UC Davis

Ethylene production was measured from excised 10-mm apical and subapical root segments from 50 cultivars in 19 species of 7 families. Monocotyledonous species tended to have much lower rates of ethylene production than dicotyledonous species. Ethylene production was generally higher in apical root segments than in subapical segments within 1 h of wounding. However, cultivars of Cucumis melo, C. sativus, Helianthus annuus, Hibiscus esculentus, and Zea mays had higher rates of ethylene production from subapical segments. In apical root segments, Phaseolus aureus cv. Berken had the highest ethylene production rate (76.7 etal g(-1) h(-1)), while Zea mays cv. Silver Queen had the lowest rate (0.6 etal g(-1) h(-1)). In subapical root segments, Cucumis sativus cv. Armenian had the highest rate (55.7 etal g(-1) h(-1)), while Zea mays cv. Silver Queen again had the lowest rate (0.6 etal g(-1) h(-1)). The many different responses in magnitude and kinetics of wound-induced ethylene production among the species, cultivars and tissues should provide interesting and useful systems with which to study wound responses and induced ethylene production.