Changes in Antioxidative Protection in Bean Cotyledons During Natural and Continuous Irradiation-Accelerated Senescence

Abstract

We employed continuous irradiation (CL) for induction of premature senescence caused by enhanced production of reactive oxygen species. As a model plant we used bean (Phaseolus vulgaris L. cv. Jantar) cotyledons because they have well defined and a quite short life span. Senescence of bean cotyledons induced by CL progressed more rapidly than natural senescence: the life span of CL cotyledons was 13 d compared to 16 d in controls (C). Chl content was significantly lower in 10-and 13-d-old CL plants than in C plants and the change with age was not statistically significant. Activities of all antioxidative enzymes declined either with senescence onset or during whole life span. Activity of antioxidative enzymes, except ascorbate peroxidase, was lower in CL plants compared to C plants. On the contrary, contents of non-enzymatic antioxidants β-carotene and ascorbate were higher in CL plants than in C plants. No significant difference, except in the youngest cotyledons, was observed in glutathione content.

Changes in activities of antioxidant enzymes during Chenopodium murale seed germination

“…Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) are considered to be the main protective enzymes, being engaged in the removal of free radicals and activated oxygen species (Blokhina et al 2003). These detoxifying enzymes also have important roles throughout plant ontogeny, from seed germination (Bailly 2004) to growth and development (Procházková andWilhelmová 2004, Synková et al 2006). In germinating sunflower seeds, CAT activity increased prior to radicle protrusion, the latter being concomitant with the elimination of H 2 O 2 (Bailly et al 2000).…”

Chloroplast pigments, proteins, lipid peroxidation and activities of antioxidative enzymes during maturation and senescence of leaves and reproductive organs of Cajanus cajan L.

“…It is a genetically controlled developmental process whose regulation depends on both endogenous and environmental factors (Gan and Amasino 1997;Nooden et al 1997;Yoshida 2003). The onset of senescence in the vegetative and reproductive organs is characterized by a decrease of the antioxidant metabolism and overproduction of ROS might be one of the basis of the process (Pastori and del Rio 1997b;Prochazkova and Wilhelmova 2004). Extensive studies have been carried out with detached systems in relation to senescence.…”

The capacity of antioxidant protection during modulated ageing of bean (Phaseolus vulgaris L.) cotyledons. 2. The low‐molecular weight antioxidants

“…We studied age-dependent changes in low molecular antioxidants, that is carotenoids, ascorbate and GSH during natural and modulated ageing of bean cotyledons. We have previously observed a decline in antioxidative enzyme systems in bean cotyledons 23 and in maize leaves, 24 with increasing age either aged naturally or under mild stress.…”