Abstract
Gummosis, the process of gum exudation from plant tissues, is a common response to wounding, injury by insects and pathogens and some other stresses. In tulips (Tulipa gesneriana L. cv. Apeldoorn), infection by Fusarium oxysporum also induced gummosis. Strenuous effort to know endogenous essential factors to induce gummosis in tulip stems resulted in successful identification of jasmonic acid (JA) and methyl jasmonate (JA-Me) by GC-MS. Total amounts of JA and JA-Me designated as jasmonates in tulip stems were about 70 to 80 ng/gFW by estimating with deuterium labeled ones as internal standards. The application of JA and JA-Me substantially induced gums consisting of glucuronoarabinoxylans with significant increase of ethylene production in tulip stems. The application of ethephon, ethylene-generating compound, however, induced no gummosis although it slightly affected endogenous levels of jasmonates in tulip stems. These results strongly suggest that jasmonates are endogenous essential factors to induce gummosis in tulip stems.
