Effects of Ethylene on Potato Tuber Respiration

Treatment of potato tubers (Solanum tuberosum L.) with ethylene gas causes a rapid rise in their respiration rate, reaching 5 to 10 times the rate of untreated tubers over 30 hours of treatment and then falling slowly. The response shows a lag of 8 hours, and more than 24 hours of exposure is required for maximum effect; the temperature optimum is near 25 C. In sensitivity to low concentrations and dependence on temperature, the phenomenon is similar to the effect of ethylene on the respiration of climacteric and nonclimacteric fruits. Treated potato tubers returned to air recover their sensitivity to ethylene more slowly than do nonclimacteric fruits (e.g., mature green oranges). It is proposed that the respiratory rise characteristic of ripening in climacteric fruits and of the wound response in plant tissues is induced by a rise in endogenous tissue ethylene.