Chilling stress and physiological changes in Sorbus domestica grown in vitro: Anti-oxidative system and carbohydrate adjustment

Sorbus domestica is a tree species that is distributed in Southern and Eastern Europe as well as in Asia Minor and in the North of Africa. It is able to develop and to adapt to different environmental conditions. In the present work, microcuttings of Sorbus domestica were grown in vitro at 23degreesC and compared with shoots grown under different chilling conditions: 10degreesC and 4degreesC. The comparison was carried out up to 21 days. Survival was not affected whilst growth of the shoots was almost inhibited by both cold treatments. Changes in different carbohydrates were measured during the first seven days of chilling. Increasing levels of fructose and glycerol were recorded in Sorbus domestica submitted to chilling while no difference in sucrose content could be observed between control and treated plants. The analyses of the activity of different enzymes involved in the plant's antioxidant systems indicated an increased ascorbate production in the cold-treated shoots. In parallel, there was no evidence for an increased hydrogen peroxide production.