Ethylene
 
Ethylene, the ripening hormone is usually estimated in fruits during storage as well as for physiological studies. Ethylene level is also measured in infected plants.
 
 



Principle
The ethylene evolved is measured in a gas chromatograph based on the adsorption


Principle on activated silica gel or poropak.
 
 
Materials
⇒ Conical Flasks or Cylinders with facility to seal with Rubber Gaskets
⇒ Air-tight Syringes
⇒ Ethylene Gas
⇒ GLC - see, 'nitrogenase enzyme' for operating conditions.
 
 
Procedure

1.	Place the fruits in conical flasks or cylinders
2.	Seal the mouth with rubber septum or gasket
3.	Incubate for 1h at 20°C
4.	Withdraw gas samples with hypodermic syringes and inject into GLC.
5.	For standard, inject pure ethylene into empty conical flasks or cylinders of same volume and satisfy identical assay conditions. Remove the same volume of internal atmosphere as that of sample from the flask, inject into GLC and measure ethylene peak height.

 
 
Calculation
Refer nitrogenase.
The quantity of ethylene produced is expressed as ml ethylene per hour per kg material.
 
 



Notes
1. Depending upon the size and quantum of fruit sample, select suitable conical flasks or cylinders.
2. For studying rate of ripening select fruits without any macroscopic wounds and remove surface dirt.
 
 



References
1. Teitel, D C, Ahavoni, Y and Barkai-Golan, R (1989) J Hortic Sci 64 367.