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Current research in Current research in postharvest biology of postharvest biology of

ornamentals and cut flowersornamentals and cut flowers

CaiCai--ZhongZhong JiangJiang

USDAUSDA--ARSARS

Michael ReidMichael Reid

Department of Plant Sciences Department of Plant Sciences

UC DavisUC Davis

Value of California’s agricultureValue of California’s agriculture

2005 total $31.7 billion

Field crops,

$3.09

Greenhouse,

Nursery &

Floriculture,

$3.44

Vegetables &

melons, $6.25 Livestock &

poultry, $8.45

Fruits and nuts,

$10.47

Data from the California Department of Food and Agriculture.

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Source and sales of cut flowers in the Source and sales of cut flowers in the

U.S. during the last three decadesU.S. during the last three decades

The postharvest problemsThe postharvest problems

�� Flowers are shipped long Flowers are shipped long

distances and stored for long distances and stored for long

timestimes

�� >25% product losses in >25% product losses in

marketing chainmarketing chain

�� Flowers and potted plants don’t Flowers and potted plants don’t

last long enoughlast long enough

�� International market, strong International market, strong

competitioncompetition

�� Lower consumer satisfaction. Lower consumer satisfaction.

Customers don’t returnCustomers don’t return

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Postharvest sciencePostharvest science

�� Goal Goal -- reduce losses, reduce losses,

increase quality, expand increase quality, expand

markets markets

�� Understand factors Understand factors

involved in postharvest involved in postharvest

losseslosses

�� Develop better Develop better

technologies to reduce technologies to reduce

losses _ losses _ GeneticallyGenetically--improved cultivars improved cultivars

Factors affecting the postharvest Factors affecting the postharvest

life of ornamentalslife of ornamentals

��TemperatureTemperature�� DiseaseDisease

�� Water supplyWater supply

�� Leaf yellowing and Leaf yellowing and

flower senescenceflower senescence

�� EthyleneEthylene

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Temperature Temperature -- why is it important?why is it important?

�� Perishable products are alivePerishable products are alive

�� Flowers have high respiration ratesFlowers have high respiration rates�� Vase life after transit and storage is Vase life after transit and storage is

directly correlated with the respiration rate directly correlated with the respiration rate at the storage temperatureat the storage temperature

Improving the cold chainTransportation at low temperatures reduces respiration & improves the

subsequent life of cut flowers

3737 4141 46463232 5050 5555

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Temperature, respiration rate & Temperature, respiration rate & vase life in stock flowersvase life in stock flowers

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)

Re

sp

ira

tio

n (

ml

CO

2 /

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

Va

se

lif

e a

fte

r s

tora

ge

(d

ay

s)

Effects of different shipping Effects of different shipping

temperatures on potted temperatures on potted CampanulaCampanula

plant qualityplant quality

Effects of different shipping Effects of different shipping

temperatures on potted temperatures on potted CampanulaCampanula

plant qualityplant quality

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Effects of shipment temperature on flower senescence Effects of shipment temperature on flower senescence and bud abortion on potted and bud abortion on potted Campanula Campanula plantsplants

20 C Room 20 C

15C10 C

5 C0 C

Fresh flowers

Wilted flowers

Fresh buds

Aborted buds

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

Nu

mb

er

pe

r in

flo

resc

en

ce

Advantages of decreased Advantages of decreased

temperature in handling flowerstemperature in handling flowers

�� 11. respiration. respiration

2. transpiration2. transpiration

3. ethylene production3. ethylene production

4. ethylene susceptibility4. ethylene susceptibility

5. disease growth (5. disease growth (BotyrtisBotyrtis))

6. condensation6. condensation

7. need for wet holding /packing7. need for wet holding /packing

8. bending8. bending

9. flower development9. flower development

10. color loss/yellowing10. color loss/yellowing

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CoolingCooling

�� Forced air for cut Forced air for cut

flowersflowers

�� Potted plants could be Potted plants could be

vacuum cooledvacuum cooled

�� presently passive presently passive

cooling if at allcooling if at all

�� condensation!condensation!

