Chen, S., Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou 571737, China
Heuer, B., Institute of Soil, Water and Environmental Sciences, ARO, Volcani Center, Bet Dagan 50250, Israel

Tomatoes are classified as moderately salt-tolerant crops, but they are unable to synthesize glycinebetaine (GB), a compound that alleviates salinity-induced inhibition of plant growth. We investigated the effects of salinity on the antioxidative system of tolerant/susceptible genotypes of tomato. In the susceptible genotype's (F144) hypocotyls and radicles, the activities of superoxide dismutase (SOD), l-ascorbate oxidase (l-AAO), ascorbate peroxidase (APX) and catalase increased under salt stress, whereas that of peroxidase (POD) II decreased slightly. In the relatively tolerant genotype Patio, salt stress made little difference in the hypocotyls, whereas the activities of SOD, l-AAO, APX and POD increased significantly in the radicles. The effect of exogenous application of GB under salt stress on antioxidative enzyme activity was also investigated. The results constitute an important step in the elucidation of mechanisms underlying resistance to salinity. © 2013 Elsevier B.V.