Changes in cyanogenic glucoside content in seeds and seedlings of Hevea species
1991
Selmar, D. | Germany. | Lieberei, R. | Junqueira, N. | Biehl, B.
The content of cyanogenic glucosides in seeds of several Hevea species was investigated. Whereas in all seeds tested large quantities of the cyanogenic monoglucoside, linamarin, were detectable, lotaustralin, which occurs in much lower concentrations, did not occur in every individual seed. After storage, the cyanogenic diglucosides, linustatin and neolinustatin, were also detectable in Hevea seeds, implying that the monoglucosides, linamarin and lotaustralin, are glucosylated to yield the respective diglucosides, linustatin and neolinustatin. The content of cyanogenic glucosides was also monitored during germination and seedling development of several Hevea species. Depending on the species investigated, and even on the varieties of one species, the patterns of developmental changes in HCN-potential were quite different. Whereas in 'wild type' H. brasiliensis seedlings the HCN-potential decreased to less than 15% of the initial content, it remains nearly constant in those of variety FX 25. However, during seedling development of H. benthamiana, H. camargoana and H. pauciflora, the HCN-potential first increased and later decreased. These changes depend on two contrary processes, conversion of cyanogenic glucosides to non-cyanogenic compounds and de novo synthesis of cyanogens. Variations result from quantitative differences in consumption and de novo synthesis of cyanogenic glucosides as well as from differences in the times when these two processes are initiated.
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