Effect of Cyanogenic Glycosides on Growth of Callus from Almond and Plum

Abstract

Abstract The effects of the cyanogenic glycosides, amygdalin and prunasin, and their breakdown products, cyanide and benzaldehyde, on callus derived from ‘Marianna 2624’ plum (Prunus cerasifera Ehrh. × P. munsoniana Wight & Hedr.) and on that from 2 almond cultivars (P. amygdalus Batsch ‘Nonpareil’ and ‘Texas’) were compared. Prunasin (D-Mandelonitrile-β-D-glucoside) inhibited the growth of ‘Marianna 2624’ plum and ‘Nonpareil’ almond callus but not ‘Texas’ almond. Amygdalin (D-Mandelonitrile-β-D-gentiobioside) inhibited ‘Marianna 2624’ plum callus growth but promoted growth of both almond cultivars. All 3 cultivars were inhibited to the same extent by sodium cyanide, indicating that cyanide was not the differentiating inhibitory breakdown product of the cyanogenic glycosides. Benzaldehyde, another catabolite of prunasin and amygdalin, was strongly inhibitory to ‘Marianna 2624’ plum callus growth at 0.05 mm, but a concentration of 5 mm was required to inhibit similarly growth of either almond callus. The greater sensitivity of ‘Marianna 2624’ plum callus, compared to almond callus, to the cyanogenic glycosides and benzaldehyde, but not cyanide, suggests that benzaldehyde is an important factor in the almond/plum incompatibility.