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Aerobic rice offers an attractive alternative approach over transplanting system as it consumes less water with low labour expenses. Flag leaf of six rice cultivars, viz. PR 120, PR 115, PR 116, Feng Ai Zan, PAU 201 and Punjab Mehak 1 was analysed for antioxidant defence mechanism and polyamine catabolism under the aerobic and the transplanting conditions. Ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT), superoxide dismutase (SOD), diamine oxidase (DAO) and polyamine oxidase (PAO) activities increased gradually from tillering to anthesis stage and then declined towards maturity stage under both planting conditions. Apparently, contents of ascorbic acid, α-tocopherol, proline and polyamines (PAs) also revealed similar trend. The aerobic condition elevated activities of PAO, SOD as well as contents of PAs, lipid peroxide and H2O2 whereas the transplanting condition had higher levels of APX, GPX, CAT and total antioxidant activities and contents of ascorbate, α-tocopherol and proline. Cultivars Feng Ai Zan, PR 115 and PR 120 exhibited superior tolerance over other cultivars by accumulating higher contents of PAs with increasing levels of PAO and SOD activities under the aerobic condition. However, under the transplanting condition PR 116 and PAU 201 showed higher activities of antioxidative enzymes with decreasing contents of lipid peroxide and H2O2. We infer that under the aerobic condition, enhancement of PAs and PAO activity enabled rice cultivars to tolerate oxidative stress, while under the transplanting condition, antioxidative defence system with decreasing of lipid peroxide content was closely associated with the protection of flag leaf by maintaining membrane integrity. In crux, results indicated that H2O2 metabolic machinery was strongly up-regulated especially at the anthesis stage.

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. 1959 82 70 77 Ghamsari, L., Keyhani, E., Golkhoo, S. (2007) Kinetics properties of guaiacol peroxidase activity in

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. 37 636 642 Amako, A., Chen, K., Asada, K. (1994): Separate assays specific for ascorbate peroxidase and guaiacol peroxidase and for the

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of 4,6-di(tertbutyl)guaiacol, a phenolic lignin model compound, by laccase of Coriolus versicolor. FFBS Letters 236 , 309-311. Aromatic ring cleavage of 4,6-di(tertbutyl)guaiacol, a phenolic lignin model compound, by laccase

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Acta Biologica Hungarica
Authors:
Ivanka Fedina
,
Maya Velitchkova
,
Katya Georgieva
,
Dimitrina Nedeva
, and
H. Çakırlar

., Guruprasad, N. (1998) Modulation of guaiacol peroxidase inhibitor by UV-B in cucumber cotyledons. Plant Sci. 136 , 131–137. Guruprasad N. Modulation of guaiacol peroxidase inhibitor by

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Journal of Thermal Analysis and Calorimetry
Authors:
Teresa Sebio-Puñal
,
Salvador Naya
,
Jorge López-Beceiro
,
Javier Tarrío-Saavedra
, and
Ramón Artiaga

analyzed. Guaiacol was identified along some degradation steps in all cases. This aromatic compound cannot be originated from cellulose or hemicellulose and is a typical degradation product of lignin. It means that a part of the lignins remained with

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sodium acetate buffer (pH 4.5), 0.5 mL substrate solution (46 mM guaiacol), and 0.5 mL culture supernatant ( Singh et al., 1988 ). The activity of Mn-peroxidase (E.C.1.11.1.13) was assessed using a buffered guaiacol solution, 2 mM MnSO 4 , and 0.4 M H 2 O

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of catechol with dimethyl carbonate. Part II. Selective synthesis of guaiacol over alumina loaded with alkali hydroxide . Appl Catal A Gen 166 : 425 – 430 10.1016/S0926-860X(97)00288-3 . 21

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temperatures [ 4 , 5 ]. Another is that the flash pyrolysis of lignin produces syringols, guaiacols, and phenols at high temperatures and mainly simpler gases of H 2 O, CO, CO 2 , CH 4 , and CH 3 OH at both low and high temperatures [ 5 , 6 ]. One will even

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]. A major part of vanillin is synthetically produced from guaiacol or lignin, and thus, it has become accessible for a wide range of use [ 10 ]. Vanillin consists of a phenol ring with an aldehyde-, a methoxy- and a hydroxy-group at specific positions

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