Two wheat genotypes, C 306 (tolerant) and PBW 343 (susceptible to temperature stress) were grown in growth chambers in the phytotron facility of IARI, New Delhi. The plants were maintained at 18/23°C (control) and 25/35°C (temperature stress) night/day temperatures after maximum tillering. Water potential was significantly reduced at anthesis, and at 7 and 15 days after anthesis in both genotypes in the heat stress treatment, and a greater reduction was recorded in PBW 343. The membrane stability index was also lower in the heat stress treatment in both genotypes at the vegetative stage, at anthesis and at 15 days after anthesis, and a greater reduction was observed in PBW 343 than in C 306. The hydrogen peroxide content increased as the plants advanced in age, and a higher hydrogen peroxide content was recorded in PBW 343 than in C 306 at different stages of growth in the heat stress treatment. The superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR) and peroxidase (POX) activities increased significantly at all stages of growth in C 306 in response to heat stress treatment, while PBW 343 showed a significant reduction in catalase, glutathione reductase and peroxidase activities in the high temperature treatment. Northern blot showed a significant increase in the APX -mRNA level under heat stress at the vegetative and anthesis stages, and the expression was greater in C 306. From the results it is apparent that the antioxidant defence mechanism plays an important role in the heat stress tolerance of wheat genotypes.
Aebi, H. (1984): Catalase in vitro . Method. Enzymol. , 105 , 121–126.
Aebi H. , 'Catalase in vitro ' (1984 ) 105 Method. Enzymol. : 121 -126 .
Agarwal, S., Sairam, R. K., Srivastava, G. C., Tyagi, A., Meena, R. C. (2005): Role of ABA, salicylic acid, calcium and hydrogen peroxide on antioxidant enzymes induction in wheat seedlings. Plant Sci. , 169 , 559–570.
Meena R. C. , 'Role of ABA, salicylic acid, calcium and hydrogen peroxide on antioxidant enzymes induction in wheat seedlings ' (2005 ) 169 Plant Sci. : 559 -570 .
Al-Khatib, K., Paulsen, G. M. (1999): High temperature effects on photosynthetic processes in temperate and tropical cereals. Crop Sci. , 39 , 119–125.
Paulsen G. M. , 'High temperature effects on photosynthetic processes in temperate and tropical cereals ' (1999 ) 39 Crop Sci. : 119 -125 .
Almeselmani, M. (2006): Studies on the mechanism of high temperature stress tolerance in wheat (Triticum aestivum L.) genotypes . Ph.D. Thesis, Indian Agricultural Research Institute, New Delhi, India.
Almeselmani M. , '', in Studies on the mechanism of high temperature stress tolerance in wheat (Triticum aestivum L.) genotypes , (2006 ) -.
Asada, K. (1996): Radical production and scavenging in chloroplasts. pp. 123–150. In: Baker, N. (ed.), Photosynthesis and the Environment . Kluwer Academy Press, Dordrecht.
Asada K. , '', in Photosynthesis and the Environment , (1996 ) -.
Badiani, M., Schenone, G., Paolacci, A., Artemi, F. (1994): Daily fluctuations of antioxidant in bean ( Phaseolus vulgaris L.) leaves. The influence of climatic factors. Agrochimica , 38 , 25–36.
Artemi F. , 'Daily fluctuations of antioxidant in bean (Phaseolus vulgaris L.) leaves. The influence of climatic factors ' (1994 ) 38 Agrochimica : 25 -36 .
Baisak, R., Rana, D., Acharya, P. B. B., Kar, M. (1994): Alteration in the activities of active oxygen scavenging enzymes of wheat leaves subjected to water stress. Plant Cell Physiol. , 35 , 489–495.
Kar M. , 'Alteration in the activities of active oxygen scavenging enzymes of wheat leaves subjected to water stress ' (1994 ) 35 Plant Cell Physiol. : 489 -495 .
Bowler, C., Van Montagu, M., Inze, D. (1992): Superoxide dismutase and stress tolerance. Ann. Rev. Plant Physiol. Plant Mol. Biol. , 43 , 83–116.
Inze D. , 'Superoxide dismutase and stress tolerance ' (1992 ) 43 Ann. Rev. Plant Physiol. Plant Mol. Biol. : 83 -116 .
Castillo, F. I., Penel, I., Greppin, H. (1984): Peroxidase release induced by ozone in Sedum album leaves. Plant Physiol. , 74 , 846–851.
Greppin H. , 'Peroxidase release induced by ozone in Sedum album leaves ' (1984 ) 74 Plant Physiol. : 846 -851 .
