Re: Why does asprin prolong a cut flower?

Commercial cut flower preservatives usually contain sucrose, an acid, and a 
biocide. Aspirin could possibly act in either of the latter two capacities. 
Leslie and Romani (Plant Physiology 88:833-837) reported that salicylic acid 
inhibits ethylene biosynthesis (aspirin is acetylsalicylic acid).  Ethylene 
greatly shortens the life of cut flowers, especially carnations, so that could 
be an explanation as well.

Ken Post in his 1949 text, Florist Crop Production and Marketing, (NY: Orange 
Judd) noted a study that found that two aspirins in 1.5 pints of water increased 
the life of gladioli from 10 to 14 days. I have not 
seen the original citation - Pridham, A.M.S. 1925. Keeping flowers by cold 
storage. Florist's Review 56(1439):19-20 [June 25].