Evaluation of Current Post-Harvest Handling Practices on Imported Fresh Flowers
PROJECT PROGRESS REPORT- JUNE 1,1999
EVALUATION OF CURRENT POST-HARVEST HANDLING PRACTICES
ON IMPORTED FRESH FLOWERS
by
Terril A. Nell, Ayumi Suzuki, Ria T Leonard, Jim Barrett and
Dave Clark
Environmental Horticulture Department University of Florida
and
Michael Reid and Linda Dodge, University of California - Davis
INDUSTRY NEEDS AND PROJECT OBJECTIVES:
The overall objective of our project is to improve the performance of cut
flowers in the consumers’ home. To that end, we have been focused on several
important Issues, including:
1. The effect of storage and transportation temperatures on flower vase life.
2. The effects of traditional post-harvest prophylaxes (cutting under water,
use of hydration products, warm water etc.) in improving vase life.
3. The effects of biocides, flower food, and ethylene inhibition on a range
of Individual crops.
4. Evaluation of hydration at farm level.
SUMMARY OF WORK CONDUCTED SINCE INCEPTION:
1.
Storage/transportation temperatures and vase life:
AFE support
has enabled us to continue our studies of the effects of storage temperature on
subsequent vase life of a wide range of cut flower species. Typical results are
well demonstrated by the picture below.
Flowers were held at the indicated temperatures for 5 days of simulated
transport, then placed in simulated vase-life conditions for four days before
the picture was taken. Storage at temperatures above 32 had an obvious and
increasingly detrimental effect on the quality and vase life of these and many
other species of flowers. In snapdragon, storage at 32 prevented spike bending,
and greatly delayed floret abscission. We have studied the effect of temperature
on the storage life of more than 20 different flower species and cultivars. In
every case there was a clear benefit of lower temperatures on the life of the
flowers. This finding is of particular concern because our studies have shown
that most cut flowers, domestic and imported, are transported at temperatures
that usually range from 40 to 60 F.
2. Value of traditional prophylaxes:
Our initial studies
indicated that in normal handling of cut flowers, cutting under water,
or the use of rehydration solutions was of minimal benefit.
- Roses and chrysanthemums (Roses: Madame Delbard and First Red;
Chrysanthemum: Herman Do Boon and [flamenco) have been hydrated using Floralife
hydraflor for 1 hour for roses and 30 minutes for chrysanthemums (as prescribed
by the manufacturer). No significant benefit of hydration solution was found
compared to placing flowers directly into a preservative solution. As expected,
use of a preservative solution increased longevity compared to water. - Roses and carnations were hydrated in 35 F
or 110 F
preservative solution. Results differed with cultivar but the
overall effect of water temperature was negligible. Madame Delbard
roses had the same longevity, degree of flower opening and leaf
quality. Water uptake was higher in flowers hydrated in warm water
but water uptake does not appear to be related to longevity or other
quality parameters. First Red rose lasted two days longer and flower
opening was enhanced when warm solution was used. No differences
were observed with water temperature and longevity or other quality
parameters (flower opening, leaf yellowing etc.) based on solution
temperature. - Cutting underwater or in air was evaluated on roses,
chrysanthemum, alstromeria and carnation. No differences between
type of cut and longevity in any crop evaluated. - Floral preservative (Floralife, Pokon and Chrysal) increased
flower longevity significantly for roses, carnations, chrysanthemum. Of all traditional
prophylaxes evaluated, use of a floral preservative had the greatest consistent
increase in longevity.
3. The effects of biocides, flower food, & ethylene
inhibition on a range of
individual crops.
During the past year we have studied the effects of ethylene, of vase
preservatives and of their components on a large number of traditional
and specialty cut flower crops. Some studies have been preliminary,
others have been more detailed. The details of our findings on the more
than 30 crops that we have studied can be browsed at our secure web-site
(http;//www.aes.ucdavis.edu/MReid.htm/(list flower name desired i.e.
amaryllis).
4.
