5/19/2023 0 Comments Alterpod download![]() The catalytic activity of SPO is characterized by the following: (i) the oxidation of SCN − to OSCN − is more than 10 times faster at pH 5 than 8 ( Fig. , which is transformed into OSCN − via (SCN) 2 by reactions (4.11)–(4.13).Reaction (4.30) is based on the successive reduction of Compound I to Compound II by SCN − (as in reaction 4.27) and Compound II to SPO by SCN − (as in reaction 4.28)-producing two molecules of SCN mosseae inoculation obviously decreased APX activity ( Porcel et al., 2003), implying that AMs might offer avoidance mechanisms for AM plants. However, in root and nodule of drought-stressed soybean plants, G. fasciculatum significantly increased POD activities and also induced two extra POD isozyme bands in three Ziziphus species, which may be due to increased P uptake by mycorrhization and to AM colonization and arbuscules ( Mathur and Vyas, 1995 Wu and Zou, 2009). Electrophoretic studies revealed that inoculation with G. During drought stress and the re-watering, POD activity in shoots of Juniperus oxycedrus was significantly increased by inoculation with a mixture of G. etunicatum significantly enhanced G-POD and APX activities in soybean shoots and roots under salt stress ( Ghorbanli et al., 2004). mosseae markedly increased POD and APX activities in leaf and root of Lycopersicon esculentum plants subjected to salt stress ( Huang et al., 2010). versiforme has higher leaf G-POD activity and root APX activity, and under water stress conditions the infected seedlings also recorded with higher leaf G-POD and leaf and root APX activity ( Wu et al., 2006b). Under well-watered conditions the Poncirus trifoliata seedlings infected by G. claroideum significantly increased APX activities in shoots ( Alguacil et al., 2003). etunicatum showed higher POD activities in shoots, compared with the plants inoculated with the nonpretreated fungi ( Ghorbanli et al., 2004). Under salt stress, soybean plants inoculated with salt pretreated G. Many experiments showed that AMs could alter POD activities of host plants, to a certain degree. Under abiotic stress conditions, POD also functions to interrupt the cascades of uncontrolled ROS in some organelles ( Jiang and Zhang, 2001 Harinasut et al., 2003). According to the catalytic substrate characteristics, POD can be divided into guaiacol peroxidase (G-POD), ascorbate peroxidase (APX) and glutathione peroxidase (GPX), etc. POD also degrades H 2O 2 into water and oxygen ( Tian et al., 2001). POD can act as catalysts to facilitate a variety of biological processes, especially donating electrons to bind to other substances, such as ferrocyanide and ascorbate, to break them down into harmless components ( Li et al., 2008). Peroxidase is widespread in a variety of animals, plants and microorganisms and comprises bacteria peroxidase, fungi peroxidase and plant peroxidase. Elsayed Fathi Abd-Allah, in Oxidative Damage to Plants, 2014 15.4.2 Peroxidase (POD) They are chloroplastic enzymes, which scavenge H 2O 2 generated primarily through superoxide dismutase action ( Chaitanya et al., 2002). Peroxidase when coordinated with superoxide dismutase (SOD) appears to play an important role in the scavenging process ( Farooq et al., 2008). ![]() Soybean plants showed enhanced peroxidase activity under water deficit ( Zhang et al., 2006). Increased peroxidase activity was also reported previously in wheat genotypes by Shao et al., (2008). Increase in the activity of SOD, POX, and CAT under salinity on tolerant chickpea genotypes has been reported ( Rasool et al., 2013). Extensive research on oxidative stress has shown that adverse environmental conditions induce overproduction of reactive oxygen species (ROS) in plants, such as O 2 Similarly, increased peroxidase activity has also been observed in low temperature stressed wheat seedlings ( Zhao et al., 2008). Increased peroxidase activity has been reported in cucumber seedlings subjected to chilling stress ( Feng et al., 2003). Irrespective of the genotypes, Radix astragali plants showed enhanced peroxidase activity under water deficit ( Sankar et al., 2007a,b, 2008). Peroxidase (POX) helps in decreasing H 2O 2 content and cell peroxidation of membrane lipids by decreasing MDA content. Mirza Hasanuzzaman, in Oxidative Damage to Plants, 2014 11.4.1 Peroxidase
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