Meeting Abstract
A major contributor to global biodiversity is the tremendously variable landscape of secondary metabolites characterizing organisms. Crushing or chewing leaves catalyzes a reaction that releases potentially toxic hydrogen cyanide gas (HCN) in over 3000 species of vascular plants representing 110 families of ferns, gymnosperms, monocotyledonous and dicotyledonous angiosperms. These include a diverse group of economically important crops such as cassava, stone fruits, lima beans, bamboo and cashews. Nearly all species of passion vines in the genus Passiflora (Passifloraceae) contain HCN-releasing cyanogenic glycosides. These compounds are key drivers of adaptive radiation in Passiflora and the highly specialized herbivorous insect taxa that consume them. The conventional method for quantifying cyanide concentration in Passiflora, and other biological samples, is the Lambert colorimetric procedure. This procedure can be prohibitive. It requires expensive analytical equipment, substantial investment of time in collecting and processing samples, and is restricted to laboratories that are often away from the field where study organisms occur. Here we present a new method for quantifying HCN concentration of biological samples that is cheap, flexible, efficient, and high throughput. This method is based on a simple apparatus assembled around a portable HCN meter developed for emergency personnel. An evaluation of the accuracy and validity of this method by comparison with the conventional Lambert procedure will be presented. We will conclude by taking this opportunity to showcase the utility of this method by presenting dynamic spatial and temporal patterns of HCN heterogeneity in tropical Passiflora that have been discovered using this technique.
