A Comprehensive Program in Increasing Progress Reports - June 2000
A PROGRAM FOR INCREASING POSTPRODUCTION - June 1, 2000
A COMPREHENSIVE PROGRAM FOR INCREASING POSTPRODUCTION
LONGEVITY OF FLOWERING POTTED PLANTS
Terril A. Nell, Ria T Leonard, James F. Barrett and David G.
Clark
Department of Environmental Horticulture
University of Florida,
Gainesville, FL 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. When 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 tell flowering p tied
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 1 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 HOW LONG 1-MCP IS EFFECTIVE IN PREVENTING EXTERNAL ETHYLENE
INJURY
Potted kalanchue, 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.
KALANCHOE
Resulis 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.
The effectiveness on 1-MCP on kalanchoe.
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.
The effectiveness of 1-MCP on ‘Annebelle’ Begonia.
ROSES
The treatment of roses with 1-MCP prevented leaf drop for 5 das (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’, |
||||||||
| Days after 1-MCP Treatment |
Flower longevity (days) |
Bud longevity (days) |
Plant longevity (days) |
Leaf drop (%) |
||||
| Control | 1-MCP | Control | 1-MCP | Control | MCP | Control | MCP | |
| 0 | 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% |
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 Ethylbloc
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 Ethylbloc 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.
