Seasonal variations in hydrogen cyanide concentration of three Lotus species

Cyanogenic glucosides, generally considered antinutritional factors, are important defense molecules against predators and, in some cases, diseases. The objectives of this study were: (i) to determine the seasonal variations in hydrogen cyanide (HCN) concentration of three widely grown Lotus spp. and (ii) to assess the overall cyanogenic potential of the different plant components of a rhizomatous cultivar of broadleaf birdsfoot trefoil [Lotus corniculatus L.] (BFT). In this study, we used BFT cultivars Norcen and ARS-2620, narrowleaf trefoil (L. glaber Mill.) germplasm ARS-1207, and big trefoil (L. uliginosus Schkur.) germplasm ARS-1221. The experiments were conducted in the field and greenhouse using a randomized complete block design. Significant seasonal variations in HCN concentrations in Norcen, ARS 2620, and ARS-1207 were observed. Hydrogen cyanide concentrations were greatest in spring and summer and least in winter. ARS-1221 was acyanogenic, Of tire three cyanogenic entries grown in the field study, ARS-1207 had the greatest concentration of HCN, averaging 900 mug g(-1) dry matter while Norcen and ARS-2620 had similar levels of HCN. In the greenhouse, Norcen and ARS-1207 had greater HCN concentrations than ARS-2620. partitioning of the rhizomatous BFT cultivar ARS-2620 demonstrated that leaves and powers produced the greatest concentration of HCN, five times as much as stems and ripe-seed pods. Rhizomes, which are typically produced in winter and fall, did not exhibit HCN production. Seeds of Norcen and ARS-2620 were acyanogenic, but ARS-1207 seeds were weakly cyanogenic. However, as seeds germinated and seedlings formed cotyledons, Norcen, ARS-2620, and ARS-1207 exhibited HCN. Roots of all species were acyanogenic.