Using Ethylene to Help “Increase� Cut Flower Longevity and Sales (Also Applicable for Potted and Bedding Plants) George Staby, Ph.D. Perishables Research Organization (PRO) Florence, AZ and Elk Grove, CA
Introduction PRO Institutes are intensive 2.5-day workshops that address various floral postharvest care, handling, and marketing topics. Thirty-eight individuals representing 24 companies and 2 universities* recently attended the 15th PRO Institute held on the University of California, Davis campus. The information presented below is a direct result of this workshop. Fact one: Numerous past and present consumer studies have shown that inadequate cut flower longevity is a key factor negatively affecting consumer flower purchases in the US and Canada. Fact two: Ethylene is a gas that can promote premature flower death, petal fall, leaf fall, and/or abnormal flower opening among other negative traits. An estimated 41% of cut flowers grown for US and Canadian markets can be damaged by ethylene. Fact three: As bad as ethylene-induced damages are, they are nearly 100% preventable either by growing flowers that are insensitive to ethylene or by properly treating ethylene sensitive flowers with anti-ethylene products containing 1-methylcyclopropene (MCP) or silver thiosulfate (STS). MCP is sold as EthylBloc and Ethylene Buster whereas STS is sold as AVB, EthylGuard, and Florissima 125.
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Ethylene test for flowers
Fact four: There is no comprehensive list of cut flower species and cultivars based on ethylene sensitivity. Fact five: A simple and inexpensive test can be used to determine if flowers are ethylene sensitive and/or if they have been properly treated with STS or MCP. This test uses a product called Florel, which is a liquid that releases ethylene gas when applied to flowers and leaves. Named the “Florel Test”, it is now described.
Florel Test Directions Florel can be purchased from many sources including www.amazon.com and http://www.montereylawngarden.com/. One pint (500 ml) costs about $18-22 plus shipping and will last for about 50 tests. Make a 1% solution of Florel in a spray bottle by adding 10 milliliters (1/3 fluid ounce) of Florel to one liter (quart) of water - or proportional amounts if more or less spray volume is needed. Recut the stems of 5-10 flowers of the same cultivar you want to test, place into a vase of flower food solution, and spray the flowers and leaves to runoff with the 1% Florel solution. Label this vase “plus ethylene”. Place an equal number of recut flowers of the same cultivar from the same bunch or bunches in a second vase of flower food solution but do not spray them. Label this vase “no ethylene”. Place the vases about two feet apart in a room at 65-75 F (no direct sunlight) and observe them over 3-5 days.
Possible Test Results If flowers in both vases look the same during the 3-5 days, the flowers are not sensitive to ethylene and/or were properly treated with either STS or MCP. If ethylene treated (1% Florel sprayed) flowers show damage and start to die faster than the non-sprayed ones, the flowers are ethylene sensitive (see example in Figure 1). If ethylene treated (1% Florel sprayed) flowers show damage and start to die faster than those treated with MCP or STS before being exposed to ethylene, the flowers are ethylene sensitive but were properly treated with MCP or STS (see example in Figure 2). If flowers in both vases die prematurely, they are bad flowers for unknown reasons and therefore the test is invalid and needs to be repeated.
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Ethylene test for flowers Additional Comments
Some cultivars of the same flower can be ethylene sensitive while other cultivars are not. Using data generated at the University of Florida as an example, rose cultivars that are ethylene sensitive include ‘Freedom’, ‘Osiana’ and ‘Vendela’, while ethylene insensitive cultivars include ‘Forever Young’, ‘Cool Water’ and ‘Gold Strike’. Testing ethylene sensitivities of bouquets can present challenges because there may not be sufficient flowers of the same cultivar in a bouquet to properly run the Florel Test. While this does not present a problem for the bouquet makers because they can test the flowers before the bouquets are made, it does present a problem for bouquet receivers. Thus, receivers of bouquets should compare 3-4 bouquets sprayed with 1% Florel against 3-4 bouquets not sprayed. Potted and bedding plants can also be tested in a similar fashion (see examples in Figures 3 & 4). However, only MCP can be used to treat potted and bedding plants, not STS.
Who should routinely use the Florel Test? Breeders should use ethylene sensitivity in their selection process, just like selecting for other factors such as production time, flower color, and stem length. Growers can determine which flowers they grow are ethylene sensitive and thereby treat the sensitive ones with STS or MCP or discontinue growing them. Growers can also use the Florel Test to determine if they should grow a new cultivar. Namely, if the new cultivar is ethylene sensitive, then they should consider not growing it. Large wholesalers and retailers hold the key as to whether or not the floral industry will eventually grow and sell mainly ethylene insensitive flowers by using the Florel Test as an objective quality control tool to accept or reject incoming bunches and bouquets. The Challenge and Opportunity Is your company willing to take up the “challenge” to routinely use the Florel Test to help determine which flowers and plants to introduce, grow, buy, and/or sell? By doing so, you have an “opportunity” to reduce shrinkage, enhance profits, increase display life, and improve flower and plant longevity for consumers. Questions, Comments, and/or Additional Information? Contact the author at georgestaby@chainoflifenetwork.org or 520-723-9705. Additional floral postharvest and marketing information can be obtained at http://www.chainoflifenetwork.org/.
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Ethylene test for flowers
__________ * The following companies and universities were represented at the PRO Institute: Bloomtime Flowers, C. H. Robinson, Chrysal Americas, Ethylene Control, Felix Instruments, Field of Flowers, FloraFresh, Floralife, Flores Funza, Green Valley Floral, ICA TriNova LLC, Johnson Pacific Design, Joseph & Sons, Kendal Floral, Kitayama Brothers, KJL Associates, Mellano & Company, Raley’s Supermarkets, Riverdale Farms, Save Mart Supermarkets, Sensitech, Sunshine Bouquet, Syndicate Sales, The Sun Valley Group, and the Universities of California and Florida.
Figure 1. The ‘Osiana’ roses on the right show ethylene-induced damage (petal fall) after being ethylene treated while the ones on the left were not ethylene treated. Thus, the rose cultivar ‘Osiana’ is ethylene sensitive. Photo courtesy of Dr. Andrew Macnish.
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Ethylene test for flowers
Figure 2. Both of the ‘Charlotte’ roses were treated with ethylene but he one on the left was first treated with STS. The rose on the right shows ethylene-induced damage (poor opening and discoloration), while the one on the left was protected from ethylene by STS. Thus, the rose cultivar ‘Charlotte’ is ethylene sensitive and STS worked in preventing ethylene-induced damages. Similar results would have been obtained if MCP was used instead of STS. Photo courtesy of Dr. Anil Ranwala.
Figure 3. The right half of a ‘Super Elfin Bright Orange’ Impatiens plant was sprayed with Florel resulting in flower fall in less than 24 hours. Hence, this Impatiens cultivar is ethylene sensitive. Photo courtesy of Dr. Peter Konjoian.
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Ethylene test for flowers
Figure 4. Torenia ‘Clown Blue’ plant on left was not treated with ethylene or MCP, middle plant was first treated with MCP (MCP sachet in shipping box) and then ethylene, plant on right was treated only with ethylene. Hence, this cultivar is ethylene sensitive as noted by the flower fall in the ethylene treated plant (on right) but MCP prevented ethylene from promoting flower fall (middle plant). Photo courtesy of Dr. Michelle Jones.
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