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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #113857
Title: SEASONAL VARIATIONS IN HCN CONCENTRATION OF THREE LOTUS SPECIES

Author
item GEBREHIWOT, LUSEGED - UNIV OF MISSOURI-COLUMBIA
item Beuselinck, Paul

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2001
Publication Date: 5/1/2001
Citation: GEBREHIWOT, L., BEUSELINCK, P.R. SEASONAL VARIATIONS IN HCN CONCENTRATION OF THREE LOTUS SPECIES. AGRONOMY JOURNAL. 2001. V. 93(3). P. 603-608.

Interpretive Summary: Birdsfoot trefoil is a common name applied to three related Lotus species grown for forage in the United States, Canada, South America, and Europe. Birdsfoot trefoil can produce compounds that contain cyanide. Cyanogenic glucosides are generally considered as anti-nutritional factors because they can become toxic at high levels. However, cyanogenic glucosides are important in defending the plant from herbaceous predators, like insects, and diseases. In this study, hydrogen cyanide (HCN) was examined: i) to determine the seasonal variations HCN concentration of three widely grown Lotus species and ii) assess the overall cyanogenic potential of the different plant components of a rhizomatous cultivar of broadleaf birdsfoot trefoil. The experiments were conducted in the field and greenhouse and demonstrated that HCN concentrations were greatest in spring and summer and least in winter. Leaves and flowers produce the most HCN. Rhizomes, which are typically produced in fall and winter, did not exhibit HCN production. Roots of all species did not contain HCN. This information is important to researchers attempting to understand the genetic relationship among these trefoil species and to other plant scientists studying the ecology of these birdsfoot trefoil species in interactions with animals, insects, and diseases.

Technical Abstract: Cyanogenic glucosides, generally considered as anti-nutritional 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 species and ii) assess the overall cyanogenic potential of the different plant components of a rhizomatous cultivar of broadleaf birdsfoo trefoil (BFT) (Lotus corniculatus L). In this study, we used BFT cvs. 'Norcen' and ARS-2620, narrowleaf trefoil (L. glaber Mill.) ARS-1207, and big trefoil (L. uliginosus Schkur.) 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 HCN negative. Of the three cyanogenic entries, in the field study, ARS-1207 ha the greatest concentration of HCN averaging 900 ug/g of 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 flowers produce the greatest concentration of HCN, five times as much as stems and ripe-seed pods. Rhizomes, which are typically produced in fall and winter, did not exhibit HCN production. Seeds of Norcen and ARS-2620 were acyanogenic, but ARS-1207 seeds were weakly cyanogenic. However, as seeds germinate and seedlings form cotyledons, Norcen, ARS-2620 and ARS-1207 exhibited HCN. Roots of all species were acyanogenic. Thus, seeds and root samples are not reliable for characterizing cyanogenesis.