Responses of Non-Enzymatic Antioxidant Potentials in Radish by Triazole Compounds

Transcription

1 Global Journal of Molecular Sciences 4 (2): 63-67, 29 ISSN IDOSI Publications, 29 Responses of Non-Enzymatic Antioxidant Potentials in Radish by Triazole Compounds R. Sridharan, P. Manivannan, P.V. Murali, R. Somasundaram and R. Panneerselvam Stress Physiology Lab, Department of Botany, Annamalai University, Annamalainagar 68 2, Tamil Nadu, India Abstract: A study was undertaken to estimate the effect of triazole viz. triadimefon and hexaconazole on the l- non-enzymatic antioxidant potential of radish (Raphanus sativus L.). Triadimefon (TDM) mg and hexaconazole (HEX) 5 mgl who treated to per plant in one pot, on 8, 23,38 and 53 days after sowing (DAS). The non-enzymatic antioxidant contents like ascorbic acid (AA), reduced glutathione (GSH) and -tocopherol ( -toc) (RBF) were extracted and assayed on 3 and 6 DAS form shoot and tuber of both control and triazole treated plants. Triazole treatment increased the non-enzymatic antioxidants on the plant Raphanus sativus. Key words: Triazole Antioxidant Raphanus sativus INTRODUCTION Two main classes of plant defenses against oxidatative stress can be classified as non-enzymatic and Free radical is a chemical species with an unpaired enzymatic systems. The first class (non-enzymatic) electron that can be neutral, positive or negatively consists of small molecules such as ascorbic acid, charged. Although there alone four common oxygen glutathione, -tocopherol, reduced glutathione and metabolites in biologic system of free radicals and they riboflavin which can react directly with the reactive -2 are (i) superoxide anion (O ), (ii) hydrogen peroxide oxygen species, second class (enzymatic) defenses (H2O 2), (iii) hydroxyl radical (OH) and (iv) single oxygen have the capacity to elimate superoxides by the enzymes (O 2) []. These free radicals can be formed via enzymatic superoxide dismutase, ascorbate peroxidase, peroxidase reactions from non-autooxidiable substances such as and catalase [5-7] some non-enzymatic and enzymic halo alkanes, phenols, nitro compounds and aromatic antioxidant defenses include enzymes capable of amines [2]. Free radicals one also formed when cell removing, neutralizing or scavenging free radicals and constituents are exposed to ionizing radiation [3]. In oxyintermediates. Without there defenses, plants higher plants dissipation of excess photochemical could not efficiently convent solar energy to chemical energy is an immediate and finely turned response energy [9,]. which occurs through heat irradiation, alternate sinks Triazole compounds affected the activities of several for photosynthetic elements and down regulation to enzymes, especially those related to detoxification of photo system II [4-7]. The photo reduction of oxygen is active oxygen species and antioxidant metabolism [-3]. an important alternative sink for the consumption of They also protect plants from biotic and abiotic stresses excess energy but is associate with an increase in the including fungal pathogen, drought, salinity, air generation of reactive oxygen intermediates such as pollutions and low and high temperature [2-5] and also hydrogen peroxide (H2O 2) superoxide anion (O 2) hydroxyl it affect the isoprenoid pathway and alter the level of radical (OH) and oxygen (O 2) [8-] superoxide anion can certain plant hormones by inhibiting gibberellin synthesis, also be formed during the conditions of photo inhibition reducing ethylene evolution and increasing cytokinin, whereby an electron from photo system I is accepted kinetin levels some of the previous works carried out in by dioxygen, producing superoxide [4-9]. Stress our lab revealed the morphological and physiologic condition also results in an elevated rate of single electron changes associated with triazole treatment in various transport chain to molecular oxygen resulting in the plants, include inhibition of plant growth, increased formation of superoxide radicals and consequential chlorophyll levels, enlarged chloroplasts, thicker leaf hydrogen peroxide and hydroxyl radical production [7-]. tissue, increased root to shoot ratio and increased the Corresponding Author: Dr. R. Panneerselvam, Department of Botany, Annamalai University, Annamalainagar 68 2, Tamil Nadu, India 63

