Ornamentals Flashcards

1
Q

Cut flowers end of vase life

A
Senescence
• Botrytis
• Bent neck / stem break
• Flower/leaf wilting
• Turbid and smelly water
• Leaf yellowing / blackening
• Stem blackness
• Petal discoloration
• Flower disc discoloration
• Impaired flower opening
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2
Q

Potted plants end of shelf life

A
Flower senescence / flower drop
• Leaf drop
• Leaf discoloration
• Chilling injury
• Ethylene effect
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3
Q

• Cuttings quality problems

A
  • Bad rooting
  • Wilting
  • No shooting
  • Wound response
  • Ethylene and other hormones
  • Plant physiological processes
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4
Q

What causes turbid water?

A
  • bacteria - botrytis
  • disbudded flower : there is abundance of sugar so the bacteria can grow better -> more turbid water and also faster than spray flower(low shelf life)
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5
Q

Ideal cut height of flowers for better vase life

A

> 25 cm cut above the soil -> increase the fresh weight during vase life

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6
Q

Carbohydrate leakage

What happens when you increase storage of cut flowers?

A
  • increase storage sugar in the stems -> with chilling injuries (low T) membranes break -> increase the sugar in the water -> bacteria growth in the vase (turbid water)
  • disbudded flower have higher amount of sugars compared to spray flower so they have less carbohydrate starvation therefore extended vase life
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7
Q

Hormones. How do they affect postharvest life of flowers

A
  • Cytokinin improves potted cyclamen -> reverse senescence -> makes juvenile tissues again
  • ABA improves desiccation in miniature roses
  • ethylene leads to flower drop
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8
Q

Disease / pest

A
  • Botrytis on cut flowers

* Powdery Mildew etc. etc

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9
Q

How water uptake blockage can happen?

A
  • bacterial blockage
  • air emboli
  • enzymatic wound response
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10
Q

Bad water balance -> end of vase life (stem break)

A

Fresh weight -> quality assesment

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11
Q

Solutions to deteriorate water balance

A
• Cut of the infected part
  Can only move up the stem up to the pith 
  membrane
• Use biocides (and clean water)
   Bleach, DICA, HQS, Al2(SO4)3
• Keep everything cold
   Bacteria grow slower at low temp
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12
Q

Solutions to deteriorate air emboli

* it is caused by air shoots in xylem vessels and by negative pressure

A
  • Cold water lowers change for air emboli
  • Solubility of air is higher in cold water
  • Detergent to lower surface tension
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13
Q

PAL enzyme inhibitor

A
Stress response can lead to blockages
• Inhibiting stress enzyme such as PAL reduces
blockage
• Cut and recut as little as possible
• Low temperatures reduce wound
response
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14
Q

What happens with high relative humidity ?

A

1) -saves energy
- reduced keeping quality
2) stomata mulfunctioning they lose the ability to close if they have a long exposure to high RH which leads to a negative water balance and early end of vase life

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15
Q

Why do we add Postharvest additives immediately after harvest ?

A
  • Decrease bacteria
  • Avoid air emboli
  • Suppress wound response
  • Prevent carbohydrate starvation
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