Chaitanya, K. V., Sundar, D., Masilamani, S., Ramachandra Reddy, A. (2002): Variation in heat stress-induced antioxidant enzyme activities among three mulberry cultivars. Plant Growth Regul. , 36 , 175–180.
Ramachandra Reddy A. , 'Variation in heat stress-induced antioxidant enzyme activities among three mulberry cultivars ' (2002 ) 36 Plant Growth Regul. : 175 -180 .
Chen, T. H. H., Murata, N. (2002): Enhancement of tolerance of abiotic stress by metabolic engineering of betaines and other compatible solutes. Curr. Opin. Plant Biol. , 5 , 250–257.
Murata N. , 'Enhancement of tolerance of abiotic stress by metabolic engineering of betaines and other compatible solutes ' (2002 ) 5 Curr. Opin. Plant Biol. : 250 -257 .
Christiansen, M. N. (1978): The physiology of plant tolerance to temperature extremes. pp. 173–191. In: Jung, G. A. (ed.), Crop Tolerance to Suboptimal Land Conditions . American Soc. Agron., Wisconsin.
Christiansen M. N. , '', in Crop Tolerance to Suboptimal Land Conditions , (1978 ) -.
Dat, J. F., Lopez-Delgado, H., Foyer, C. H., Scott, I. M. (1998): Parallel changes in H 2 O 2 and catalase during thermotolerance induced by salicylic acid or heat-acclimation in mustard seedlings. Plant Physiol. , 116 , 1351–1357.
Scott I. M. , 'Parallel changes in H2O2 and catalase during thermotolerance induced by salicylic acid or heat-acclimation in mustard seedlings ' (1998 ) 116 Plant Physiol. : 1351 -1357 .
Davidson, J. E., Whyte, B., Bissinger, P. H., Schiestl, R. H. (1996): Oxidative stress is involved in heat induced cell death in Saccharomyces cerevisiae . Proc. Natl. Acad. Sci. USA , 93 , 5116–5121.
Schiestl R. H. , 'Oxidative stress is involved in heat induced cell death in Saccharomyces cerevisiae ' (1996 ) 93 Proc. Natl. Acad. Sci. USA : 5116 -5121 .
Dhindsa, R. S., Dhindsa, P. P., Thorpe, T. A. (1981): Leaf senescence: Correlated with increased levels of membrane permeability and lipid peroxidation, and decreased levels of superoxide dismutase and catalase. J. Exp. Bot. , 32 , 93–101.
Thorpe T. A. , 'Leaf senescence: Correlated with increased levels of membrane permeability and lipid peroxidation, and decreased levels of superoxide dismutase and catalase ' (1981 ) 32 J. Exp. Bot. : 93 -101 .
Feierabend, J., Engel, S. (1986): Photo-inactivation of catalase in vitro and in leaves. Arch. Biochem Biophys. , 251 , 567–576.
Engel S. , 'Photo-inactivation of catalase in vitro and in leaves ' (1986 ) 251 Arch. Biochem Biophys. : 567 -576 .
Fisher, R. A., Byerlee, D. R. (1990): Trends of wheat production in the warmer areas: Major issues and economic considerations. pp. 3–27. In: Saunders, D. A. (ed.), Wheat for Nontraditional, Warm Areas . CIMMYT, Mexico, DF.
Byerlee D. R. , '', in Wheat for Nontraditional, Warm Areas , (1990 ) -.
Foyer, C. H., Lopez-Delgado, H., Dat, J. F., Scott, I. M. (1997): Hydrogen peroxide- and glutathione-associated mechanisms of acclimatory stress tolerance and signaling. Physiol. Plant. , 100 , 241–254.
Scott I. M. , 'Hydrogen peroxide- and glutathione-associated mechanisms of acclimatory stress tolerance and signaling ' (1997 ) 100 Physiol. Plant. : 241 -254 .
Foster, J. G., Hess, J. L. (1980): Responses of superoxide dismutase and glutathione reductase activities in cotton leaf tissue exposed to an atmosphere of enriched oxygen. Plant Physiol. , 66 , 482–487.
Hess J. L. , 'Responses of superoxide dismutase and glutathione reductase activities in cotton leaf tissue exposed to an atmosphere of enriched oxygen ' (1980 ) 66 Plant Physiol. : 482 -487 .
Foster, J. G., Hess, J. L. (1982): Oxygen effects on maize leaf superoxide dismutase and glutathione reductase. Phytochemistry , 21 , 1527–1532.
Hess J. L. , 'Oxygen effects on maize leaf superoxide dismutase and glutathione reductase ' (1982 ) 21 Phytochemistry : 1527 -1532 .
