To elucidate how physiological and biochemical mechanisms of chilling stress are regulated by abscisic acid (ABA) pretreatment, pepper variety (cv. 'P70') seedlings were pretreated with 0.57 mM ABA for 72 h and then subjected to chilling stress at 10°/6°C (day/night). Chilling stress caused severe necrotic lesions on the leaves and increased malondialdehyde and H(2)O(2) levels. Activities of mo...

Marigold plants (Calendula officinalis Linn) var. ‘Plamen Plus’ were grown under field conditions during the 2009 season in Trebišov, Slovakia and in Sofia, Bulgaria. The antioxidant potential in Slovak marigold flowers was due to the content of glutathione and ascorbate, two peroxidases (glutathione peroxidase and guaiacol peroxidase) and monodehydroascorbate reductase. The antioxidant capacit...

An Escherichia coli expression system has been developed for pea cytosolic ascorbate peroxidase (APX). The enzyme was expressed as a fusion product with the E. coli maltose-binding protein for rapid, affinity chromatography purification. Recombinant ascorbate peroxidase (rAPX) was purified by tryptic digestion to separate the maltose-binding protein from rAPX followed by three chromatographic s...

AP is involved in the destruction of harmful H202. In soybean (Glycine m a x [LI Merr.) root nodules, AP initiates a sequence of coupled redox reactions (ascorbate-GSH pathway) that results in peroxide scavenging (Dalton et al., 1986). The ascorbate-GSH pathway occurs in other plant tissues and has been extensively studied in chloroplasts where photoreducing conditions lead to the production of...

Even under optimal conditions, many metabolic processes, including the chloroplastic, mitochondrial, and plasma membrane-linked electron transport systems of higher plants, produce active oxygen species (AOS). Furthermore, the imposition of biotic and abiotic stress conditions can give rise to excess concentrations of AOS, resulting in oxidative damage at the cellular level. Therefore, antioxid...

Salinity affects normal growth and development of plants depending on their capacity to overcome the induced stress. The present study was focused on the response and regulation of the antioxidant defence system in Brassica oleracea roots under short and long salt treatments. The function and the implications of hydrogen peroxide as a stressor or as a signalling molecule were also studied. Two ...

drought, withnegative impacts on plant growth and development, isa major abiotic stress. in order to decreasing drought stress injuries and recognizing red peppers tolerance physiology against drought stress in greenhouse conditions, an experiment with three levels of drought stress (irrigation at 100, 60 and 30% of field capacity) and four concentrations of 5-aminolevolinic acid ((ala; 0, 0.25...

Reversible nonphotochemical fluorescence quenching depends on thylakoid lumen acidification and violaxanthin de-epoxidation and is correlated with photoprotection of photosynthesis. The O2-dependent electron flow in the coupled Mehler-ascorbate peroxidase reaction (MP-reaction) mediates the electron flow necessary for lumen acidification and violaxanthin de-epoxidation in isolated, intact chlor...

fire blight, caused by the bacterium erwinia amylovora, is one of the most destructive diseases of plants in the rosaceae subfamily pomoideae. the objective of this study was to determine the level of resistance of 30 pear cultivars and describe the biochemical changes induced in some resistant and susceptible cultivars. the level of resistance was determined by the length of the fire blight le...