The Relationship Between Yield and the Antioxidant Defense System in Tomatoes Grown Under Heat Stress

Abstract

Four putative heat-tolerant tomato (Lycopersicum esculentum) cultivars (Tamasabro, Heat Wave, LHT-24, and Solar Set) and one putative heat-sensitive tomato cultivar (Floradade) were grown in the field under non-stress (average daily temperature of 26 degrees C) and heat-stress (average daily temperature of 34 degrees C) conditions. At anthesis, approximately five weeks after being transplanted to the field, leaf samples were collected for antioxidant analyses. Yield was determined by harvesting ripe fruit seven weeks after the collection of leaf samples. Heat stress resulted in a 79.1% decrease in yield for the heat-sensitive Floradade, while the fruit yield in the heat-tolerant cultivars Heat Wave, LHT-24, Solar Set, and Tamasabro was reduced 51.5%, 22.1%, 43.8%, and 34.8% respectively. When grown under heat stress, antioxidant activities were also greater in the heat-tolerant cultivars. Superoxide dismutase (SOD) activity increased up to 9-fold in the heat-tolerant cultivars but decreased 83.1% in the heat-sensitive Floradade. Catalase, peroxidase, and ascorbate peroxidase activity increased significantly in all cultivars. Only Heat Wave showed a significant increase in glutathione reductase in response to heat stress but all heat-tolerant cultivars exhibited significantly lower oxidized ascorbate/reduced ascorbate ratios, greater reduced glutathione/oxidized glutathione rations, and greater alpha-tocopherol concentrations compared to the heat-sensitive cultivar Floridade. These data indicate that the more heat-tolerant cultivars had an enhanced capacity for scavenging active oxygen species and a more active ascorbate-glutathione cycle and suggest a strong correlation between the ability to up-regulate the antioxidant defense system and the ability of tomatoes to produce greater yields when grown under heat stress.

A comparative study of antioxidative defense system in the copper and temperature acclimated strains of Anabaena doliolum

“…Further, increase in GR can be directly corroborated with APX in concordance with the Halliwel-Asada pathway. This result is supported by the findings of Rainwater et al (1996) in heat tolerant tomato (Lycopersicum esculentum). In contrast to the above CAT, APX, and GR showed decreased activity on subjecting wild type organism to Cu 2?…”

“…Besides, the enhanced activity of SOD in 47°C acclimated strain appears to be a requirement for the survival of the cell under high temperature when the rate of ROS production is high (Suzuki and Mittler 2006). These findings are supported by Rainwater et al (1996) in heat tolerant tomato (Lycopersicum esculentum) and by Sairam et al (2000) in wheat (Triticum aestivum). On the other hand on subjecting wild type organism to 50 lM Cu 2?…”

Involvement of G6PDH in heat stress tolerance in the calli from Przewalskia tangutica and Nicotiana tabacum

“…Previous studies have elucidated that heat stress alters the activity of antioxidant enzymes including SOD, CAT, APX, and POD in many plant species such as potato, tomato, wheat and mulberry (Rainwater and Gossett 1996, Sairam et al 2000, Chaitanya et al 2002, Vacca et al 2004. In this study, the activity of APX, CAT, POD and SOD in calli from both P. tangutica and tobacco increased rapidly under heat stress.…”

“…Previous studies have elucidated the importance of maintaining a favorable antioxidative level in plant adaptation to heat stress (Rainwater et al 1996, Sairam et al 2000, Chaitanya et al 2002, Vacca et al 2004. The aim of the present study is to investigate the roles of G6PDH in mediating intracellular redox homeostasis in calli from P. tangutica and tobacco under heat stress.…”

Antioxidant enzymes activity and physiological response of tomato (Lycopersicon esculentum M.) genotypes under mild temperature stress

“…High temperature stress of 35°C caused increase in SOD activity and decrease in activity of CAT, POX, APX, dehydroascorbate reductase and GR and increased levels of antioxidant compounds (Rivero et al 2004). Rainwater et al (1996) and Rivero et al (2004) reported that mild temperature stress increases the activity of antioxidant enzymes to cope up with the initial temperature stress.…”