◽  
F. G. Prahl ◽  
I. Probert ◽  
M. Maldonado
Keyword(s):  
Physiological Stress ◽  
Accurate Determination ◽  
Isotopic Fractionation ◽  
Emiliania Huxleyi ◽  
Growth Stages ◽  
Single Well ◽  
Potential Alternative ◽  
Different Growth Stages ◽  
Objective Tool

Abstract. Several recent works have investigated use of the hydrogen isotopic composition of C37 alkenones (δDK37s), lipid biomarkers of certain haptophyte microalgae, as an independent paleosalinity proxy. We discuss herein the factors impeding the success of such an application and identify the potential alternative use of δDK37s measurements as a proxy for non-thermal, physiological stress impacts on the U37K' paleotemperature index. Batch-culture experiments with the haptophyte Emiliania huxleyi (CCMP 1742) were conducted to determine the magnitude and variability of the isotopic contrasts between individual C37 alkenones, an analytical impediment to the use of δDK37s in any paleoceanographic context. Further experiments were conducted with Emiliania huxleyi (CCMP 1742) and Gephyrocapsa oceanica (PZ3-1) to determine whether, and to what extent, δDK37s varies between the physiological extremes of nutrient-replete exponential growth and nutrient-depleted senescence, the basis for our proposed use of the measurement as an indicator of stress. Emiliania huxleyi exhibited an isotopic contrast between di- and tri-unsaturated C37 alkenones (αK37:3−K37:2≈0.97) that is nearly identical to that reported recently by others for environmental samples. Furthermore, this contrast appears to be constant with growth stage. The consistency of the offset across different growth stages suggests that a single, well-defined value for αK37:3−K37:2 exists and that its use in an isotope mass-balance will allow accurate determination of δD values for individual alkenones without having to rely on time- and labor-intensive chemical separations. The isotopic fractionation between growth medium and C37 alkenones was observed to increase dramatically upon the onset of nutrient-depletion-induced senescence, suggesting that δDK37s may serve as an objective tool for recognizing and potentially correcting, at least semi-quantitatively, for the effects of nutrient stress on U37K'

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