ABSCISIC-ACID, POLYAMINES AND PHENOLIC-ACIDS IN SESSILE OAK SOMATIC EMBRYOS IN RELATION TO THEIR CONVERSION POTENTIAL

Two types of sessile oak (Quercus petraea (Matt) Liebl.) somatic embry os with well-developed ivory or green coloured cotyledons and root api ces differing in their development, i.e. in the conversion into plantl ets, were examined for the endogenous contents of abscisic acid (ABA), polyamines (PAs), aromatic monoamines (AMs), phenolic acids (PhAs), l ignin and peroxidase activity. The conversion did not occur in embryos with deep green cotyledons (NCE, nonconverting embryos) while almost 56 % of embryos with ivory or light green cotyledons converted into pl antlets (CE, converting embryos). High conversion capacity is associat ed with (a) lower content of ABA, (b) lower levels of free putrescine and its soluble conjugates, and higher content of spermidine soluble c onjugates, (c) markedly increased level of phenylethylamine and its so luble conjugates, and (d) significantly lower content of total PhAs re presented by the sum of free, soluble ester-and glycoside-, and insolu ble cell wall-bound PhAs as compared to the contents in NCE. Higher le vels of all determined free PhAs, and ten and three times higher conte nts of sinapic acid esters and glycosides, were found in NCE. On the c ontrary, three times higher ferulic acid content was found in the cell walls of CE. Higher content of lignin in NCE positively correlated wi th the amount of soluble phenolics and ionically bound peroxidase acti vity (EC 1.11.1.7). The results indicate that the alterations in pheny lpropanoid metabolism in sessile oak somatic embryos are closely relat ed to their developmental capability. (C) Elsevier, Paris.