Low-Temperature Triggered Varied Antioxidant Responses in Tomato

Low temperature can delay growth and development, reduce productivity, or cause plant death. An experiment was carried out to determine the most sensitive and most tolerant tomato (Solanum lycopersicum L.; variety S-22, Selection N-5, Pusa Gorav, K-21, Pusa Ruby, Hera Research, and PKM-1) to low temperature. Forty-day-old seedlings were exposed to day/night temperatures of 10/3°C, 12/7°C, 20/14°C, or 25/18°C (control) for 24 h in a plant growth chamber and then transferred to ambient environmental conditions in a net house and maintained for 60 days. Decreasing temperature led to decreases in growth, chlorophyll content, and photosynthesis rate in all varieties. Activity of antioxidant enzymes catalase, peroxidase, and superoxide dismutase and proline accumulation in leaves increased in all varieties as temperature decreased. Variety S-22 had the most antioxidant enzyme activity and proline accumulation and ‘PKM-1’ had the lowest antioxidant enzyme activity and proline content; these were classified as tolerant and sensitive, respectively. Tolerant tomato varieties provide options for producers where low temperature can interfere with plant development.