Antioxidant responses ofin vitroshoots ofDeschampsia antarcticato Polyethylene glycol treatment

Abstract

Abstract:To understand the adaptability to environmental stresses by Deschampsia antarctica, one of the two vascular plants growing in Antarctica, we analysed the activity of several antioxidant enzymes, including peroxidase (POD, EC 1.11.1.7), ascorbate peroxidase (APX, EC 1.11.1.11), catalase (CAT, EC 1.11.1.6)) and glutathion reductase (GR, EC 1.6.4.2), in shoots subjected to drought stress (PEG-8000, -0.3 MPa). Additionally, levels of total phenolic compounds, flavonoids and ascorbate, were determined. The content of malondialdehyde (MDA), chlorophyll and hydrogen peroxide did not change as a result of PEG-8000 treatment. In addition, treated plants showed higher enzymatic activity of CAT, POD and GR in shoots than control plants. In addition, a high capacity to scavenge free radicals was also detected in stressed plants. These results seem to indicate that in D. antarctica tolerance of drought stress is associated with enhanced activity of antioxidant enzymes and free radical scavenging capacity.

Oxidative Stress Studies in Plant Tissue Culture

“…CAT is also important in the removal of H2O2 generated in peroxisomes during the -oxidation of fatty acids, photorespiration, and purine catabolism (Ahmad et al, 2008;Gill and Tuteja, 2010;Karuppanapandian et al, 2011). Various abiotic stresses induced CAT activities under in vitro conditions in different plants, including hyperhydricity, salinity, drought, and gamma radiation (Saher et al, 2004;Chakrabarty et al, 2005;Rahnama and Ebrahimzadeh, 2005;Dewir et al, 2006Niknam et al, 2006Erturk et al, 2007;Dasgupta et al, 2008;Sivritepe et al, 2008;Shehab et al, 2010;Yang et al, 2010;Zamora et al, 2010;El-Beltagi et al, 2011;Sen and Alikamanoglu, 2011;Helaly and El-Hosieny, 2011;Patade et al, 2012) in contrast, Fe-deficiency stress reduced activity of CAT (Lombardi et al, 2003;Mohamed and Aly, 2004). CAT activities also induced in Medicago sative clones, which were improved with in vitro selection method, under PEG-treatment (Safarnejad, 2004).…”

“…POX prefers aromatic electron donors such as guaiacol and pyragallol to catalyze H2O2, and many researchers reported that excess POX activities were measured in a wide range of plant varieties under abiotic stress conditions induced with in vitro culture techniques (Saher et al, 2004;Chakrabarty et al, 2005;Rahnama and Ebrahimzadeh, 2005;Dewir et al, 2006;Niknam et al, 2006;Erturk et al, 2007;Dasgupta et al, 2008;Kumar et al, 2008;Sivritepe et al, 2008;Zamora et al, 2010;Sen and Alikamanoglu, 2011, ;Helaly and El-Hosieny, 2011). POX also decomposes indole-3-acetic acid (IAA) and has a role in the biosynthesis of lignin and defense against biotic stresses by consuming H2O2 in the cytosol, vacuole, and cell wall as well as in extracellular space (Gill and Tuteja, 2010;Karuppanapandian et al, 2011).…”

“…A further study by hyperhydration, Chakrabarty et al, (2005) reported that APX, MDHAR and GR activities increased but DHAR activity decreased in apple. In a wide range of plant species were observed increase in GR and APX activities under different abiotic stress conditions-induced with tissue culture (Israr et al, 2006;Erturk et al, 2007;Sivritepe et al, 2008;Shehab et al, 2010;Zamora et al, 2010;Helaly and El-Hosieny, 2011). Generally known that APX has a higher affinity for H2O2 (μM range) than CAT and POX (mM range) and it may have a more crucial role in the management of ROS during stress (Gill and Tuteja, 2010;Karuppanapandian et al, 2011).…”

Morphological and Ultrastructural Changes of Organelles in Leaf Mesophyll Cells of the Arctic and Antarctic Plants of Poaceae Family Under Cold Influence

“…Those structures preserve the integrity of chloroplast membranes under exposure to oxidative stress (Zamora et al, 2010). Clusters of small lipid plastoglobules were observed in the chloroplasts of disintegrating cells in the analyzed polar plants.…”

Preliminary data of antioxidant activity of green seaweeds (Ulvophyceae) from the Southwestern Atlantic and Antarctic Maritime islands

“…Recently, Zamora et al (2010) described high levels of antioxidant production enzymes in the shoots of Deschampsia antarctica Desvaux, an Antarctic vascular plant, subjected to drought stress. In addition, other studies have found strong antioxidant activity in Antarctic lichen species (Paudel et al, 2008;Luo et al, 2009) and filamentous fungi (Tosi et al, 2010).…”