Undesirable effects of ethylene

1.Accelarated Senescence: In green tissue, ethylene application results in loss of chlorophyll, loss of protein, and susceptibility to desiccation and decay. The ethylene pollution can result in yellowing of leafy vegetables (spinach), fresh herbs and the green vegetable like broccoli as well as senescence of some flowers.

2.Accelerated ripening: Inspite of its beneficial effect on ripening, it can also be undesirable like premature yellowing of cucumbers. In storage, it reduces storage life.

3.Induction of leaf disorders: In many plants, exposure to ethylene results in darkening or death of portion of their leaves, commonly in foliage plants like lettuce. Ethylene causes a disorder in lettuce called as lettuce spotting in which the browning results from collapse and death of areas of cells following increased synthesis of phenolic compounds in response to ethylene.

4.Isocoumarin formation: In carrot ethylene exposure causes biosynthesis of bitter isocoumarins, which makes the carrot bitter.

5.Sprouting: In commodities intended for consumption, the ethylene stimulated sprouting is undesirable, e.g. sprouting of potatatos increases water loss leading to early shriveling.

6.Abscission of leaves flower and fruits.

7.Toughening of asparagus: Ethylene stimulates the lignification of xylem and fiber elements in the growing asparagus spear leading to undesirable toughness and reducing the portion of spear that is edible.

8.Induction of physiological disorder: Ethylene sometimes induces or hastens the appearance of physiological disorders of stored commodities. Rapid ripening of apples with low Ca contents induced high levels of the bitter pit storage disorder. In case of tulip bulbs, ethylene pollution results in failure of flowers to develop condition called ‘blasting.’

How to overcome the undesirable ethylene effects:

 1.Eliminating the sources of ethylene

2.Ventilation

3.Chemical removal:

• Potassium permanganate (KmnO4): It oxidizes ethylene to CO2 and H2O.
• Ultraviolet lamps: It produces ozone, which was thought to be the active ethylene-removing agents.
• Activated or brominated charcoal: Charcoal air purifier, esp if brominated, can absorb ethylene from air.
• Catalytic oxidizers
• Bacterial systems
• Hypobaric storage