The role of the redox state of the apoplast in hormone responses, signaling cascades, and gene expression was studied in transgenic tobacco (Nicotiana tabacum) plants with modified cell wall-localized ascorbate oxidase (AO). High AO activity specifically decreased the ascorbic acid (AA) content of the apoplast and altered plant growth responses triggered by hormones. Auxin stimulated shoot grow...

The aim of the study was to monitor the effects of exogenous melatonin on cucumber (Cucumis sativus L.) chloroplasts and explore the mechanisms through which it mitigates chilling stress. Under chilling stress, chloroplast structure was seriously damaged as a result of over-accumulation of reactive oxygen species (ROS), as evidenced by the high levels of superoxide anion (O2-) and hydrogen pero...

The aim of the study was to induce B deficiency symptoms and to relate the generation of reactive oxygen species (ROS) and altered cellular redox environment with the effects of B deficiency in mulberry (Morus alba L.) cv. Kanva-2 plants. Study was undertaken on antioxidant responses, malondialdehyde (MDA) content as an indicator of oxidative damage and ratio of dehydroascorbate (DHA) to ascorb...

The influence of varied Mg supply (10-1000 micromolar) and light intensity (100-580 microeinsteins per square meter per second) on the concentrations of ascorbate (AsA) and nonprotein SH-compounds and the activities of superoxide dismutase (SOD; EC 1.15.11) and the H(2)O(2) scavenging enzymes, AsA peroxidase (EC 1.11.1.7), dehydroascorbate reductase (EC 1.8.5.1), and glutathione reductase (EC 1...

All aerobic biological systems, including N(2)-fixing root nodules, are subject to O(2) toxicity that results from the formation of reactive intermediates such as H(2)O(2) and free radicals of O(2). H(2)O(2) may be removed from root nodules in a series of enzymic reactions involving ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase. We confirm here the presence of thes...

The active compounds in the roots of Scutellaria baicalensis Georgi, a traditional Chinese medicinal plant, are mainly flavonoids which have anti-inflammatory, antitumour, and anti-HIV activity, respectively. The increasing annual average temperature has rendered the S. baicalensis plants grown in some ancient producing regions no longer suitable for their medicinal usage. Hydrogen peroxide pla...

The function of the apoplastic enzyme ascorbate oxidase (AO) was investigated in tobacco (Nicotiana tabacum). The abundance of AO mRNA was up-regulated by light. Cytosolic ascorbate peroxidase (APX1) transcripts were also highest in the light. In contrast, L-galactono-gamma-lactone dehydrogenase, stromal APX, and thylakoid APX transcripts remained constant over the day/night cycle. Salicylic ac...

To identify the genetic factors underlying the regulation of fruit vitamin C (L-ascorbic acid [AsA]) concentrations, quantitative trait loci (QTL) studies were carried out in an F1 progeny derived from a cross between the apple (Malus × domestica) cultivars Telamon and Braeburn over three years. QTL were identified for AsA, glutathione, total antioxidant activity in both flesh and skin tissues,...

Salt stress negatively affects many physiological processes in plants. Some of these effects may involve the oxidative damage of cellular components, which can be promoted by reactive oxygen species and prevented by antioxidants. The protective role of antioxidants was investigated in Lotus japonicus exposed to two salinization protocols: S1 (150 mM NaCl for 7 d) and S2 (50, 100 and 150 mM NaCl...

Brachypodium distachyon (Brachypodium) is a powerful model system for studying cereal, bioenergy, forage, and turf grasses. Nucleotide diversity (π) and linkage disequilibrium (LD) in candidate genes involved in the antioxidative pathways in this species are not known. The average π for CAT encoding catalase, GPX encoding glutathione peroxidase, DHAR encoding dehydroascorbate reductase, MDHAR e...