Articles
SUPEROXIDE DISMUTASE, RIBULOSE 1, 5-BISPHOSPHATE CARBOXYLASE (RUBISCO) AND PHOTOSYNTHETIC RATES OF DROUGHT-TOLERANT AND DROUGHT-SENSITIVE TOMATO CULTIVARS
Article number
618_39
Pages
337 – 345
Language
English
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.
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.
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
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