A Comprehensive Program in Increasing Post Production Longevity of Flowering Potted Plants Progress Report — June 2000
A COMPREHENSIVE PROGRAM FOR INCREASING POSTPRODUCTION
LONGEVITY OF FLOWERING POTTED PLANTS
Terril A. Nell, Ria T Leonard, James E. Barrett and David G.
Clark
Department of Environmental Horticulture,
University of Florida, Gainesville, PL 32611
INDUSTRY NEEDS AND PROJECT OBJECTIVES:
One of the major problems influencing potted plant longevity is the exposure
to ethylene. The presence of ethylene related symptoms following transport and
storage in an ethylene free environment, suggests that ethylene related injury
is a direct result of endogenous ethylene in the plant. Which plants susceptible
to endogenous ethylene are exposed to external ethylene in storage or display
conditions, the resulting injury may be worsened.
The objective of this project is to quantify the amount of exogenous ethylene
production in ten flowering potted plants and multiple cultivars of these crops,
to determine the role of endogenous ethylene in longevity and quality, and to
identify the effects of ethylene exposure on interior performance. In addition,
evaluating the use of the new commercially anti-ethylene compound l-MCP
(Ethyl-Bloc) will be tested. Understanding the role of endogenous ethylene and
its control will provide all segments of the industry with methods for extending
longevity and quality for the consumer.
SUMMARY OF WORK COMPLETED:
I. TESTING 110W LONG 1-MCP IS EFFECTIVE IN PREVENTING EXTERNAL ETHYLENE
INJURY
Potted kalanchoe, begonia cv. ‘AnneBelle’ and rose cv. ‘Charming Parade’
were treated with 1-MCP for 4 hours in a sealed chamber. Control plants were
treated with air. Plants were then placed in interior conditions maintained at
70F and 70 ftc. Over a time period of every 2 or 3 days, plants were placed in a
constant 1 ppm ethylene environment to determine how long 1-MCP is effective in
preventing ethylene injury symptoms.
KALANCHOL
Results indicate that 1-MCP is effective in delaying petal inrolling on
kalanchoe up to 7 days after treatment (Figure 1). Inrolling was delayed up
to 4 days on plants treated with 1-MCP. The control plants had an immediate
response to ethylene and the petals inrolled within 2 days. Treatment with 1-MCP
did not prevent inrolling, but did delay the response to this high dose of
ethylene.
BEGONIA
Results
indicate that 1-MCP reduced flower drop in begonia for a maximum of 2 days only
(Figure 2). This reduction was clear 1 day after 1-MCP treatment but then
results were variable. Variation could be due to the stage of the bud when
treated with 1-MCP as buds need to be at an advanced stage for 1-MCP to be
effective.
Figure 2. The effectiveness of 1-MCP on ‘Annebelle’ begonia.
The treatment of roses with 1-MCP prevented leaf drop for 5 days
(Table 1). By day 7, 90% of the leaves dropped within 3-4 days after exposure to
ethylene. Flower and buds appeared to be protected from a constant source of
ethylene only 3 days after treatment to 1 -MCP.
| Table 1. The effectiveness of 1-MCP on potted rose variety ‘Charming Parade’. |
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| Days after 1-MCP treatment |
Flower longevity (days) |
Bud longevity (days) |
Plant longevity (days) |
Leaf drop (%) |
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| Control | 1-MCP | Control | 1-MCP | Control | MCP | Control | MCP | |
| 0 (no ethylene) | 22 | 26 | 26 | 28 | 35 | 35 | <3% | <3% |
| 3 | 6 | 9.6 | 7.3 | 11 | 9 | 12.5 | 80% | <3% |
| 5 | 11 | 11 | 11 | 11 | 13 | 12.5 | 80% | <3% |
| 7 | 11 | 15 | 12 | 13 | 13 | 15.5 | 80% | 90% |
| 9 | 15 | 15 | 14 | 15 | 17 | 16 | 90% | 90% |
| 11 | 15 | 15 | 16 | 16 | 17 | 19 | 90% | 90% |
| 13 | 16 | 8 | 18 | 16 | 21 | 20 | 90% | 90% |
| Note: Flower and bud longevity based on date when placed into ethylene environment. |
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EXPERIMENTS IN PROGRESS:
We will be evaluating several varieties of kalanchoe, chrysanthemum, azalea,
Heimalis begonia, rose, hibiscus, cyclamen, gloxinia and poinsettia for
exogenous ethylene levels. Plants are placed in airtight containers for up to 72
hours in the dark and air samples are taken twice daily to measure the exogenous
ethylene levels. Plants are then evaluated in a simulated consumer environment
to determine what effects exogenous ethylene levels have on longevity and
quality.
FUTURE PLANS:
Our emphasis will be to 1) determine the effective period that Ethylbioc
protects flowering potted plants from ethylene; 2) determine the relationship
between endogenous ethylene production and injury typically associated with
ethylene. We will concentrate on potted rose, kalanchoe and rieger begonia
before expanding to other crops in the following year of this project. As
necessary, we will compare cultivar response to Ethylbioc and to endogenous
ethylene sensitivity. Following treatment, plants will be moved to a simulated
consumer environment for 30 days or until death. Plants will be evaluated for
flower longevity, flower, bud and/or leaf drop and overall quality.
ADDITIONAL BENEFITS
:
These evaluations will identify crops and varieties that are sensitive to
both endogenous and low external ethylene levels. This will provide needed
information on the ethylene sensitivity of many popular potted plant varieties.
Ideally, plant breeders will incorporate varieties with anti-ethylene
characteristics into ongoing breeding programs. Also, growers should eliminate
highly sensitive varieties from current production programs. These evaluations
will allow the industry to provide higher quality, longer-lasting flowering
potted plants to consumers. Results will also be published in trade magazines
and used in talks to the industry.
