노쇠 중인 애기장대( Arabidopsis thaliana L. ) 잎에서 Salicylic acid에 의하여 유도된 Catalase와 Glutathione reductase 동위효소의 발달

The biochemical effects of salicylic acid( SA ) on the leaf senescence of Arabidopsis thaliana were investigated in parallel with the assay of its influence on the development of antioxidant enzymes. SA treatment significantly inhibited the malondialdehyde ( a lipid peroxidation product ) production and chlorophyll loss in senescing leaves during 3 day dark incubation compared to the control. The spectrophotometric analysis of antioxidant enzymes showed that SA treatment caused the increases of catalase, guaiacol peroxidase and glutathione reductase activities. On the catalase isozyme profiles, a CAT3 isozyme band appeared newly only in SA-treated leaves( 0.5 mM and 1.0 mM SA ) at day 1 and then disappeared at day 2 after dark incubation. The intensity of CAT3 band was more strong in the 1.0 mM SA treatment. In the case of glutathione reductase isozymes, SA treatment also stimulated the pre-existing GR3 isozyme activity and induced a new additional GR isozyme(◀) at day 2 after dark incubation. Therefore, it can be assumed that SA may be involved in the induction of antioxidant enzymes leading to the retardation of leaf senescene.