Ethylene effect on extensin and peroxidase distribution in the subapical region of pea epicotyls.

In dark grown pea (Pisum sativum) seedlings ethylene causes the triple response in which elongation growth is inhibited, radial growth is promoted, and orientation of shoots to gravity is altered. The distribution of extensin and peroxidase activity in pea epicotyls upon ethylene treatment was studied by tissue printing on nitrocellulose paper. It was found that the localization of extensin and peroxidase activity changes after 72 and 96 hours of ethylene treatment. In untreated plants, peroxidase activity is detected only in the vascular bundles. Nonetheless, after 72 and 96 hours of ethylene treatment peroxidase activity is hardly detected in the vascular system but present in the epidermal and cortical cells. Extensin increases in the epidermal and cortical cells upon ethylene treatment but it also appears in the vascular system when peroxidase activity is no longer detected.