2. INTRODUCTION
• It is the gaseous hormone.
• Represented as CH2=CH2.
• It is produced in minute quantities by plant tissues
and active at extremely low concentrations.
• Not easily soluble in aqueous medium.
• Meristems and nodes are the chief sites for the
production of ethylene.
3. • Ethylene synthesis is particularly strong
during:
• Ripening of fruits
• Leaf fall
• Senescence of flower
• Injuries
• Drought stress, etc.
4. PHYSIOLOGICAL EFFECTS OF
ETHYLENE
• Induction of ripening in fruits
• Induction of epinasty
• Inhibition of elongation growth in stems and
roots
• Stimulation of cells to grow isodimetrically
rather than longitudinally-thus enhancing
radial growth.
• Stimulation of seed germination in some
species.
5. • Induction of root hair formation
• Promotion of leaf abscission
• Induction of flowering in pineapples
• Induction of fading in pollinated orchids
• Induction of basipetal polar and lateral
transport of auxins
• Regulation of levels of auxin.
6. Ethylene
• Agricultural Uses
– Ethaphon - breaks down to form ethylene
• 1. Fruit Ripening
Tomato, Banana, Melon, etc.
Pick unripe and firm for shipping
Spray in store to "ripen"
Color development and softening
Field Spray
Uniform and synchronous ripening
Canning Tomatoes
Mechanical Harvest
7. Ethylene
• 2. Floral Development
Bromeliads
Pineapple
Banana
Uniform development of inflorescence
• 3. Sex Expression
Female Flowers
Curcubits
opposite of GA action
• 4. Degreening of Citrus
Oranges, Lemons, Grapefruit
Break down Chlorophyll
Leaves Carotenoids
8. Ethylene
• 5. Mechanical Harvesting
Formation of Abscission Zone
Stimulate Fruit Drop
Cherries, Walnuts, Pecans
• 6. Postharvest Shelf Life
block ethylene synthesis
AgNO3 or Silver Thiosulfate
delay senescence
Carnations
