Ethylene sensitivity: The role of short-chain saturated fatty acids in pollination-induced senescence of Petunia hybrida flowers

Normal and pollination-induced senescence of Petunia hybrida L cv. Pink Cascade flowers is accompanied by an increase in the sensitivity of the corolla to ethylene as indicated by an acceleration in the rate of corolla bluing after exposure to exogenous ethylene. Pollination resulted in the production of short-chain saturated fatty acids ranging in chain length from C₆ to C₁₀. Following pollination, these acids are synthesized in the stylar tissue via the acetate pathway within the first 12 hours. The fatty acids are transported rapidly to the corolla where they induce an increase in ethylene sensitivity. In unpollinated flowers, these acids are produced in the corolla during the early stages of senescence. Although the levels of these fatty acids decrease rapidly during the final stages of senescence, a significant increase in ethylene sensitivity could be detected prior to the decrease. It appears that the increase in ethylene sensitivity caused by the synthesis of short-chain saturated fatty acids occurs concurrently, but independent from ethylene synthesis.