ISHS Acta Horticulturae 618: XXVI International Horticultural Congress: Environmental Stress and Horticulture Crops
SUPEROXIDE DISMUTASE, RIBULOSE 1, 5-BISPHOSPHATE CARBOXYLASE (RUBISCO) AND PHOTOSYNTHETIC RATES OF DROUGHT-TOLERANT AND DROUGHT-SENSITIVE TOMATO CULTIVARS |
| Authors: | S.M. Lutfor Rahman, W.A. Mackay, E. Nawata, T. Sakuratani, A.S.M. Mesbah, B. Quebedeaux |
| Keywords: | Lycopersicon esculentum, cultivar, drought-tolerant and drought-sensitive, rubisco, superoxide dismutase, tomato, water stress |
| Abstract:
The development of drought-tolerant tomato [Lycopersicon esculentum (Mill.)] cultivars for cultivation in hot and dry climates is a long-term research objective in many parts of the developing world. To achieve this end, eco-physiological and biochemical studies on tomato drought tolerance were carried out. The effects of water stress on superoxide dismutase (SOD) in several drought-tolerant and drought-sensitive tomato cultivars were examined. In most of drought-tolerant cultivars, the increase in SOD activities induced by water stress was more rapid and greater than in drought-sensitive cultivars. Under well-watered conditions, drought-tolerant cultivars showed significantly higher SOD activities (496±2.1 Unit/mg protein) than drought-sensitive cultivars (342±1.7 Unit/mg protein). Rubisco activity was reduced by water stress, but the reduction was more rapid and greater in drought-sensitive ‘King Fukuju’ (KF, 45-55%)) than tolerant ‘TM 0126’ (TM, 20-25%). Similar trends were observed for water stress effects on photosynthetic rate (Pr) to those on Rubisco activities. The ability of TM to minimize the reduction in Pr under water stress may be related to its ability to maintain higher rubisco activities. It appears that drought-tolerant tomato cultivars have both an ability to tolerate water deficits and to recover rapidly after re-watering. Our studies suggest that SOD activity should be considered as a screening tool for developing tomato drought tolerance. The importance of the SOD defense system in tomato drought tolerance was confirmed. | |
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