Characterization of the antioxidant system during the vegetative development of pea plants

Abstract

The antioxidative system was studied during the development of pea plants. The reduced glutathione (GSH) content was higher in shoots than in roots, but a greater redox state of glutathione existed in roots compared with shoots, at least after 7 d of growth. The 3-d-old seedlings showed the highest content of oxidised ascorbate (DHA), which correlated with the ascorbate oxidase (AAO) activity. Also, the roots exhibited higher DHA content than shoots, correlated with their higher AAO activity. The activities of antioxidant enzymes were much higher in shoots than in roots. Ascorbate peroxidase (APX) activity decreased during the progression of growth in both shoots and roots, whereas peroxidase (POX) activity strongly increased in roots, reflecting a correlation between POX activity and the enhancement of growth. Catalase activity from shoots reached values nearly 3 or 4-fold higher than in roots. The monodehydroascorbate reductase (MDHAR) activity was higher in young seedlings than in more mature tissues, and in roots a decrease in MDHAR was noticed at the 11 th day. No dehydroascorbate reductase (DHAR) was detected in roots from the pea plants and DHAR values detected in seedlings and in shoots were much lower than those of MDHAR. In shoots, GR decreased with the progression of growth, whereas in roots an increase was seen on the 9 th and 11 th days. Finally, superoxide dismutase (SOD) activity increased in shoots during the progression of growth, but specific SOD activity was higher in roots than in shoots.

Ascorbate deficient semi-dwarf asfL1 mutant of Lathyrus sativus exhibits alterations in antioxidant defense

“…Low ASC content and concomitant rise of its oxidized form, DHA, resulted in low cellular redox state of ascorbate in the asfL-1 mutant, and the lowest value (0.095) was recorded in the root. However, Díaz-Vivancos et al (2010) observed positive correlation between shoot growth and the ASC content. Several reports suggested that the root was much less influenced by ascorbate deficiency, and the glutathione played more important role than the ascorbate in promoting signals that permitted cell cycle progression in actively-growing root tissues (Vernoux et al 2000, Maughan and.…”

Sodium nitroprusside modulates gene expression involved in glutathione synthesis in Zea mays leaves

“…Glutathione synthesis takes place in two ATP-dependent steps, through reactions catalysed by γ-glutamylcysteine synthetase (γ-ECS) and glutathione synthetase (GSH-S), the rate-limiting enzyme being (γ-ECS) (Arisi et al 1997, Noctor et al 1998). Changes in the GSH redox state as well as the regulation in ROS production could act as a signal stimulating plant growth (Díaz-Vivancos et al 2010). Analysis of the expression level of (γ-ECS) and GSH-S after treatment with sodium nitroprusside and S-nitrosoglutathione (GSNO), showed that γ-ecs and gshs genes are up regulated by NO treatment in Medicago truncatula roots (Innocenti et al 2007).…”

Oligogalacturonides stimulate antioxidant system in alfalfa roots

“…Different biological responses to OGA have been reported, and the particular response observed depends on the plant species, the bioassay, and the chemical structure of the OGA used. The first response observed after the addition of OGA is the production of reactive oxygen species (ROS), including superoxide (O 2˙⎯ ) and hydrogen peroxide (Low and Merida 1996), which are known to be involved in the plant defence, as well as in plant growth and developmental processes (Camejo et al 2007, Dunand et al 2007, Díaz-Vivancos et al 2010. This response, termed the oxidative burst, is an immediate and localized reaction and occurs within a few min of the addition of OGA to suspension-cultured soybean (Legendre et al 1993), tobacco (Binet et al 1998) and tomato (Stennis et al 1998) or alfalfa seedling (Camejo et al 2011).…”