Abstract

The research aims to identify the response of some commercial tomato rootstocks namely Beaufort, Body, Heman, Resistar, Spirit, Vigomax, Yedi to salinity stress with the screening method. The study assays not only non-grafted (cv. Gokce) but also self-grafted plants as control plants in order to demonstrate grafted union effect. The plants were placed in styrofoam on horizontal pots and grown in aerated water culture. Salination was initiated one week after the transplantation of seedlings to the pots. Salinity level was gradually increased up to 300 mM by adding 50 mM NaCl one day interval and plants were left for 10 days at that salinity level. Plants were removed before salt treatment and at 150 and 300 mM NaCl level. They were classified according to the severity of leaf symptoms caused by salinity levels. In addition, scale scoring, leaf number, stem length and diameter, leaf area, total root length per plant and leaf catalase (CAT) and peroxidase (POX) enzyme contents were measured. Furthermore, the plants were separated into shoots and roots for dry matter assimilation. The results demonstrated that salt stress decreased plant vigor, and rootstocks yielded better performance than non- and self-grafted treatments. Beaufort and Yedi appeared as more tolerant genotypes than the others under stress condition. CAT activity decreased while POX activity increased with increased salinity levels and both activities occurred higher in grafted treatments. The study concludes that grafting may be considered as an alternative strategy to enhance salt tolerance in tomato; however, the effects of the grafting may vary for different rootstock genotypes.

Key words: Plant growth, enzyme, grafting, NaCl, screening.