New Scientist Magazine recently published an article discussing the detrimental impacts of increased carbon dioxide emissions on the cassava plant. Cassava is known to be an important dietary component for over half a billion of the world’s impoverished population. It is especially popular in the drier regions of Africa, as it thrives quite well in periods of drought. However, this staple food may be becoming increasingly dangerous as CO2 levels in the atmosphere increase. Why? Because as CO2 levels increase, the amount of cyanide stored in the leaves of the Cassava plant also increases.

Cassava contains glycosides in both the leaves and the roots of the plant. When crushed, these parts of the plant release hydrogen cyanide, which is quite toxic to the human body.

The study, conducted by Ros Gleadow of Monash University in Melbourne, Australia, found that approximately 9 percent of the Nigerian population has some degree of cyanide poisoning due to the consumption of raw Cassava leaves. Additionally it was found that when the CO2 levels in the air are doubled, the amount of cyanide found in Cassava leaves also doubles. The discovery of this direct, one-to-one ratio of carbon dioxide to cyanide increase has triggered an urgent search for Cassava varieties that produce much less cyanide.

The people living in regions that rely on Cassava may have a difficult time surviving as the plant gradually becomes less safe to eat. It is becoming clear that unless an alternate staple crop is found, the cyanide levels in Cassava will begin to affect the citizens of its dependent populations quite severely.

Discussion question: Is it possible that other crop plants are becoming toxic because of high ozone levels? How might you determine if other crop plants make toxic compounds in response to increasing ozone levels? What family of plants would you examine first?

News Article Link:
http://www.newscientist.com/article/