3. Ethylene
• Ethylene is a natural plant hormone released in the form of a
gas.
• It triggers cells to degrade, fruit to turn softer and sweeter,
leaves to droop, and seeds or buds to sprout.
• While some fruits and vegetables are high ethylene
producers, others are more sensitive to it.
4. Discovery
• Doubt discovered that ethylene stimulated abscission in 1917
(Doubt, 1917).
• Gane reported that plants synthesize ethylene (Gane, 1934).
• In 1935, Crocker proposed that ethylene was the plant
hormone responsible for fruit ripening as well as inhibition of
vegetative tissues (Crocker, 1935).
6. • The simplest of the organic compounds known as alkenes,
which contain carbon-carbon double bonds.
• It is a colourless, flammable gas having a sweet taste and
odour.
• Natural sources of ethylene include both natural gas and
petroleum; it is also a naturally occurring hormone in plants,
in which it inhibits growth and promotes leaf fall.
7. Role of ethylene
• Much of this production goes toward polyethylene, a widely
used plastic containing polymer chains of ethylene units in
various chain lengths.
• Ethylene is also an important natural plant hormone, and is
used in agriculture to force the ripening of fruits.
• Ethylene's hydrate is ethanol.
8. Ethylene and vegetables
• Ethylene gas is used commercially to ripen tomatoes,
bananas, pears, and a few other fruits postharvest.
• Ethylene can be explosive if it reaches high
concentrations, so it has to be used cautiously.
• only used preharvest.
• There are three main ways to produce ethylene:
• gas from a cylinder
• catalytic generator
• ethephon.
9. • Ethylene, also known as the ‘death or ripening hormone’ plays
a regulatory role in many processes of plant growth,
development and eventually death.
• Industries that are involved in handling and storage of fruits
and vegetables are severely affected monetarily by ethylene.
• High concentration of ethylene causes premature aging and
rotting of fruits and vegetables.
• thus lowering its shelf life.
10. Effects
• The overall effect of Ethylene is to hasten ripening, aging and
eventually spoilage.
• Cabbage
11. • Ethylene effects include
• fruit ripening.
• loss of chlorophyll.
• abortion of plant parts.
• stem shortening.
• abscission of plant parts.
• epinasty (bending of stems).
12. • There are several ways to measure ethylene:
• 1) gas chromatography (best but expensive)
• 2) kitagawa tubes, or equivalent.
• 3) other types of chemical sensors.
• 4) another plant that is sensitive to ethylene.
