Re: How does etyhlene aid in the ripening process a banana?

Hi Kelly...Little attention was paid to the possible roles of ethylene as a natural growth regulator until the developement of gas chromotographic techniques in the 1960's. A gas chromotograph allowed them to measure every small amounts of ethylene as low as 1 ppm ( that one little part of the gas hanging around with 1 million parts of air). This help scientists to study this gas more precisely and they were able to established that ethylene is a plant hormone (do you understand what a hormone is?). Ethylene (CH2=CH2) being a gas moves (diffuses) through a plant much like Carbon Dioxide (CO2) does and can exert its effect in very small amounts. Its soluble (able to dissolve) in water so that helps it move in the plant. The coatings (cuticular) on the external cell surface normally prevents losses of ethlene from the plant. Ethylene is produced in meristems, fruits, flowers, seed and plants tissues during certain times (germinating seeds, ripening of fruits, more you can research).

Synthetic ethylene, from ethephon when applied to plant tissues and stimulate a great burst of natural ethylene production (the call this an autocatalytic effect). Just how ethylene exerts its regulatory effects is unfortunately no better known than the basic mechanisms of the other plant hormones. One theory is that ethylene regulates some aspect of DNA transcription or RNA translation, thus changing RNA-directed protein synthesis and, consequently, enzyme patterns. But there are many more mechanisms that likely are also in operation. Ethylene gas , injected into airtight storage rooms, is used comercially to ripen bananas. The application of ethephon at 1000 ppm will ripen bananas in about the same time period as 100 ppm of ethylene gas.

I'm sorry that your question can't be answered more precisely but maybe as a budding scientist you might help find the exact answer for us someday. I hope you can use the above imformation. You might try logging on to The National Agricultural Library or checking out Plant Science by Hartmann,. Kofranek, Rubatzky, and Flocker. Have fun and good luck on your project. Mark