Works wonderfullyWorks wonderfully

30

35

40

45

50

55

60

65

0 50 100 150

Downdraft cooling

Room cooling

Cooler temperature

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Vacuum cooling:Vacuum cooling:

a better approach to rapidly cool a better approach to rapidly cool

down potted plantsdown potted plants

The rapidity of vacuum coolingThe rapidity of vacuum cooling

in less than 10 minin less than 10 min

vacuum

Soil & stems

Flower buds

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Disease prevention Disease prevention

Postharvest disease (primarily Postharvest disease (primarily

caused by gray mold (caused by gray mold (Botrytis Botrytis

cinerea) cinerea) is a common cause of poor is a common cause of poor

quality and shortened vase lifequality and shortened vase life

Postharvest control strategiesPostharvest control strategies

Host

Environment

Pathogen

Disease life cycle The disease triangle

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EnvironmentEnvironmentGrey mold Grey mold –– moisturemoisture

watch watch for condensation (good for condensation (good temperature management)temperature management)

��Spores accumulate on:Spores accumulate on:

�� Dead plant materialsDead plant materials

�� Cooler Cooler wallswalls

Genetic difference of disease Genetic difference of disease

resistance among rose genotypesresistance among rose genotypes

0

2

4

6

8

10

12

14

16

18

20

Bri

da

l A

kit

o

43

72

33

35

34

19

45

26

Ve

nd

ela

45

13

40

40

43

97

Blu

sh

ing

Ak

ito

40

29

Da

rk E

ng

ag

em

en

t

33

58

30

26

33

78

44

10

Variety/code

Tim

e t

o in

fec

tio

n (

da

ys

)

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�� Commercial / Industry SanitizersCommercial / Industry Sanitizers

�� Plant Defense CompoundsPlant Defense Compounds

�� FDA GRAS/GRASE DesignationsFDA GRAS/GRASE Designations

�� Alternative uses for existing productsAlternative uses for existing products

‘Orlando’ rose flowers were dipped in 0 or 10 ppm Cl02

then shipped to Florida within 3 days. Vase life evaluationshowed a significant reduction in Botrytis infectioncompared to non-dipped flowers.

?Time (days)

0 2 4 6 8 10 12

Dis

ea

se

in

cid

en

ce

(% o

f fl

ow

ers

in

fec

ted

)

0

20

40

60

80

100 No chlorine dioxide dip

Plus chlorine dioxide dip

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�� Effective as a dip treatmentEffective as a dip treatment

�� 1 1 -- 6% solution6% solution

�� PhytotoxicityPhytotoxicity

Using NaOCl to control Botrytis infection in cut roseUsing NaOCl to control Botrytis infection in cut rose

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Effects of Effects of NaOClNaOCl treatment on Botrytis treatment on Botrytis

incidences during rose shippingincidences during rose shipping

Incidence (Akito)

0

20

40

60

80

100

No Dip H2O Dip Phyton 27 NaOCl

Treatments

Day 4

Day 7

Gold Strike

0.0

20.0

40.0

60.0

80.0

100.0

No Dip H2O Dip Phyton 27 NaOCl

Tre atments

Day 4

Day 7

Water supplyWater supply

�� Plants are mostly Plants are mostly

water (80water (80--90%)90%)

�� Loss of water causesLoss of water causes

�� loss of qualityloss of quality

�� wiltingwilting

�� accelerated agingaccelerated aging

�� (ethylene production)(ethylene production)

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Water supplyWater supply

�� How do plants get water?How do plants get water?

�� Evaporation from leaves Evaporation from leaves

(transpiration) creates (transpiration) creates

tension in the conducting tension in the conducting

system (xylem)system (xylem)

�� Tension drags water from Tension drags water from

the soil or vase solutionthe soil or vase solution

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Water supplyWater supply

�� Why do cut flowers wilt?Why do cut flowers wilt?

�� Air embolismAir embolism

�� Bacterial contaminationBacterial contamination

�� Why do potted plants wilt?Why do potted plants wilt?

�� DroughtDrought

�� WaterloggingWaterlogging

Air embolism blocks vesselsAir embolism blocks vessels

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Maintaining water supplyMaintaining water supply

�� FlowersFlowers

�� recut under waterrecut under water

�� use a preservativeuse a preservative

�� clean bucketsclean buckets

�� Potted plantsPotted plants

�� good mediumgood medium

�� water as neededwater as needed

�� allow to drainallow to drain

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An Alternative Postharvest Handling An Alternative Postharvest Handling Strategy for Cut Flowers Strategy for Cut Flowers ––Dry Handling after HarvestDry Handling after Harvest

0

5

10

15

20

25

Black Magic Charlotte Freedom Osiana Vendela

No hydration

Plus Hydration

Application of ABA enhances display Application of ABA enhances display

life of potted miniature rose plantslife of potted miniature rose plants

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0

2

4

6

8

10

12

14

16

18

0 10 20 50

Dis

pla

y l

ife (

days)

ABA concentration (ppm)

b

a aa

ABA treatments enhance display life of ABA treatments enhance display life of potted miniature rose plantspotted miniature rose plants

