The effects of exogenously applied hydrogen peroxide on the antioxidant system of pea plants were investigated. Ten-day-old pea seedlings were sprayed with 2.5 mM H 2 O 2 and 24 h later with 0.2 mM PQ. Samples were taken 0, 2 and 5 h after the start of illumination. The protective effect of H 2 O 2 was evaluated by monitoring of parameters related to the damage caused by PQ. The treatment with PQ led to a severe leakage of electrolytes from leaf tissues. Malondialdehyde level increased in PQ treated plants, but remained unchanged in H 2 O 2 pretreated ones after 5 h of illumination. Increased catalase and glutathione-S-transferase activity was observed in pea plants treated with H 2 O 2 and PQ. Ascorbate peroxidase activity decreased significantly after paraquat application, but pre-treatment with H 2 O 2 prevented ascorbate peroxidase inhibition to some extent. Increased guaiacol peroxidase activity was detected after H 2 O 2 application. PQ application caused a drastic decline in the levels of thiol-group bearing compounds, reduced glutathione and ascorbate, while the quantity of oxidized glutathione and dehydroascorbate were increased. The results presented on changes in enzymatic and nonenzymatic antioxidants suggest that preliminary H 2 O 2 application to pea plants treated with PQ, alleviates the toxic effects of the herbicide.
The effects of copper and cadmium and the preparation Biomin (natural substance extracted from coal with a.i. humic acids) on the biometric parameters, some stress markers and enzymatic activities in leaves and roots of triticale plants were investigated. The functional carbon distribution in Biomin was analyzed by 13 C NMR. It was found that all treatments retarded the growth and fresh weight of the plants. Heavy metals enhanced the content of stress markers proline and malondialdehyde and the activities of guaiacol peroxidase, superoxide dismutase and glutathione-S-transferase. The opposite trend was observed after Biomin application. Catalase activity was not affected considerably by the treatments. The free thiol-containing compounds were increased only in the roots of cadmium-treated plants. Comparative analysis of the measured parameters suggested that Biomin possessed protective effect against heavy metal toxicity.
Field experiments were conducted with two winter wheat cultivars that were primed with 6-benzylaminopurine (6-BA) or kinetin at the concentration 10 mg/L twice during the grain filling stage. After priming, wheat physiological parameters were measured in the field, and the analysis of yield was performed after harvest. Harvested seeds were subjected to low temperature storage for 12 months at –18 °С simulating conservation conditions in genebanks. In field experiments, treated plants exhibited up to 14% higher productivity, higher fresh and dry weight, and chlorophyll content index of flag leaves. Priming significantly improved germination, seedling vigour and growth parameters. In 5-days-old seedlings developed from low temperature stored seeds of field primed plants, the average accumulation of malondialdehyde and H<sub>2</sub>O<sub>2</sub> was estimated 25% lower, which contributed to higher cell membrane stability. These results correlated positively with growth characteristics of 15-days-old seedlings. The stimulating action of cytokinin priming was more pronounced in the modern cv. Geya-1 compared to the older cv. Sadovo 772 and could be attributed to improved anti-aging mechanism connected with better protection against oxidative damage.
A natural substance extracted from coal with humic acids as its active ingredients, namely Biomin, was added to nutrient medium and applied to triticale roots 3 days prior to UV-B irradiation treatment. UV-B treatment increased malondialdehyde and anthocyanin contents and the activities of peroxidase and superoxide dismutase, while it decreased chlorophyll content, fresh weight, and shoot length. Catalase and total phenolics content did not change in UV-B-treated shoots. The pretreatment with Biomin showed favorable effects on growth, decreased the oxidative damage provoked by UV-B irradiation, increased the content of UV-B-absorbing compounds, and positively influenced enzymatic activities. The application of Biomin on triticale plants was beneficial for counteracting the UV-B-induced oxidative stress by increasing the content of nonenzymatic antioxidants and antioxidant enzyme activities involved in detoxification of reactive oxygen species.
Young pea plants grown as a water culture were sprayed with hydrogen peroxide and 24 h later were treated with the herbicide paraquat. The effects of paraquat and H 2 O 2 treatment were investigated on the endogenous concentrations of free proline, and free and conjugated putrescine, spermidine and spermine. Application of PQ increased the free proline and Put, and decreased conjugated and bound polyamines. The results clearly demonstrate the oxidative damages provoked by PQ application. Single treatment with H 2 O 2 provoked considerable decrease in the free fraction of the three PAs studied 2 h after light exposition, but caused an increase in their respective conjugated fractions. Data suggest that PA changes after H 2 O 2 treatment are due to conversion from free to conjugated form. Three hours later free PAs in H 2 O 2 treated-plants reached control levels; however the conjugated remained higher than the control. No alterations were detected in proline concentration after H 2 O 2 treatment. Pretreatment with Н 2 О 2 activated some component of the plant protection mechanisms by causing an alteration in free/conjugated PAs ratio in plants subsequently subjected to PQ treatment. Data concerning PA and proline concentrations in plants treated with both compounds supposed that H 2 O 2 shows a protective role against PQ and improves the plant tolerance to the oxidative stress generated by paraquat.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.