Abstract: To investigate the effects of SHAM and MJ in vitro on corm formation in Gladiolus hybridus 'Rose Supreme', the contents of total soluble protein, endogenous methyl jasmonate (MJ) and carbohydrates as well as the activities of LOX-1 and antioxidant enzymes were examined under different treatments. LOX isozymes were also analysized. The results showed that, under the SHAM treatment, corm formation was obviously delayed and reduced in terms of frequency and corm fresh mass and diameter and that the concentrations of total protein, MJ and carbohydrates, and the activities of antioxidant enzymes and LOX-1 were all reduced compared to the control. The activities of LOX isozymes became weaker with two isozyme bands disappeared. In contrast, these physiological and biochemical indexes were increased under MJ treatments, in which, 0.5mmol·L^-1 was the optimal concentration for promoting corm formation in Gladiolus. These results suggested that corm formation could be improved by MJ but suppressed by SHAM through regulating the LOX activity, resulting in carbohydrate accumulation and increase of antioxidant enzymes activities in Gladiolus hybridus.

Key words: Gladiolus hybridus, corm, Lipoxygenase, salicylhydroxamic acid, methyl jasmonate, antioxidant enzymes, carbohydrate