CBN-V Video Archives - S6-28
Quantification of the Rate of Hydrocyanic Acid (HCN) Emission from the Leaves of Cassava (Manihot esculenta Crantz)

Ukpabi U.J. and A.O. Folorunsho

National Root Crops Research Institute, Umudike, PMB 7006, Umuahia, Abia State, Nigeria nrcri@infoweb.abs.net

        Alkaline picrate solution was used to monitor the emission of hydrocyanic acid from the leaves of three improved elite cassava genotypes, NR 41044, TMS 30555 and TMS 30211, being grown in the southeastern part of Nigeria. Results showed that the leaves emitted less HCN to the atmosphere than when immersed in aqueous solutions. It was found that in a dry hot afternoons, 28–32 oC, the leaves of a 4-months old plant of NR/41044 could give out as much as 0.85mg HCN/h to the atmosphere. The release of hydrogen cyanide to the environment by the leaves was found to be much lower in older plants. Furthermore, harvested leaves, stored under room temperatures of between 22 and 30 oC gave out 116–478 mg HCN/tonne/h. This underscores the need to genetically modify already accepted genotypes to reduce HCN emission to the environment.

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