Plant Hormones - Ethylene

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Plant Hormones - Ethylene

• Found in
• Tissues of ripening fruit
• Nodes of stems
• Aging leaves and flowers
• Major functions
• Changes of ovary to become fruit
• Degradation of cell walls softening
• Dropping from plant
• Leaf abscission
• Loss of leaves to prevent water loss
• Tissue at base of petiole dies
• Senescence (aging)
• Autumn leaves withering flowers

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ETHYLENE
Ethylene is a gas that acts as a plant hormone.
It is neither truly lipid nor peptide based. The
formula is C2H4 making it a hydrocarbon which is
lipid soluble. It is produced from the breakdown
of methionine present in all plant cells and as
such all plant tissues produce it.
Ethylene can cross the cell membrane, but is
picked up by a receptor protein creating a signal
transduction pathway.
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Ethylene Signal Transduction
Activates transcription of numerous enzymes
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CTR1

• TWO-COMPONENT SIGNALING SYSTEM
• Receptors in the membrane.
• Receptors in the ER membrane

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ETHYLENE Frequently used commercially to allow
green fruit to be shipped and ripened at the
vendor or in route.
As fruit ripen, ethylene is released causing
production and release of ethylene in other fruit
close by. Domino Effect!
Silver and Cobalt ions are found in soil, water,
and fertilizers
As fruit respires in the ripening process, CO2 is
released and can compete for ethylene receptors.