2 antioxidant potentials [-7]. Therefore, there is a -Tocopherol Content: -Tocopherol ( -toc) activity was need to investigate the efficient of this compound in the assayed as described by Backer et al. [2]. The -toc enhancement of antioxidant potentials in white radish content was calculated using a standard graph made with plants in order increase their medicinal properties and known amount of -toc and expressed in mg g fresh making them valuable tuber crop. Hence, this study weight (FW). aims to evaluate the ability of triazole to enhance the antioxidant potentials and membrane integrity, with Statistical Analysis: Statistical analysis was special emphasis to antioxidant potential and membrane performed using the one-way analysis of variance integrity constituents. Raphanus sativus (white radish) (ANOVA) followed by the Duncan s multiple range test is an important vegetable crop in India and south east (DMRT). The values mean ±SD for six samples in each countries. The leaves and tubers of radish are used to group p values <.5 were considered as significant. prepare salad and also cooked as vegetables. It is rich in vitamin C and minerals like sulphur. It is also used as RESULT AND DISCUSSION a medicine in currying liver disorders and jaundice. This tuber crops are rich source of energy for people living Triazole treatment increased the non-enzymatic under sustenance level since, it is available at a cheaper antioxidant AA, content (Table, Fig. ) in shoot and price for the poor people. tuber when compared to control plant. Among the organs tuber had higher AA content when compared to the MATERIALS AND METHODS shoot. -tocopherorl content also increase in both organs by triazole treatment, when compared to compared to The seeds were obtained from mahyco-maharashtra control plant. Like wise reduced glutothione content also. hybrid seeds co. Ltd. Maharashtra. India and planted at increased in both organ by 5mg triadimefon and 5mg the botanical garden of the Annamalai University. Two hexaconazole treated plant when compare to control seeds were sown in each plastic pot of 3cm diameter and plant among the treatments triadimefon had higher 3cm height containing 3 kg of soil mixture containing red content when compared to hexaconazole treated one. soil, sand and farm yard manure at :: ratio. Then the AA has been proposed to have roles in regulation of seedling thinned to one per pot on 6th day after sowing. photosynthesis [2], cell expansion and trans-membrane Triadimefon was obtained from Bayer, Germany and electron transport [22]. Triazole increased the level of the hexaconazole was obtained from imperial chemical antioxidant like, AA, -tocopherol in seedlings and industries, England. protected membranes by preventing or reducing oxidative mg L triadimefon and 5mg L hexaconazole were damage [2]. AA acts as an antioxidant, protecting cells used for this study. The seedlings were treated against oxidative stress. AA has the capacity to eliminate with deionized water (control), mg L triadimefon and different AOS including signet oxygen, super oxide and 5mg L hexaconazole solution alone per plant on 8, 23, 38 hydroxyl radicals. and 53 days after sowing (DAS). Then the plants were -Tocopherol content increased with triazole harvested randomly on 3 and 6 DAS and separated into treatment