Effects of cytokinins on antioxidant enzymes in in vitro grown shoots of Pelargonium hortorum L. H. Bayley

Abstract

A b s t r a c tThe aim of this study was to determine the influence of meta-topolin (mT) and 6-benzyl-aminopurine (BAP) on the hydrogen peroxide (H 2 O 2 ) level and antioxidant enzymes activities in relation to the shoot formation and senescence process in Pelargonium hortorum cultivars, which differ in their susceptibility to leaf yellowing under in vitro conditions.In an early senescing cultivar 'Grand Prix', the addition of an aromatic cytokinin mT to abscisic acid (ABA)-enriched Murashige and Skoog (MS) basal medium more efficiently inhibited leaf yellowing than BAP. In both genotypes, meta-topolin was also the most effective in shoot formation. It was found that Pelargonium species varying in their susceptibility to senescence differ in H 2 O 2 production and antioxidant enzymes activities. Generally, meta-topolin more effectively enhanced H 2 O 2 production and POD activity than BAP and control medium, but its effect depended on genotype. The highest H 2 O 2 production stimulated by mT was observed on day 5 of subculture in late senescing cv. 'Bergpalais'. In both geranium genotypes, superoxide dismutase (SOD) and catalase (CAT) levels were highest at the beginning of the subculture period, during the initiation of shoot formation. SOD showed the highest activity on day 5 of subculture on the medium without cytokinin and generally being higher in cv. 'Bergpalais' than in cv. 'Grand Prix'. CAT activity was positively regulated by both cytokinins. POD activity was most effectively enhanced by mT, but on different days of subculture -on the 2 nd day of subculture in cv. 'Bergpalais' and on the 22 nd day of subculture in cv. 'Grand Prix'. The enhanced activity of POD in the presence of mT, 4-fold higher than on control medium, at the end of subculture in P. hortorum 'Grand Prix' coincided with the inhibition of leaf senescence.

Growth and Acclimatization Response of Sunflower Plantlets Treated with Naphthyl Acetic Acid-Based Environment Friendly Plant Growth Promoters

“…The increased values indicated some kind of adjustment when plants were shifted into soil. Our results are in accordance with Alatar et al Similarly, Wojtania et al [35] studied the relationship between meta topolins (mT) and 6 benzyl amino purine (BAP) with anti-oxidative enzyme activities in Pelargonium hortorum cultivars, and found the highest level of SOD and CAT at the beginning of subculture and during initiation of shoot formation in both geranium genotypes. Niczyporuk et al [13] also observed that all auxins either natural or synthetic, stimulate an enzymatic and non-enzymatic antioxidants Table 3.…”

Morphological and Biochemical Responses to Gibberellic Acid in Magnolia × ‘Spectrum’ in Vitro

“…Plant hormones are known to be involved in antioxidant responses of many plants (Mýtinová et al, 2011). For example, an influence of exogenously applied cytokinin on catalase (CAT) and peroxidase (POD) activities has been observed in axillary multiplication of Pelargonium hortorum (Wojtania and Skrzypek, 2014), and adventitious shoot formation in Pinus strobus (Tang and Newton, 2005). So far there has been no information on the effect of GA 3 on antioxidant enzyme activities in relation to magnolia shoot formation.…”

In vitro Response of Bougainvillea Explants and their Antioxidant Enzymatic Activities Treated with Naphthyl Acetic Acid-Based Synthetic Plant Growth Promoters

“…Similarly, Agniseka at al. [23] found increased CAT and SOD production in in vitroraised shoots of Pelargonium hortorum when treated with different concentrations of TDZ. They also found a positive correlation between days of sub culturing and antioxidant enzyme production, but the increase was not linear.…”

“…ROS behave as the second messenger in their response in plant tissue growth, development, and regulation [22]. In plants, ROS production is controlled by various nonenzymatic antioxidants and enzymatic defense systems, which is partially performed by SOD that converts O 2 to H 2 O 2 and CAT that degrades H 2 O 2 [23]. Superoxide dismutase and catalase are efficient antioxidant enzymes and they are an integral factor in the whole enzymatic process because their combined action prevents cellular degradation caused by O 2 -, H 2 O 2 , and OH -1 [24].…”