“…There are several studies which analyze the amount of cyanide-liberating compounds in plants, its spatial distribution, and its dependence on environmental conditions (Jones, 1966;Cooper-Driver and Swain, 1976;Abbott, 1977;Cooper-Driver et al, 1977;Ellis et al, 1977a;Till, 1987;Caradus et al, 1990;Blaise et al, 1991;Hughes, 1991;Shore and Obrist, 1992;Calatayud et al, 1994;Caradus and Forde, 1996;Schappert and Shore, 1999a;Gleadow and Woodrow, 2000a). However, the central aspect of cyanogenesis, the capacity to release hydrogen cyanide from these endogenous compounds to the atmosphere, was just roughly classified by Byes^or Bno^or semiquantitative estimation by FeiglYAnger test paper methods (Hayden and Parker, 2002).…”