Download Ozone and the Shelf Life of Cut Roses: Test

Ozone and the Shelf Life of Cut
Roses: Test Tubes to Trials
Stacey Robinson*, Youbin Zheng, Michael Dixon
Controlled Environment Systems Research Facility (CESRF)
Department of Environmental Biology, University of Guelph, Guelph,
Ontario, Canada N1G 2W1
Agenda
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Rose Stats
Bacteria Problem
Current Antibacterials & Ozone as a Solution
Experimental Setup
Results
Significance of Research
Future Research
• Acknowledgements
Rose Stats
• Canadian floriculture sales in 2002 were
CDN $1.42 billion; roses were the #1 cut
flower sold
• Premature wilting of cut roses results in an
economic loss for growers; on average
about 20%, but up to 50%
Bacteria Problems
• Shelf-life of cut roses is directly related to water
uptake
• Addition of antibacterial compounds to cut rose
storage water increases water uptake,
enhancing shelf-life
Bacteria
Water
Uptake
Value of
Rose Crop
Current Antibacterials
• In the cut rose industry, a lot of money is spent
on antibacterials that have limited effectiveness
Antimicrobial Agent
HQC
Chlorine
Acid
Sugars
Problem
Expensive, Resistance
Toxicity
Expensive, Moulds,
Toxicity
Provides bacteria with C
Ozone: An Ideal Candidate
• Less expensive than current antibacterials
• Safer for both roses and workers
• More effective
My Research
To determine the efficacy of aqueous ozone
at increasing the shelf-life of cut roses
Experimental Setup
Central Purification System
Experimental Setup, cont’d
Controlled Climate Chamber
Results
Aesthetic Appearance
Day 5 - Deionized Water
Day 5 - Ozonated Water
Bacteria Problems, cont’d
Cut Rose End in
Deionized Water
Cut Rose End in
Ozonated Water
Shelf-life
14
Shelf-life (days)
12
13.0
10
8
6
4
2
5.0
0
Deionized Water
Ozonated Water
Criteria: Development of bent neck, petal/leaf discolouration,
petal/leaf wilting, petal/leaf abscission
Bacteria & Rose Health
Shelf-life
Water Uptake
Total Water Uptake (mL)
Shelf-life (days)
12.5
10.0
7.5
5.0
2.5
0.0
0
1
2
3
4
Log CFU/mL
n = 5, P < 0.0001
5
6
7
200
100
0
0
1
2
3
4
Log CFU/mL
5
6
7
Ozonated Water
6
(Log10 CFU/mL)
Number of Bacteria
Bacteria in storage water
Deionized Water
5
4
3
2
1
0
1
3
5
7
9
Time (days)
11
13
Rate of Acid Fuchsin
Uptake (cm/min)
Acid Fuchsin Dye Uptake
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
4.0
1.7
Deionized Water
n = 10, P < 0.0001
Ozonated Water
Acid Fuchsin, cont’d
% Functional Vascular Bundles
Deionized Water
100
75
91%
50
Ozonated Water
25
1.2%
0
Deionized Water
n = 10, P < 0.0001
Ozonated Water
Relative Water Content (%)
Relative Water Content
100
90
80
92.4%
85.0%
Deionized Water
n = 10, P < 0.0001
Ozonated Water
Evaluating Ozone
• Ozone, from 1.0 to 5.5 ppm, was effective at
reducing the bacterial load in rose storage water
• Roses treated with ozone had
three times longer shelf-life
• No sign of toxicity to ozone was seen
at concentrations up to 5.5 ppm
Where are we now?
Significance of Research
• Provides growers with an antibacterial agent that
is:
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Effective
Safe for workers
Non-toxic to roses
Economical
• Growers experience less product loss
• Consumers are provided with longer lasting
roses
Significance of Research, cont’d
• Once an ozone systems is set up in the
greenhouse, it can be used for other
applications such as:
– Surface sterilization
– Recirculating nutrient solutions
– Water treatment
– Likely applicable to other plant species
What Now?
Investigate the mechanism by which
bacteria reduce water uptake and shorten
cut rose shelf-life
??
Acknowledgements
• University of Guelph
– Dr. Mike Dixon
– Dr. Youbin Zheng
– Tom Graham
• Centre for Research in Earth & Space Technology
• Purification Research Technologies Inc. (PRTI)
• Thiessen Greenhouses Inc.
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