Evaluation of hydration at farm level
Four cultivars of roses (Madame Delbard, First Red, Classy and Leonidas) were
hydrated for 2,4,6,12, 24 and 36 hours or not hydrated at production farms in
Columbia. Flowers were shipped to Gainesville, where they were hydrated or not
hydrated at 35 F for two days to simulate wholesaler conditions. Results varied
with cultivar, however, there did not appear to be an overwhelming positive
effect on longevity from increased farm level hydration. There was a trend
toward increased flower opening with increased hydration periods. The variation
may be due to the producers desire to use their own hydration solutions rather
than commercially available solutions. We are re-doing these studies with
Floralife and Pokon-Chrysal hydration solutions.
Some of the highlights of our findings include:
- The benefits of MCP in preventing ethylene effects in a range of
ethylene-sensitive flowers including: Carination, Larkspur,
Campanula, Asclepias, Anenome, Bouvardia, Dahlia, Lobelia, Lysimachia,
Stock, Oriental Lilies, Peony, Phlox, Veronica. - The dramatic effects of sugar (3-6%) on the opening, color, and
vase life of a range of flowers, including: Astilbe, Bouvardia,
Lisianthus, Liatris, Lysimachia, monte Casino Aster;
Solidaster, Veronica, Scahiosa, Picliscus, Nydrangea, Lobelia.
- The benefits of pulsing with a detergent solution to prevent
post-storage wilting in some crops, including sunflower, curcuma and
astilbe. - An unexpected ethylene response (at longer treatment times) by
flowers such as dahlia, sunflower, hydrangea, and celosia - The benefits of pulsing with high concentrations of sugar on the
opening and vase life of flowers such as lisianthus and tuberose - The benefits of a simple biocide, 50 ppm NaOCI, on the vase life of
a wide range of flowers, but damage for some (e.g. Asclepias, Celosia) - The benefits of a standard flower food for many (but not all) flowers The
high rate of water use by some foliage items (Bupleurum, Hypericum) - Miscellaneous corrections to current lore or literature, such as:
-Calcium does not improve the postharvest life of stock.
-STS does not prevent geotropic bending in snaps and bells of
Ireland.
-Water tubes are of little value in handling of dendrobium.
-STS is not a very useful pre-treatment for lisianthus (very
delayed benefit and not as useful as a sugar-containing vase
solution).
-STS is not a useful pre-treatment for godetia (retards flower
opening).
-Boiling the stem bases does not benefit the vase life of dahlia
or asclepias.
NEXT STEPS AND FUTURE FOR PROJECT AND ANTICIPATED INDUSTRY
BENEFIT(S).
Our immediate goal is to improve temperature management in cut flowers
shipped from California to wholesale florists across the United States.
Flowers will be shipped from California to the University of Florida for
longevity evaluations. Also, temperatures will be monitored in shipments
from Columbia to the University of Florida so these temperatures can be
compared and incorporated into the temperature model being developed by UC-Davis.
Further development of the temperature model is critical to increased
longevity of fresh flowers.
In concert with the CCFC we have instituted a pilot program called
“California Fresh” whose ultimate goal is to ensure that flowers are
maintained below 40 F from packing until they reach the wholesaler or retailer.
The proposed program has the enthusiastic support of shippers, truckers, and
major wholesalers, and will provide an excellent opportunity to determine the critical control points for maintaining low temperatures, and to provide focused
education on temperature management and packing for proper pre-cooling. The
industry as a whole will benefit as other parts of the industry implement
techniques that provide the consumer with flowers that have longer vase life and
therefore give more satisfaction.
Additional test will be conducted with duration and general conditions of
farm level hydration (Floralife and Pokon-Chrysal). The types of flowers for the
farm level tests and evaluation of traditional prophylaxes will be expanded to
include snapdragons, alstromeria, freesia and others of value interest to the
industry.
We propose to continue our studies of the use of MCP with
ethylene-sensitive crops, and to
extend our studies on primary determinants of vase life in a wide
range of species. We are
close to the point where we can publish (hopefully with support from
AFE) a workbook, possibly a revision of the SAF Care and Handling
manual, outlining key factors for improving the postharvest life of a
wide range of cut flowers that will update and extend previous
publications on topic.
