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Chlorophyll and Carotenoids: Pigments of Photosynthetic Bio-membranes

Methods in enzymology (Impact Factor: 2.09). 12/1987; 148C:350-382. DOI: 10.1016/0076-6879(87)48036-1
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    • "Pigments were extracted from 100 mg frozen plant material in 96% (v:v) ethanol and the absorbance of the ethanol extract was measured with a UV –visible spectrophotometer (Agilent 8453) at three wavelengths: 470, 648, and 664 nm. The amount of pigments (chlorophylls and carotenoids) was quantified according to the equations of Lichtenthaler (1987) "
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    • "Chlorophylls (Chl a and Chl b) and carotenoid contents were measured by light absorbance at 663, 644 and 452.5 nm by a spectrophotometer (Halo DB-20/ DB- 20S, Dynamica Company, London, UK) (Metzner et al., 1965). The concentrations of the pigments were calculated by using the adjusted extinction coefficients (Lichtenthaler, 1987). 2.3.2. "
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    ABSTRACT: The present study was aimed to evaluate the morphological, physiological and biochemical responses of Alternanthera Bettzickiana (Regel) G. Nicholson plant subjected to different levels of cadmium (Cd) and lead (Pb) (0, 0.5, 1.0 and 2.0 mM) stress. A. bettzickiana was able to accumulate Cd and Pb in different plant parts and total uptake of both metals was higher in shoots than roots. Plant growth, biomass and photosynthetic pigments increased with increasing metal concentrations, up to 1.0 mM, in soil and then decreased with higher metal levels. The activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) increased under lower metal levels (0.5 and 1.0 mM) while decreased at higher metal levels (2.0 mM). Leaf and root electrolyte leakage (EL), malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents decreased at lower metal levels (≤ 1.0 mM) while increased at higher levels. The present study clearly signifies the potential of A. bettzickiana plant towards Cd and Pb tolerance and accumulation especially at lower metal levels.
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    • "2.2. Methods Total chlorophylls (Chl aþb) and carotenoid contents (Car xþc) were estimated spectrophotometrically (UV/VIS 550, Unicam, UK) from pigment extracts in 80% acetone (Lichtenthaler, 1987 "
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    ABSTRACT: We examined the acclimation response of the photosynthetic apparatus of barley (Hordeum vulgare L.) to a combination of UV-A and UV-B radiation (UVAB) and to UV-B radiation alone. Our aim was to evaluate whether UV-A radiation prevents UV-B-induced damage to the photosynthetic apparatus and whether UV-A pre-acclimation is required to mitigate the negative influence of UV-B radiation. Barley plants were grown from seeds under low photosynthetically active radiation (50 μmol m(-2) s(-1)) either in the absence or presence of UV-A radiation (UVA- and UVA+ plants, respectively). After 8 days of development, plants were exposed simultaneously to UV-A and UV-B radiation for the next 6 days. Additionally, UVA- plants were exposed to UV-B radiation alone. The UVA+ plants had a higher CO2 assimilation rate near the light-saturation region (AN) and a higher content of both total chlorophylls (Chls) and total carotenoids than the UVA- plants. Chls content, AN, the potential quantum yield of photosystem II (PSII) photochemistry (FV/FM), the capacity of light-induced thermal energy dissipation and the efficiency of excitation energy transfer within PSII remained the same or even increased in both UVA+ and UVA- plants after UVAB treatment. On the contrary, exposure of UVA- plants to UV-B radiation itself led to a reduction in all these characteristics. We revealed that the presence of UV-A radiation during UVAB treatment not only mitigated but completely eliminated the negative effect of UV-B radiation on the functioning of the photosynthetic apparatus and that UV-A pre-acclimation was not crucial for development of this UV-A-induced resistance against UV-B irradiation. Copyright © 2015 Elsevier Masson SAS. All rights reserved.
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