This study was conducted on two canola (Brassica napus) cultivars, Okapi a winter type and cold tolerant and Rgs003 a spring type and cold sensitive. Seedlings were grown in an environmentally controlled growth room with 16 h d-1 photoperiod at 22/16 °C (day/night, control). At the 4-leaf stage, half of pots were transferred to a cold growth room for 7 d at 10/3°C (day/night, cold treatment) an...

We have previously shown that stromal and thylakoid-bound ascorbate peroxidase (APX) isoenzymes of spinach chloroplasts arise from a common pre-mRNA by alternative splicing in the C-terminus of the isoenzymes [Ishikawa, Yoshimura, Tamoi, Takeda and Shigeoka (1997) Biochem. J. 328, 795-800]. To explore the production of mature, functional mRNA encoding chloroplast APX isoenzymes, reverse transcr...

Heavy metals are the cause of major abiotic stresses in plants and a principal contributor to environmental pollution in recent decades. This study investigated the effects of exogenous hydrogen sulfide on the ascorbate-glutathione cycle in the leaves of coriander seedlings under copper stress. Results showed that copper stress not only reduced APX and GR activities but also decreased leaf AsA,...

The use of soil additives such as selenium can positively influence the antioxidative system plants, making them more tolerant to abiotic stresses. aim this work was evaluate concentration sodium selenite or selenate applied substrate that causes improve in plant growth and enzyme activities sunflower plants. treatments were divided in: control (absence selenium); 0.2 mg L-1 selenate; 0.4 0.8 s...

We have studied the expression of antioxidant genes in response to near ambient conditions of O3, SO2, and ultraviolet B (UV-B) in Nicotiana plumbaginifolia L. The genes analyzed encode four different superoxide dismutases (SODs), three catalases (Cat1, Cat2, and Cat3), the cytosolic ascorbate peroxidase (cyt APx), and glutathione peroxidase (GPx). The experimental setup for each treatment was ...

The response of the antioxidant defense system of an intertidal macroalgae Corallina officinalis L. to different dosages of UV-B irradiation was investigated. Results showed that superoxide dimutase (SOD) and peroxidase (POX) increased and then maintained at a relatively stable level when subjected to UV-B irradiation. Catalase (CAT) activity under medium dosage of UV-B irradiation (Muv) and hi...

The parasitic protozoa Leishmania major produces a peroxidase (L. major peroxidase; LmP) that exhibits activities characteristic of both yeast cytochrome c peroxidase (CCP) and plant cytosolic ascorbate peroxidase (APX). One common feature is a key Trp residue, Trp(208) in LmP and Trp(191) in CCP, that is situated adjacent to the proximal His heme ligand in CCP, APX, and LmP. In CCP, Trp(191) f...

This study examines phenolic peroxidase (POX) in Rhizophora mangle L. leaves in order to assess its role in phenolic manipulation and H 2 O 2 scavenging. Sun-exposed and understorey leaves experiencing varying degrees of nutrient stress were analysed from an oligotrophic cay off the coast of Belize. POX activity was unaffected by growth environment, but increased throughout leaf development and...