postharvest short course 2014 ornamentals part1 · daylily, tulips, iris, freesias, daffodils...

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Cai‐Zhong Jiang, USDA‐ARS, DavisMichael Reid, University of California, Davis

• Floriculture crops :

cut flowers, cut cultivated greens, foliage plants, potted flowering plants, annual bedding/garden plants, propagative floriculture materials

• Nursery crops : 

Evergreens_broadleaf, Trees_shade, flowering, Christmas trees, fruit and nut plants, transplants, shrubs and other ornamentals and propagation materials

Ornamental Industry

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Value of California’s agriculture

Data from the California Department of Food and Agriculture.

The postharvest problems

• Flowers are shipped long distances and stored for long times

• >25% product losses in marketing chain

• Flowers and potted plants don’t last long enough

• International market, strong competition

• Lower consumer satisfaction. Customers don’t return

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Postharvest science

• Goal ‐ reduce losses, increase quality, expand markets 

• Understand factors involved in postharvest losses

• Develop better technologies to reduce losses 

• Temperature• Disease• Water supply• Ethylene• Food supply

Factors affecting the postharvest life of ornamentals

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Temperature ‐ why is it important?

• Perishable products are alive

• Flowers have high respiration rates

• Vase life is directly correlated with the respiration rate

y = 0.0012x4 - 0.0619x3 + 1.2003x2 - 3.6913x + 25.509

R2 = 0.9974

0

50

100

150

200

250

300

350

0.0 5.0 10.0 15.0 20.0 25.0 30.0

Temperature (C)

Res

pir

atio

n(m

lC

O2

/kg

hr) y = -0.0299x + 7.1564

R2 = 0.9426

0

1

2

3

4

5

6

7

8

9

0 50 100 150 200 250

Total CO2 respired during storage (x100) ml CO2/kg

Vas

e lif

e af

ter

sto

rag

e (d

ays)

Temperature, respiration rate & vase life in stock flowers

Example ‐ Carnations

• Last for five days at 20 C• Q10= 4• Life = 20 days at 10 C• Life = 80 days at 0 C• We can store carnations for 10 weeks

Tulips after dry storage at different temperature

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Snapdragon after dry storage at different temperature

Effect of temperatureLilies stored 5 days, 2 days in vase life room

2.52.5 55 7.57.500 1010 12.512.5 1515

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Improving the cold chainTransportation at low temperatures reduces respiration & 

improves the subsequent life of cut flowers

3737 4141 46463232 5050 5555

Advantages of decreased temperature in handling flowers

1. respiration2. transpiration

3. dehydration4. ethylene production5. ethylene susceptibility6. condensation

7. disease growth (Botrytis)8. bending9. flower development10. color loss/yellowing

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Postharvest Disease

Postharvest disease (primarily caused by gray mold (Botrytis cinerea) is a common cause of poor quality and shortened vase 

life

Botrytis cinerea

Ubiquitous and necrotrophic fungus

Affects numerous agricultural crops

Causal agent of gray mold disease

Brings about severe economic losses

Pre‐harvest  and postharvest infection

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Disease control strategies

Host

Environment

Pathogen

The disease life cycle

The disease triangle

Disease

Disease control

Reduce spore load

o sanitation in field, greenhouse, shed

Prevent spore germination

o reduce condensation, injury, temperature

Prevent fungal entry

o care in handling

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Disease control Temperature

Humidity 

o prevent condensation

Atmosphere 

o high CO2, CO/low O2

Fungicides

Rely on synthetic chemical fungicides

Effective Applied by dipping, in fogs Development of resistance Safety & environmental 

concerns

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Alternative or Non‐Conventional  Chemical Control

• Active ingredient in household bleach

• A strong oxidizing agent with broad spectrum antimicrobial activity

• Commonly used for reducing bacterial and fungal contamination on fruit and vegetable surfaces and in flower vase solutions 

Sodium hypochlorite (NaOCl)

Optimal concentration of sodium hypochlorite for controlling botrytis on rose ‘Akito’ and ‘Gold Strike’ 

flowers

No dip 0 100 200 400 800

Bo

tryt

is in

cid

en

ce (

%)

0

20

40

60

80

100 'Akito' 'Gold Strike'

NaOCl concentration (µL L-1)

aa

a

a

b

bb

bb

b b b

Flowers were dipped in 0, 100, 200, 400 or 800 µL L‐1 (ppm) NaOCl (provided by Clorox® Ultra bleach solution) for 10 s. 

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Optimal treatment time of sodium hypochlorite for controlling botrytis on rose ‘Gold Strike’ flowers

Dip treatment time (s)

0 1 5 10 30

Bot

rytis

inci

denc

e (%

)

0

20

40

60

80

100 Water NaOCl

aa

a

a

aa

b b b b

Flowers were dipped in 0 (water) or 200 µL L‐1 (ppm) NaOCl (provided by Clorox®

Ultra bleach solution) for 1, 5, 10 or 30 s at 20°C.

Using NaOCl to control Botrytis infection in cut rose

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Water supply

• Plants are mostly water (80‐90%)

• Loss of water causes

– loss of quality

– wilting

– accelerated aging

– (ethylene production)

Water supply

• How do plants get water?

• Evaporation from leaves (transpiration) creates tension in the conducting system (xylem)

• Tension drags water from the soil or vase solution

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Water supply

• Why do cut flowers wilt?– Air embolism

– Bacterial contamination

• Why do potted plants wilt?– Drought

– Waterlogging

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Air embolism blocks vessels

• Recut under water• Acidify the water• Use warm (or cold) water• Pressurize (20 cm H2O)• Use a brief detergent dip

• Recut under water• Acidify the water• Use warm (or cold) water• Pressurize (20 cm H2O)• Use a brief detergent dip

Minimizing Air emboli

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• Use a preservative• Clean white buckets• Use a preservative• Clean white buckets

Maintaining water supply

No ClO2 Plus ClO2

The simple question:Would you drink that water, from that bucket?

The simple question:Would you drink that water, from that bucket?

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Ethylene dependent Ethylene production prior to onset of

natural senescence

Pollination accelerates ethylene production and senescence

Carnation, roses, snapdragon,

Ethylene independent flowers: Low or no ethylene production Pollination has no effect on longevityEthylene inhibitors do not extend lifeShort‐lived and important crops 

Daylily, Tulips, Iris, Freesias, Daffodils

Response to ethylene treatments

Rose plants were initially stored at 0C for 7 days and then treated with 2.5 ppm of ethylene for 48 hours.

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STS 

Benefits of 1‐MCP

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• The mutant receptor, etr1-1, identified from Arabidopsis has been shown to be unable to bind ethylene and confers ethylene insensitivity.

• Expression of Arabidopsis etr1-1 in other species, including carnation, leads to delayed floral senescence.

Using biotechnology to block ethylene signaling

Food

• Flowers need food to grow and develop

• Sugar (sucrose, glucose, or fructose) provides all that is needed

• Vase solutions should contain 1.5 – 3% sugar

• Bacteria like sugar too – use a bactericide

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Food

Sugar pulsing to provide food

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• Temperature• Disease

• Water supply

• Ethylene

• Food supply

Factors affecting the postharvest life of ornamentals