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Spectrophotometric Characteristics of Chlorophylls a and b and Their Phaeophytins in Ethanol

Department of Botany, University of Nijmegen, Nijmegen The Netherlands
Biochimica et Biophysica Acta (BBA) - Biophysics including Photosynthesis 11/1965; 109(2):448-453. DOI: 10.1016/0926-6585(65)90170-6

ABSTRACT The absorption spectra of chlorophylls a and b in 96% ethanol, and of pheophytins a and b in 80% ethanol-0.01 N hydrochloric acid have been determined in comparison with known absorption coefficients.

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    • "For chlorophyll determination, 100 mg FW of tobacco leaves were incubated in 5 ml of 96% ethanol at 50–60 • C for 1 h or until complete decolourization. Chlorophyll content was then analyzed spectrophotometrically at 654 nm on the ethanolic supernatant in a Hitachi U-2000 spectrophotometer, as described by Wintermans and De Mots (1965). 2.6. "
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    ABSTRACT: The response of tobacco (Nicotiana tabacum L.) wild type SR1 and catalase-deficient CAT1AS plants was evaluated after exposure to CdCl2. CAT1AS plants accumulated more Cd than SR1 plants, and this was associated with reduced growth, but higher chlorophyll content and cell viability. Despite catalase deficiency, CAT1AS plants did not accumulate more H2O2 than the wild line when exposed to Cd, probably due to the fact that CAT1AS plants counterbalanced their catalase deficiency by increasing the constitutive guaiacol peroxidase and ascorbate peroxidase activities and by reducing the basal NADPH oxidase-like enzyme activity. Both lines could activate their antioxidant system upon Cd stress, although the stress response pathways showed wide differences in the mineral and nitrogen metabolism, since the wild-type line had reduced nitrates and iron content, while CAT1AS maintained the same level of nitrates and Fe than that of non-treated plants, and responded with a significant increase in proline. The results showed that, unlike previous reports using other type of stress with the same line plants, catalase did not play a crucial role in protecting against Cd toxicity and CAT1AS plants, compared to SR1, were able to activate alternative defence mechanisms against Cd toxicity.
    Environmental and Experimental Botany 01/2015; 109. DOI:10.1016/j.envexpbot.2014.07.008 · 3.00 Impact Factor
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    • "To determine the soluble protein in these Tween-containing samples, we found the 2-D Quant Kit (GE Healthcare , Hatfi eld, Hertfordshire, UK) to be ideal, on account of its sensitivity and the incorporation of an acidprecipitation step, enabling removal of interfering solutes (including Tween 80) prior to protein-dependent color development. The homogenized samples taken prior to centrifugation for chlorophyll and starch determination were added immediately to ethanol (giving 90% [v/v] ethanol) and the chlorophyll content of the clarifi ed solution determined spectrophotometrically as described by Wintermans and De Mots ( 1965 ). The resulting insoluble, decolorized pellet could then be assayed sequentially for soluble carbohydrate then starch content, using anthrone – a reagent specifi c for soluble carbohydrate – by a modifi cation of the approach of Hansen and Møller ( 1975 ) in which the soluble carbohydrate was fi rst removed from the insoluble starch by repeated extraction/sedimentation fi rst using 80% (v/v) and then 50% (v/v) ethanol. "
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    ABSTRACT: During a study of the contribution of photosynthetic traits to biomass yield among 11 diverse species of willow, the light and CO2 dependence of photosynthesis were found to differ, with absolute rates at ambient and saturating CO2, together with maximum rates of Rubsico-limited and electron-transport-limited photosynthesis (Vcmax and J, respectively) varying by factors in excess of 2 between the extremes of performance. In spite of this, the ratio, J/Vcmax – indicative of the relative investment of resource into RuBP regeneration and RuBP carboxylation – was found to fall within a narrow range (1.9–2.5) for all genotypes over two successive years. Photosynthetic rate (μmol CO2 fixed m−2 sec−1) showed a strong, inverse correlation with total leaf area per plant. Photosynthetic capacity, expressed on a leaf area basis, showed a strong, positive correlation with yield among some of the species, but when expressed on a whole plant basis all species indicated a positive correlation with yield. Thus, both leaf area per plant and photosynthetic rate per unit leaf area contribute to this relationship. The abundance and kinetic characteristics of Rubisco play a pivotal role in determining photosynthetic rate per unit leaf area and so were determined for the chosen willow species, in parallel with Rubisco large subunit (LSU) gene sequencing. Significant differences in the rate constants for carboxylation and oxygenation as well as the affinity for CO2 were identified, and rationalized in terms of LSU sequence polymorphism. Those LSU sequences with isoleucine instead of methionine at residue 309 had up to 29% higher carboxylase rate constants. Furthermore, the A/Ci curves predicted from each distinct set of Rubisco kinetic parameters under otherwise identical conditions indicated substantial differences in photosynthetic performance. Thus, genetic traits relating specifically to Rubisco and by implication to photosynthetic performance were also identified.
    12/2014; 3(2). DOI:10.1002/fes3.47
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    • "Traditional measurements of Chl concentration have involved spectrophotometric measures of Chl in acetone (Arnon 1949) or ethanol (Wintermans and De Mots 1965). These measures of leaf Chl are direct (Gitelson et al. 2003) and accurate (Monje and Bugbee 1992), but involve a time-consuming extraction of Chl from destructively harvested leaves. "
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