Groden, D., Beck, E. (1979): H 2 O 2 destruction by ascorbate-dependent system from chloroplast. Bichim. Biophys. Acta , 546 , 426–435.
Beck E. , 'H2O2 destruction by ascorbate-dependent system from chloroplast ' (1979 ) 546 Bichim. Biophys. Acta : 426 -435 .
Gupta, A. S., Webb, R. P., Holaday, A. S., Allen, R. D. (1993): Overexpression of superoxide dismutase protects plants from oxidative stress. (Induction of ascorbate peroxidase in superoxide dismutase overexpressing plants). Plant Physiol. , 103 , 1067–1073.
Allen R. D. , 'Overexpression of superoxide dismutase protects plants from oxidative stress. (Induction of ascorbate peroxidase in superoxide dismutase overexpressing plants) ' (1993 ) 103 Plant Physiol. : 1067 -1073 .
Hoagland, C. R., Arnon, D. I. (1950): The solution-culture method for growing plants without soil. Calif. Agric. Exp. Circ. , 347 , 1036–1043.
Arnon D. I. , 'The solution-culture method for growing plants without soil ' (1950 ) 347 Calif. Agric. Exp. Circ. : 1036 -1043 .
Jagtap, V., Bhargava, S. (1995): Variation in the antioxidant metabolism of drought tolerant and drought susceptible varieties of Sorghum bicolor (L.) Moench. exposed to high light, less water and high temperature stress. J. Plant Physiol. , 145 , 195–197.
Bhargava S. , 'Variation in the antioxidant metabolism of drought tolerant and drought susceptible varieties of Sorghum bicolor (L.) Moench. exposed to high light, less water and high temperature stress ' (1995 ) 145 J. Plant Physiol. : 195 -197 .
Jiang, Y., Huang, B. (2001): Effects of calcium on antioxidant activities and water relations associated with heat tolerance in two cool season grasses. J. Exp. Bot. , 52 , 341–349.
Huang B. , 'Effects of calcium on antioxidant activities and water relations associated with heat tolerance in two cool season grasses ' (2001 ) 52 J. Exp. Bot. : 341 -349 .
Kocsy, G., Laurie, R., Szalai, G., Szilágyi, V., Simon-Sarkadi, L., Galiba, G., de Ronde, J. A. (2005): Genetic manipulation of proline levels affects antioxidants in soybean subjected to simultaneous drought and heat stresses. Physiol. Plant. , 124 , 227–235.
Ronde J. A. , 'Genetic manipulation of proline levels affects antioxidants in soybean subjected to simultaneous drought and heat stresses ' (2005 ) 124 Physiol. Plant. : 227 -235 .
Larkindale, J., Knight, M. R. (2002): Protection against heat stress-induced oxidative damage in Arabidopsis involves calcium, abscisic acid, ethylene, and salicylic acid. Plant Physiol. , 128 , 682–695.
Knight M. R. , 'Protection against heat stress-induced oxidative damage in Arabidopsis involves calcium, abscisic acid, ethylene, and salicylic acid ' (2002 ) 128 Plant Physiol. : 682 -695 .
Larkindale, J., Huang, B. (2004): Thermotolerance and antioxidant systems in Agrostis stolonifera : Involvement of salicylic acid, abscisic acid, calcium, hydrogen peroxide, and ethylene. J. Plant Physiol. , 161 , 405–413.
Huang B. , 'Thermotolerance and antioxidant systems in Agrostis stolonifera: Involvement of salicylic acid, abscisic acid, calcium, hydrogen peroxide, and ethylene ' (2004 ) 161 J. Plant Physiol. : 405 -413 .
Liu, X., Huang, B. (2000): Heat stress injury in relation to membrane lipid peroxidation in creeping bentgrass. Crop Sci. , 40 , 503–510.
Huang B. , 'Heat stress injury in relation to membrane lipid peroxidation in creeping bentgrass ' (2000 ) 40 Crop Sci. : 503 -510 .
Lokhande, S. D., Ogawa, K., Tanaka, A., Hara, T. (2003): Effect of temperature on ascorbate peroxidase activity and flowering of Arabidopsis thaliana ecotypes under different light conditions. J. Plant Physiol. , 160 , 57–64.
Hara T. , 'Effect of temperature on ascorbate peroxidase activity and flowering of Arabidopsis thaliana ecotypes under different light conditions ' (2003 ) 160 J. Plant Physiol. : 57 -64 .
Menconi, M., Sgherri, C. L. M., Pinzino, C., Navari-Izzo, F. (1995): Activated oxygen production and detoxification in wheat plants subjected to a water deficit programme. J. Exp. Bot. , 46 , 1123–1130.
