chlorophyll-a and hexaconazole

Hexaconazole is one of the triazole complexes that are broadly used as systemic fungicides with non-traditional plant growth regulator properties. Hexaconazole-Cu complex (Hex-Cu) is a new triazole derivative, and the biological effect of Hex-Cu has been rarely studied. In this work, we investigated the functions of Hex-Cu in regulating growth and the response to salt stress in the seedlings of Triticum aestivum. Pretreated with 60μmolL(-1) Hex-Cu, the seedling plants got increased root/shoot ratio by 42.0%, and the contents of chlorophyll and soluble protein were also increased by 38.1% and 27.9%, respectively. Furthermore, Hex-Cu alleviated the growth inhibition caused by salt stress, enabled the seedlings to maintain a higher proline content and lower malondialdehyde accumulation. The functions of Hex-Cu in regulating the expression of proline synthetase (P5CS and P5CR) genes were investigated by quantitative real-time PCR (qPCR). Under 100mmolL(-1) NaCl stress, the expression of P5CS and P5CR in the seedlings by Hex-Cu pretreatment were significantly up-regulated. It attributed to the enhanced salt tolerance in plants.

Topics: Chlorophyll; Malondialdehyde; Proline; Salt Tolerance; Triazoles; Triticum

The present study aims to evaluate the comparative effects of methyl parathion and hexaconazole on genotoxicity, oxidative stress, antioxidative defence system and photosynthetic pigments in barley (Hordeum vulgare L. variety karan-16). The seeds were exposed with three different concentrations, i.e. 0.05, 0.1 and 0.5 % for 6 h after three pre-soaking durations 7, 17 and 27 h which represents G1, S and G2 phases of the cell cycle, respectively. Ethyl methane sulphonate, a well-known mutagenic agent and double distilled water, was used as positive and negative controls, respectively. The results indicate significant decrease in mitotic index with increasing concentrations of pesticides, and the extent was higher in methyl parathion. Chromosomal aberrations were found more frequent in methyl parathion than hexaconazole as compared to their respective controls. Treatment with the pesticides induced oxidative stress which was evident with higher contents of H2O2 and lipid peroxidation, and the increase was more prominent in methyl parathion. Contents of total phenolics were increased; however, soluble protein content showed a reverse trend. Among the enzymatic antioxidants, activities of superoxide dismutase and peroxidase were significantly up-regulated, and more increase was noticed in hexaconazole. Increments in total chlorophyll and carotenoid contents were observed up to 0.1 % but decreased at higher concentration (0.5 %), and the reductions were more prominent in methyl parathion than hexaconazole as compared to their respective controls. Methyl parathion treatment caused more damage in the plant cells of barley as compared to hexaconazole, which may be closely related to higher genotoxicity and oxidative stress.

Topics: Antioxidants; Cell Cycle; Chlorophyll; DNA Damage; Hordeum; Hydrogen Peroxide; Lipid Peroxidation; Methyl Parathion; Mutagenicity Tests; Mutagens; Oxidative Stress; Peroxidases; Pesticides; Photosynthesis; Superoxide Dismutase; Triazoles

Enantioselectivity in ecotoxicity of chiral pesticides in the aquatic environment has been a subject of growing interest. In this study, the toxicological impacts of hexaconazole enantiomers were investigated with freshwater algae Scenedesmus obliquus. After 96 h of exposure, the EC(50) values for rac-hexaconazole, (+)-hexaconazole, and (-)-hexaconazole were 0.178, 0.355, and 0.065 mg l(-1) , respectively. Therefore, the acute toxicities of hexaconazole enantiomers were enantioselective. In addition, the different toxic effects were evaluated when S. obliquus were exposed to 0.2, 0.5, and 1.0 mg l(-1) of rac-hexaconazole, (+)-hexaconazole, and (-)-hexaconazole during 96 h, respectively. The chlorophyll a and chlorophyll b contents of S. obliquus treated by (-)-hexaconazole were lower than those exposed to (+)-hexaconazole, whereas the malondialdehyde contents of S. obliquus treated by (-)-form were higher than those exposed to (+)-form at higher concentrations. In general, catalase activities were significantly upregulated by exposure to (-)-enantiomer than (+)-enantiomer at all three concentrations. However, superoxide dismutase activities exposed to (-)-hexaconazole were lower than that exposed to (+)-hexaconazole at 0.2 mg l(-1) and 0.5 mg l(-1) . On the basis of these data, the acute toxicity and toxic effects of hexaconazole against S. obliquus were enantioselective, and such enantiomeric differences must be taken into consideration in pesticide risk assessment.

Topics: Antioxidants; Biomarkers; Chlorophyll; Chlorophyll A; Chlorophyta; Ecotoxicology; Environmental Pollutants; Malondialdehyde; Oxidative Stress; Stereoisomerism; Time Factors; Triazoles

An investigation was conducted in Plectranthus forskholii by giving it different concentrations (10, 15, 20, 25, and 30 mg L(-1)) of hexaconazole, a fungicide cum plant-growth regulator, in order to find out its effects on growth, pigment composition, and antioxidant potential. The treatments were given as soil drenching on different growth stages. All the concentrations of hexaconazole used significantly decreased the stem length and leaf area, whereas side branches, fresh and dry matter content, photosynthetic pigments, and antioxidant potential were increased. The number of tubers, length and girth of tubers, fresh and dry weight of tubers and tuber pigments were found to be the highest at a 25 mg L(-1) concentration of hexaconazole. Hexaconazole application at 25 mg L(-1) concentration was found to be more effective than 10, 15, 20, 25, and 30 mg L(-1) in promoting fresh and dry weight of root tuber over 165 days after planting. The pigments like chlorophyll, carotenoid; anthocyanins, xanthophylls and antioxidants such as ascorbic acid, reduced glutathione and total phenol were significantly increased under hexaconazole treatment when compared to untreated control plants.

Topics: Anthocyanins; Antioxidants; Ascorbic Acid; Carotenoids; Chlorophyll; Coleus; Dose-Response Relationship, Drug; Phenol; Pigmentation; Pigments, Biological; Plant Leaves; Plant Roots; Triazoles; Xanthophylls