Effect of controlled hydration treatment on germination and seedling growth under salt stress during development in tomato seeds

Tomato (Lycopersicum esculentum Mill.) seed lots harvested 60, 70, 80 and 90 and 50, 60, 70 and 80DAA (days after anthesis) in 1998 and 1999, respectively, were treated with controlled hydration at 25degreesC for 26h. Following drying, treated and untreated seeds were incubated (at 25degreesC) and emerged (in peat moss) in 100 mM NaCI in order to assess the effect of the treatment on germination (total, normal and abnormal germination) and seedling growth (emergence, mean emergence time, seedling fresh and dry weight, hypocotyl and cotyledon length) in saline conditions. Na and Cl contents of the treated and untreated seedlings were also determined. The treatment enhanced normal germination, emergence, mean germination time, seedling fresh and dry weights, hypocotyl and cotyledon length, compared with untreated seeds. Treated seeds produced seedlings that had higher Na and Cl contents compare with control under salt stress. Results indicated that controlled-hydration treatment increased resistance to salt stress in all developmental stages.