Specific Inhibitors of Ethylene Biosynthesis Are Used Commercially to Preserve Cut Flowers
Specific inhibitors of ethylene biosynthesis and action have proven useful in the postharvest preservation of flowers. Silver (Ag+) has been used extensively to increase the longevity of cut carnations and several other flowers. The potent inhibitor AVG retards fruit ripening and flower fading, but its commercial use has not yet been approved by regulatory agencies. The strong, offensive odor of trans-cyclooctene precludes its use in agriculture. On the other hand, the ethylene binding inhibitor 1-methylcyclopropene, which is marketed under the trade name EthylBloc®, is nearly odorless and is used for a variety of postharvest applications, most notably increasing the shelf life of cut flowers. It has also been commercialized as “SmartFreshSM” to help maintain the freshness and quality of fruits such as apples and melons during storage and shipping. The near future may see a variety of agriculturally important species that have been genetically modified to manipulate the biosynthesis of ethylene or its perception. The inhibition of ripening in tomato by expression of an antisense version of ACC synthase and ACC oxidase has already been mentioned. Another example of this technology is in petunia, in which ethylene biosynthesis has been blocked by transformation of an antisense version of ACC oxidase. Senescence and petal wilting of cut flowers are delayed for weeks in these transgenic plants.