Sucrose and Sorbitol Effects on Shoot Growth and Proliferation In Vitro, Nutritional Status and Peroxidase and Catalase Isoenzymes of M 9 and MM 106 Apple (Malus domestics Borkh.) Rootstocks

摘要

The in vitro response of the apple rootstocks M 9 and MM 106 to increasing concentrations of sucrose (44, 88, 176 mM) and sorbitol (82, 164, 329 mM) of the culture medium is reported, 88 mM sucrose in the MS medium was the optimal concentration for shoot proliferation of shoots of both the rootstocks as compared to 44 and 176 mM. By increasing sucrose concentration of the medium, shoot length of MM 106 plants increased. However, the effect of the tested sucrose concentrations on shoot length of M 9 plants was not apparent. The in vitro cultures of M 9 shoots produced the greatest number of shoots and the longest shoots per explant with 164 mM of sorbitol in the medium as compared to 82 and 329 mM sorbitol, and to all sucrose concentrations tested. However, the in vitro cultures of MM 106 produced the highest fresh weight per explant, the greatest number of new shoots and the longest shoots per explant with 329 mM of sorbitol in the medium compared to all the other treatments, indicating a genotypiceffect, Mineral concentration in plants was also a function of genotype, carbohydrate source and its concentration in the medium. Explants of both rootstocks treated with sorbitol showed the highest peroxidase and catalase activities in leaves and stems. Although, no differences were found between the electrophoretic profiles of catalase, however, the presence of sucrose and sorbitol in the MS medium remarkably influenced the population of peroxidase isoenzymes in leaves and stems of both rootstocks,