Flowers, leaves and buds drop basically to protect the flower i.e.from desiccation. The most well-known reason for flowers,leaves and buds to drop is the result of exposure to ethylene,from inside the flower or outside sources. As a reaction to cutting/harvesting, the process of aging starts in the flower. The aging plant growth regulator produced in th e flower is ethylene.In order to fulfill its task of continuation of the species, the flower regenerates as quickly as possible by producing higher concentrations of ethylene. Especially when circumstances become sub-optimal, which they do in the post-harvest period,the flower starts to produce excessive amounts of ethylene. If ethylene is supplied from an outside source, the process of aging is accelerated too. The flower absorbs this outside ethylene,which in its turn acts as an accelerator of the internal aging process. At high concentrations it becomes killing to the flower.In addition, petal drop, leaf drop and shrinking flowers are symptoms of exceeding the acceptable ethylene concentrations in the flower.
Ethylene sources are i.e.:
- ripening fruit
- exhaust from combustion engines
- smoke, industrial or from cigarettes
- yeast, bacteria and fungi
Ethylene-sensitive flowers showing flower, leaf and bud drop are i.e.:
How can you identify ethylene damage in flowers?
- Petal color appears bluish (obvious in roses, carnations)
- Shattering florets in delphiniums, wax flower, limonium or snap dragons. Lots of petals in bottom of sleeves:
- Buds and leaves fall off stems when flowers are handled
- Asiatic and LA hybrid lily buds appear crepe-y or shriveled. Immature buds fall off
- Stock blooms appear shriveled and transparent
- Alstro flowers appear transparent
- White spray Dendrobian orchids appear a weird color of chartreuse green
What can you do to prevent ethylene damage?
Products based on silver thiosulphate (STS), like Chrysal AVB,protect ethylene-sensitive flowers against the negative effects of ethylene. This product should be used at grower level. When correctly applied, the flowers are protected throughout the whole floral chain. Also important is the use of Chrysal Clear Professional at trade level and Chrysal Clear cut flower food at consumer level to keep the flowers in optimal condition and thus less susceptible to ethylene damage.