in radish (Table 2, Fig. 2). It is synthesized in the tuber and shoot and used for extraction and assay of chloroplasts and closely associated with the thylokoid antioxidant potentials of radish plant. membrane of the chloroplasts. The thylakoid membrane, which contains substantial unsaturated lipids, is one of Ascorbic Acid Content: Ascorbic acid (AA) content the major sites of oxidative damage through lipid was assayed as described by Omaye et al. [8]. The AA peroxidation. [7,8]. Triazole increased the antioxidant such content was determined using a standard curve prepared as -tocopherol and ascorbate levels and enhanced with AA and the results were expressed in mg g dry activities of peroxidase and catalase in tomato. The GSH weight (DW). content was found increased under triazole application in radish (Table 3, Fig. 3). The increase in GSH can be Reduced Glutathione: The GSH content was assayed as correlated with its ability to scavenge single oxygen, described by Griffith and Meister [9]. GSH contents were peroxides and hydroxyl radicals and is involved in expressed in µg g fresh weight (FW). recycling of AA in the ascorbate glutathione pathway in 64

3 Table : Effect of mg L- TDM and 5mg L- HEX on AA content of shoot and tubers of radish plant (values one given as mean ± SD of six replicates expressed in µg g- F.W) Das Control TDM mg L HEX 5-mg L (8.94) 3.5 (6.58) (8.42) 46.9 (.53) (24.36) (25.42) (43.48) (32.34) Fig. : Effect of mg L- TDM and 5mg L- HEX on AA content of shoot and tubers of radish plant (values one given as mean ± SD of six replicates expressed in mg g- F.W) Fig. 2: Effect of TODM and HEX on a - TOC content of shoot and tuber of radish plant (values are given as mean ± SD of six replicates expressed in mg g- F.W) Fig. 3: Effect of TDM and HEX on GSH content of shoot and tubers of radish plant (values one given as mean ± SD of six replicates expressed in mg g- F.W) Table 2: Effect of TODM and HEX on -TOC content of shoot and tuber of radish plant (values are given as mean ± SD of six replicates expressed in µg g- F.W) Das Control TDM mg L HEX 5-mg L (.4) 6.54 (4.36) (6.92) 9.2 (26.76) (7.46) 6.58 (2.64) (2.65).22 (8.65) Table 3: Effect of TDM and HEX on GSH content of shoot and tubers of radish plant (values one given as mean ± SD of six replicates expressed in µg g- F.W) Das Control TDM HEX chloroplasts[23]. One of the triazole of ketoconazole treated plants can increase the riboflavin content can increase the membrane stability and prevent membrane degradation due to oxidation of the lipid component of the membrane by the reactive oxygen species [24-27]. It is involved in lipid peroxidation and oxidized to act as an electron acceptor. From out results, it can be concluded that the TDM, HEX application can enhance largely the non-enzymatic antioxidant quantity, which is great importance in impairing economic values of the plant. REFERENCE. Davis, D.G. and H.R. Swanson, 2. Activity of stress-related enzymes in the perennial weed leafy spurge (Euphorbia esula L.). Env. Exp. Bot., 46:

4 2. Gehlot, H.S., A. Upadhaya, T.D. Davis and 3. Foyer, C.H., 996. Oxygen metabolism and electron N. Sankhla, 989. Growth and organonensis is moth transport in photosynthesis. In: Oxidative stress and bean callus was affected by paclobutrazol, Plant Cell the molecular biology of antioxidant defenses (ed.). Physiol., 3: J. Scandalios. Cold spring Harbor Laboratory Press, 3. Asada, K., 992. Ascorbate peroxidase-a hydrogen- New York, pp: scavenging enzyme in plants, Physiol. Plant, 4. Huner, N.P.A., G. Oquist and F. Sarhan, 998. Energy 85: balance and acclimation to light and cold, Trends 4. Mehlhorn, H., M. Lelandais, H.G. Korth and Plant Sci., 3: C.H. Foyer, 996. Ascorbate is the natural 5. Dodge, A.D., 97. The mode of action of substrate for plant peroxidases, FEBS. Lett., bipyridylium herbicides, paraquat and diquat, 378: Endeavour, 3: Kraus, T.E., B.D. Mc Kersie and R.A. Fletcher, Scandalios, J.G., 993. Oxygen stress and superoxide Paclobutrazol induced tolerance of wheat leaves to dismutase, Plant Physiol., : 7-2. paraquat may involve increased antioxidant enzyme 7. Steffen, K.L., 99. Avoidance of photooxidative activity, J. Plant Physiol., 45: stress, balancing energy flux within the chloroplast. 