Interrelationship between Abscisic Acid and Ethylene in the Control of Senescence Processes in Carnation Flowers

Abstract

The involvement of abscisic acid (ABA) in senescence of carnation flowers, in the presence of silver ions (which inhibit ethylene action), and aminoethoxyvinylglycine (AVG) (an inhibitor of ethylene synthesis) was studied. ABA stimulated senescence as seen by advancement of ethylene surge, and time to the development of in-rolling of petal margins. ABA also increased the sensitivity of the flowers to ethylene. Silver ions did not affect the time or extent of the ethylene surge, but prevented the appearance of visual senescence symptoms, and lowered the sensitivity to ethylene. AVG delayed the ethylene surge and lowered the maximum rate of ethylene production. Also, AVG delayed the development of visible senscence. In the presence of silver ions, ABA advanced the ethylene surge but senescence symptoms did not develop. The effect of ABA on the parameters measured was prevented by AVG. Thus it is suggested that ABA exerts its effect on senescence via ethylene. The possible involvement of an ABA-ethylene sequence as a mediator of water stress-promoted senescence is discussed.