Endogenous Phytohormones in Spontaneously Regenerated Centaurium erythraea Rafn. Plants Grown In Vitro

Phytohormones are important regulators of numerous developmental and physiological processes in plants. Spontaneous morphogenesis of the common centaury (Centaurium erythraea Rafn.) is possible on nutrition medium without addition of any plant growth regulator depending solely on endogenous phytohormone levels. Thus, this plant species represents a very good model system for the investigation of numerous physiological processes under phytohormonal control in vitro. We analysed the total amount of endogenous cytokinins (CKs) including the contents of their individual groups in shoots and roots of C. erythraea plants grown in vitro. The total amount of endogenous CKs was 1.4 times higher in shoots than in roots. Inactive or weakly active N-glucosides found to predominate in both organs of centaury plants, whereas free bases and O-glucosides represented only a small portion of the total CK pool. Consequently, centaury roots showed higher IAA content as well as IAA/free CK base ratios compared to shoots. Centaury tissues also showed increased levels of stress hormones. In contrast to SA, considerably higher levels of ABA were found in centaury shoots than in roots. Our results could serve as a basis for understanding and elucidating spontaneous de novo shoot organogenesis and further plant regeneration of C. erythraea in vitro.