Abstract
The activities of alkaline lipase (EC 3.1.1.3, AlkL), isocitrate lyase (EC 4.1.3.1. ICL), pyruvate kinase (EC 2.7.1.40. PK) and glucose–6–phosphate dehydrogenase (EC 1.1.1.49, G6PDH) were determined in cultured, dormant embryos of apple (Malus domestica Borb. cv. Antonówka), pretreated with gaseous HCN. The C6/C1, ratio was estimated in the same material. The activities of AlkL and ICL were not stimulated by HCN pretreatment until the period of maximum stimulation of germination. The activity of G6PDH was inhibited by cyanide only late during the culture of embryos. Therefore, the changes in these activities are considered to be the result and not the cause of enhanced germination. On the other hand, also PK, active very early during the culture of embryos, was modified as a result of the treatment. The cyanide‐induced changes in activity of this enzyme in cotyledons (inhibition followed by stimulation) were similar to those in the whole embryo, whereas its changes in the embryonal axis (stimulation followed by inhibition) resembled CN‐induced changes in PK in axes of apple seeds submitted to cold stratification (Bogatek and Lewak 1988). The estimation of C6/C1 ratios partly confirmed these observations. A role of HCN‐induced modifications of PK activity in embryonal dormancy is proposed.
Published Version
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