Navari-Izzo F. , 'Activated oxygen production and detoxification in wheat plants subjected to a water deficit programme ' (1995 ) 46 J. Exp. Bot. : 1123 -1130 .
Mishra, R. K., Singhal, G. S. (1992): Function of photosynthetic apparatus of intact wheat leaves under high light and heat stress and its relationship with thylakoid lipids. Plant Physiol. , 98 , 1–6.
Singhal G. S. , 'Function of photosynthetic apparatus of intact wheat leaves under high light and heat stress and its relationship with thylakoid lipids ' (1992 ) 98 Plant Physiol. : 1 -6 .
Nakano, Y., Asada, K. (1981): Hydrogen peroxide is scavenged by ascorbate specific peroxides in spinach chloroplasts. Plant Cell Physiol. , 22 , 867–880.
Asada K. , 'Hydrogen peroxide is scavenged by ascorbate specific peroxides in spinach chloroplasts ' (1981 ) 22 Plant Cell Physiol. : 867 -880 .
Noctor, G., Foyer, C. H. (1998): Ascorbate and glutathione: keeping active oxygen under control. Annu. Rev. Plant Physiol. Mol. Biol. , 49 , 249–279.
Foyer C. H. , 'Ascorbate and glutathione: keeping active oxygen under control ' (1998 ) 49 Annu. Rev. Plant Physiol. Mol. Biol. : 249 -279 .
Pastori, G. M., Trippi, V. S. (1992): Oxidative stress induces high rate of glutathione reductase synthesis in a drought resistant maize strain. Plant Cell Physiol. , 33 , 957–961.
Trippi V. S. , 'Oxidative stress induces high rate of glutathione reductase synthesis in a drought resistant maize strain ' (1992 ) 33 Plant Cell Physiol. : 957 -961 .
Pastori, G. M., Foyer, C. H.(2002): Common components, networks, and pathways of cross-tolerance to stress. The central role of ‘redox’ and abscisic acid-mediated controls. Plant Physiol. , 129 , 7460–7468.
Foyer C. H. , 'Common components, networks, and pathways of cross-tolerance to stress. The central role of ‘redox’ and abscisic acid-mediated controls ' (2002 ) 129 Plant Physiol. : 7460 -7468 .
Polle, A. (1997): Defense against photo-oxidative damage in plants. pp. 785–813. In: Scandalios, J. (ed.), Oxidative Stress and The Molecular Biology of Antioxidant Defence . Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY.
Polle A. , '', in Oxidative Stress and The Molecular Biology of Antioxidant Defence , (1997 ) -.
Price, A. H., Atherton, N. M., Hendry, G. A. F. (1989): Plants under drought-stress generated activated oxygen. Free Radical Res. Commun. , 8 , 61–66.
Hendry G. A. F. , 'Plants under drought-stress generated activated oxygen ' (1989 ) 8 Free Radical Res. Commun. : 61 -66 .
Rao, M. V., Paliyath, G., Ormrod, D. P., Murr, D. P., Watkins, C. B. (1997): Influence of salicylic acid on H 2 O 2 production, oxidative stress and H 2 O 2 metabolizing enzymes. Plant Physiol. , 115 , 137–149.
Watkins C. B. , 'Influence of salicylic acid on H2O2 production, oxidative stress and H2O2 metabolizing enzymes ' (1997 ) 115 Plant Physiol. : 137 -149 .
Rui, R. L., Nie, Y. Q., Tong, H. Y. (1990): SOD activity as a parameter for screening stress tolerant germplasm resources in sweet potato ( Ipomoea batatas L.). Jiangsu J. Agr. Sci. , 6 , 52–56.
Tong H. Y. , 'SOD activity as a parameter for screening stress tolerant germplasm resources in sweet potato (Ipomoea batatas L.) ' (1990 ) 6 Jiangsu J. Agr. Sci. : 52 -56 .
Sairam, R. K. (1994): Effect of moisture stress on physiological activities of two contrasting wheat genotypes. Indian J. Expt. Biol. , 32 , 594–597.
Sairam R. K. , 'Effect of moisture stress on physiological activities of two contrasting wheat genotypes ' (1994 ) 32 Indian J. Expt. Biol. : 594 -597 .
Sairam, R. K., Deshmukh, P. S., Shukla, D. S. (1997): Tolerance of drought and temperature stress in relation to increased antioxidant enzyme activity in wheat. J. Agron. Crop Sci. , 178 , 171–178.
Shukla D. S. , 'Tolerance of drought and temperature stress in relation to increased antioxidant enzyme activity in wheat ' (1997 ) 178 J. Agron. Crop Sci. : 171 -178 .