6. Jaleel, C.A., R. Gopi, G.M.A. Lakshmanan and In active oxygen/oxidative stress and plant R. Panneerselvam, 26. Triadimefon induced metabolism (ed.). E.J. Pell and K.L. Steffen. Current changes in the antioxidant metabolism and ajmalicine topics in plant physiology, Amer. Soc. Plant Physiol. production in Catharanthus roseus (L.) G. Don, Rockville., 6: 9-3. Plant Sci., 7: Omaye, S.T., J.D. Turn bull and H.E. Sauberilick, 7. Jaleel., C.A., R. Gopi, P. Manivannan 979. Selected methods for the determination of and R. Panneerselvam, 27b. Responses of ascorbic acid in animal cells, tissues and fluids. antioxidant defense system of Catharanthus roseus Method Enzymol., 62: 3-. Academic Press: (L.) G. Don. to paclobutrazol treatment under salinity, New York. Acta. Physiol. Plant, 29: Griffith, O.W. and A. Meister, Jaleel, C.A., R. Gopi, P. Manivannan and Potent and specific inhibition of glutathione R. Panneerselvam, 27c. Responses of antioxidant synthesis by buthionine sulfoximine (s-ndefense system of Catharanthus roseus (L.) G. Don. butylhomocysteine sulfoximine). J. Biol. Chem., to paclobutrazol treatment under salinity, Acta 254: Physiol. Plantarum, 29: Backer, H., O. Frank, B. De Angells and S. Feingold, 9. Jaleel, C.A., P. Manivannan, A. Kishorekumar, 98. Plasma tocopherol in man at various times after B. Sankar, R. Gopi, R. Somasundaram and ingesting free or acetylated tocopherol. Nutr. Res. R. Panneerselvam, 27d. Alterations in Internat, 2: osmoregulation, antioxidant enzymes and indole 2. Willekens, H., C. Langebartels, C. Tire, alkaloid levels in Catharanthus roseus exposed M. Vanmontagu, D. Inze and W. Vancamp, to water deficit, Colloids Surf. B: Biointerfaces, 994. Differential expression of catalase gene 59: in Nicotiana plumbagini folia L. Proceedings. Manivannan, P., C.A. Jaleel, A. Kishorekumar, of the National Academy of Sci., USA B. Sankar, R. Somasundaram, R. Sridharan and 9: R. Panneerselvam, 27a. Propiconazole induced 22. Shaaltiel, Y. and J. Gressel, 986. changes in antioxidant metabolism and drought Multi enzyme oxygen radical detoxifying stress amelioration in Vigna unguiculata (L.) Walp, system correlated with paraquat resistance in Colloids Surf. B: Biointerfaces, 57: Conyza bonariensis, Pesti. Biochem. Physiol.,. McDermott, J.H., 2. Antioxidant Nutrients: 26: Current dietary recommendations and research 23. Ella, E.S., O. Ito and K. Tanaka, 998. Role of update, J. Am. Pharm. Assoc., 4: ascorbate and active oxygen scavenging enzymes in 2. Slater, T.F., 984. Free radical mechanisms in tissue post submergence injury in rice 4. Ann. Sci. Con. injury, Biochem. J., 222: -5. Fed. Crop. Sci. Soc. Philippines, 23:

5 24. Cooper, M., F.A. Van Eeuwijk, S.C. Chapman, 26. Kraus, T.E., B.D. Mc Kersie and R.A. Fletcher, 995. D.W. Podlich and C. Löffler, 26. Genotype by- Paclobutrazol induced tolerance of wheat leaves to environment interactions under water-limited paraquat may involve increased antioxidant enzyme conditions. In: Ribaut JM (ed) Drought Adaptation activity, J. Plant Physiol., 45: in Cereals. Haworth Press, Inc, pp: Kopyra, M. And E.A. Gwozdz, 23. Antioxidant 25. Kraus, T.E. and R.A. Fletcher, 994. Paclobutrazol enzymes in paraquat and cadmium resistant cell lines protects wheat seedlings from heat and paraquat of horseradish, Biol. Lett., 4: injury. Is detoxification of active oxygen involved? Plant Cell Physiol., 35: