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In a study of seedlings of 72 entries representing 39 species, 14 genera, and 2 tribes of grasses, only entries of the genus Sorghastrum were found to contain the cyanogenic glucoside, dhurrin [(S)-p-hydroxymandelonitrile β-D-glucopyranoside]. Dhurrin was found in seedlings of each of the 10 entries of indiangrass [Sorghastrum mutans (L) Nash] and the three entries of S. pellitum.
Seedlings of five indiangrass cultivars were assayed for dhurrin concentration. Levels expressed as HCN potential (HCN-p) ranged from about 900 ppm for 'Holt' to about 1,200 ppm for 'Llano' and 'Oto'.
Further studies with Oto seedlings indicated that first leaves were higher and more uniform in HCN-p than were other portions of the shoot, but all shoot portions contained dhurrin. Seedling roots also contained illlurrin, but the HCN-p of roots was appreciably lower than that of shoots.
Spectral evidence indicated that dhurrin was present in extracts of leaves of tillers harvested from field-grown plants. Dhurrin was not detected in all such tillers, however, Indiangrass tiller extracts contained more interfering substances than seedling extracts, in agreement with previous observations on Sorghum seedlings.