Sairam, R. K., Deshmukh, P. S., Saxena, D. C. (1998): Role of antioxidant systems in wheat genotypes tolerance to water stress. Biol. Plant. , 41 , 387–394.
Saxena D. C. , 'Role of antioxidant systems in wheat genotypes tolerance to water stress ' (1998 ) 41 Biol. Plant. : 387 -394 .
Sairam, R. K., Srivastava, G. C., Saxena, D. C. (2000): Increased antioxidant activity under elevated temperature: a mechanism of heat stress tolerance in wheat genotypes. Biol. Plant. , 43 , 245–251.
Saxena D. C. , 'Increased antioxidant activity under elevated temperature: a mechanism of heat stress tolerance in wheat genotypes ' (2000 ) 43 Biol. Plant. : 245 -251 .
Sambrook, J., Fritsch, E. F., Maniatis, T. (1989): Molecular Cloning: A Laboratory Manual , 2 nd ed. Cold Spring Harbor Laboratory, Cold Spring Harbor, NY.
Maniatis T. , '', in Molecular Cloning: A Laboratory Manual , (1989 ) -.
Scholander, P. L., Hammel, H. T., Bradstreet, E. D., Hemmingsen, E. Q. (1964): Hydrostatic pressure and osmotic potential in leaves of mangroves and some other plants. Proc. Nat. Acad. Sci. USA , 52 , 119–125.
Hemmingsen E. Q. , 'Hydrostatic pressure and osmotic potential in leaves of mangroves and some other plants ' (1964 ) 52 Proc. Nat. Acad. Sci. USA : 119 -125 .
Singh, A. K., Singhal, G. S. (2001): Effect of irradiance on the thermal stability of thylakoid membrane isolated from acclimated wheat leaves. Photosynthetica , 39 , 23–27.
Singhal G. S. , 'Effect of irradiance on the thermal stability of thylakoid membrane isolated from acclimated wheat leaves ' (2001 ) 39 Photosynthetica : 23 -27 .
Smirnoff, N. (1993): The role of active oxygen in the responses of plants to water deficit and desiccation. New Phytol. , 125 , 27–58.
Smirnoff N. , 'The role of active oxygen in the responses of plants to water deficit and desiccation ' (1993 ) 125 New Phytol. : 27 -58 .
Smirnoff, N., Colombe, S. V. (1988): Drought influences the activity of enzymes of the chloroplast hydrogen peroxide scavenging system. J. Exp. Bot. , 39 , 1097–1108.
Colombe S. V. , 'Drought influences the activity of enzymes of the chloroplast hydrogen peroxide scavenging system ' (1988 ) 39 J. Exp. Bot. : 1097 -1108 .
Smith, I. K., Vierheller, T. L., Thorne, C. A. (1988): Assay of glutathione reductase in crude tissue homogenates using 5,5′-dithiobis (2-nitrobenzoic acid). Anal. Biochem. , 175 , 408–413.
Thorne C. A. , 'Assay of glutathione reductase in crude tissue homogenates using 5,5′-dithiobis (2-nitrobenzoic acid) ' (1988 ) 175 Anal. Biochem. : 408 -413 .
Upadhyaya, A., Davis, T. D., Larsen, N. H., Walser, R. H., Sankhla, N. (1990): Uniconazoleinduced thermotolerance in soybean seedling root tissue. Physiol. Plant. , 79 , 78–84.
Sankhla N. , 'Uniconazoleinduced thermotolerance in soybean seedling root tissue ' (1990 ) 79 Physiol. Plant. : 78 -84 .
Willekens, H., Inze, D., Van Montagu, M., Van Camp, W. (1995): Catalase in plants. Mol. Breeding , 1 , 207–228.
Camp W. , 'Catalase in plants ' (1995 ) 1 Mol. Breeding : 207 -228 .
Zhang, J. X., Kirkham, M. B. (1994): Drought-stress-induced changes in activities of superoxide dismutase, catalase, and peroxidase in wheat species. Plant Cell Physiol. , 35 , 785–791.
Kirkham M. B. , 'Drought-stress-induced changes in activities of superoxide dismutase, catalase, and peroxidase in wheat species ' (1994 ) 35 Plant Cell Physiol. : 785 -791 .
Zhau, R. G., Fan, Z. H., Li, X. Z., Wang, Z. W., Han, W. (1995): The effect of heat acclimation on membrane thermo-stability and reactive enzyme activity. Acta Agron. Sin. , 21 , 568–572.
Han W. , 'The effect of heat acclimation on membrane thermo-stability and reactive enzyme activity ' (1995 ) 21 Acta Agron. Sin. : 568 -572 .