Application of ABA reduces Weight loss Application of ABA reduces Weight loss

from potted miniature rose plantsfrom potted miniature rose plants

20

30

40

50

60

70

80

90

100

0 5 10 15 20

We

igh

t lo

ss

(%

of d

ay 0

)

Time (days)

0ppm10ppm20ppm50ppm

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Leaf yellowingLeaf yellowing

��For many ornamentals, leaf For many ornamentals, leaf yellowing during and after yellowing during and after production is a serious production is a serious quality issuequality issue

��Depending on the species, Depending on the species, this problem can be this problem can be overcome by application of overcome by application of the plant growth regulators, the plant growth regulators, GA, BA, or a mixture of the GA, BA, or a mixture of the two (recently registered as two (recently registered as ‘Fascination’)‘Fascination’)

Thidiazuron (TDZ)Thidiazuron (TDZ)

�� Also known as PhenylAlso known as Phenyl--N'N'--(1,2,3(1,2,3--

thiadiazolthiadiazol--55--yl) urea. yl) urea.

�� Has strong Has strong cytokinincytokinin activity.activity.

�� Used as a growth regulator in Used as a growth regulator in

tissue culturetissue culture

�� Used as a cotton defoliant Used as a cotton defoliant

((DroppDropp))

�� Is not metabolized, so remains Is not metabolized, so remains

activeactive

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Growth regulators delay leaf Growth regulators delay leaf

yellowingyellowing

��TDZ (thidiazuron), a TDZ (thidiazuron), a nonnon--metabolized metabolized cytokinincytokinin

Effect of TDZ on leaf yellowing, flower Effect of TDZ on leaf yellowing, flower

opening and longevity in iris opening and longevity in iris

0 µM TDZ 500 µM TDZ0 µM TDZ 500 µM TDZ

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TDZ treatment after 30 days

Control after 30 days

Effects of TDZ on the leaves of Ornithogalum

ControlControlTDZ TDZ

Effects of TDZ on CyclamenEffects of TDZ on Cyclamen

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EthyleneEthylene

�� Some flowers and plants are very Some flowers and plants are very

sensitive to ethylene (0.1 ppm)sensitive to ethylene (0.1 ppm)

�� Ethylene is everywhereEthylene is everywhere

�� engines, ripening fruit, cigarette smokeengines, ripening fruit, cigarette smoke

�� Shouldn’t be a problemShouldn’t be a problem

�� STS, 1STS, 1--MCPMCP

Techniques for inhibiting Techniques for inhibiting

ethylene actionethylene action

�� Controlled atmospheresControlled atmospheres

�� Low oxygen, high COLow oxygen, high CO22 inhibit production, actioninhibit production, action

�� ChemicalsChemicals--STS STS

�� complex salt of silver nitrate, sodium thiosulfatecomplex salt of silver nitrate, sodium thiosulfate

�� used commercially with cut flowers, potted used commercially with cut flowers, potted

plantsplants

�� environmental issues environmental issues -- silver a heavy metalsilver a heavy metal

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STS STS

MCP provides valuable MCP provides valuable

protection for ornamentalsprotection for ornamentals

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Avoiding ethylene effects: cultivar Avoiding ethylene effects: cultivar

selection/engineeringselection/engineering

�� Choose insensitive cultivarsChoose insensitive cultivars

�� Snapdragons, Carnations, RosesSnapdragons, Carnations, Roses

�� Modulate ethylene's roleModulate ethylene's role

�� AntiAnti--sense ACC synthasesense ACC synthase

�� Etr mutants, antiEtr mutants, anti--sense binding sitesense binding site

Ethylene BiosynthesisEthylene Biosynthesis

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Example: Silencing a gene required for ethylene synthesis in petunias (ACC oxidase)

ControlTRV PhCHSTRV PhCHS/ACOTRV PhCHS/ACO

Day 0

Day 7

Day 3

Ethylene biosynthesis and sensing/signalingEthylene biosynthesis and sensing/signaling

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Overexpression of Overexpression of etr1etr1--1 1 byby inducible inducible

systemsystem extends flower longevityextends flower longevity

Overexpression of Overexpression of etr1etr1--1 1 byby inducible inducible

systemsystem extends flower longevityextends flower longevity

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AcknowledgmentsAcknowledgments

�� USDAUSDA�� BARD_IsraelBARD_Israel�� American Floral American Floral

EndowmentEndowment�� Joseph H. Hill Joseph H. Hill

Memorial FoundationMemorial Foundation�� MellanoMellano & Company& Company�� KitayamaKitayama BrothersBrothers�� Goldsmith SeedsGoldsmith Seeds�� Rosen Rosen TantauTantau