Antioxidant response to drought in red and white clover

Abstract

Antioxidant response to drought in red (Trifolium pratense L., cv. ''Start'') and white clover (Trifolium repens L, cv. ''Haifa'' and cv. ''Debut'') grown as soil cultures was evaluated in water-deprived and recovered plants. Drought provoked oxidative stress in leaves confirmed by the considerable changes in electrolyte leakage, malondialdehyde, hydrogen peroxides and proline contents. Immunoblot of D-1-pyrroline-5-carboxylate synthetase (P5CS), which catalyzes the first two steps in proline biosynthesis, revealed strong induction of the enzyme in red clover plants submitted to drought. Water-deprived white clover plants exhibited distinct P5CS profiles. This was related to different drought tolerance of the studied T. repens cultivars. Isoenzyme analyses of superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) demonstrated certain differences in antioxidant defence among the tested varieties. It was confirmed that MnSOD (in both T. repens and T pratense) and FeSOD (in T. repens) isoforms were the most affected by drought. The red clover cultivar ''Start'' exhibited the lowest FeSOD and POX activities which could contribute to its poor performance under water deprivation.

Impact of Salinity Stress on Proline Reaction, Peroxide Activity, and Antioxidant Enzymes in Maize (Zea mays L.)

“…The tolerance to salinity or water stress could be related to different genetically determined capacity of plants to cope with oxidative stress events [23]. Therefore, the identification of physiological and biochemical components of the antioxidative defense system, which have the potential to confer drought or salinity tolerance, could be essential for the characterization of stress-tolerant plant species [24]. Activities of both CAT and SOD showed dramatic increases in plants under moderate salt stress (150 mM NaCl) compared with control, similar to findings by Barakat [25].…”

Response of growth and antioxidant enzymes to osmotic stress in two different wheat (Triticum aestivum L.) cultivars seedlings

“…Peroxidases are widely distributed in plant tissues where they are involved in growth, development, and senescence processes of plants (Mittler 2002). In drought-tolerant plant species, POD activity was found to be sufficiently high to enable the plants to protect themselves against oxidative stress (Fazeli et al 2007, Vaseva et al 2012). Activity of one or more antioxidant enzymes generally increases in plants exposed to drought conditions, and this elevated activity correlates with increased drought tolerance (Srivalli et al 2003, Hojati et al 2011, Hassanpour et al 2012.…”

“…The antioxidant enzymes such as superoxide dismutase (SOD, EC 1.15.1.11), peroxidase (POD, EC 1.11.1.7) and catalase (CAT, EC 1.11.1.6) were considered as a defensive team, whose combined purpose is to protect cells from oxidative damage (Mittler 2002). It was accepted that SODs are localized in chloroplasts, mitochondria, peroxisomes and the cytosol; POD activities are distributed in vacuoles, the cell walls and the cytosol, whereas CAT enzymes are presented only in peroxisomes (Vaseva et al 2012). The drought-induced changes in activities of SOD, POD and CAT were detected in a large number of plant species, such as Oryza sativa (Srivalli et al 2003), Sesamum indicum (Fazeli et al 2007), Carthamus tinctorius (Hojati et al 2011), Mentha pulegium (Hassanpour et al 2012), and Trifolium pratense (Vaseva et al 2012).…”

“…It was accepted that SODs are localized in chloroplasts, mitochondria, peroxisomes and the cytosol; POD activities are distributed in vacuoles, the cell walls and the cytosol, whereas CAT enzymes are presented only in peroxisomes (Vaseva et al 2012). The drought-induced changes in activities of SOD, POD and CAT were detected in a large number of plant species, such as Oryza sativa (Srivalli et al 2003), Sesamum indicum (Fazeli et al 2007), Carthamus tinctorius (Hojati et al 2011), Mentha pulegium (Hassanpour et al 2012), and Trifolium pratense (Vaseva et al 2012). These findings suggest that the induction of ROS-scavenging enzymes, such as SOD, POD and CAT, is the most common mechanism of drought tolerance for detoxifying ROS synthesized.…”

Selection and Breeding of Suitable Crop Genotypes for Drought and Heat Periods in a Changing Climate: Which Morphological and Physiological Properties Should Be Considered?

“…Control of ROS accumulation and detoxification are key processes during abiotic stress phases, which play critical role for yield stability [10]. As ROS protection is common mechanism mobilized in many abiotic stresses including drought [126][127][128][129], heat [10,115,125,130,131] and their combination [122,132], ROS scavenging enzymes and compounds are good candidates for enhanced protection to multiple stress situations. Higher tolerance to drought and/or heat is associated with concerted up-regulation of key detoxifying enzymes in several crop species/varieties leading to better ROS protection along with stability of key metabolic processes like photosynthesis [132] and maintenance of the alternative mitochondrial respiration [123].…”