The content of endogenous phytohormones indolyl-3-acetic (IAA), gibberellic (GA3), abscisic (ABA), salicylic (SA) acids, cytokinins – t-zeatin (t-Z), t-zeatin-O-glucoside (t-ZG), t-zeatin riboside (t-ZR), isopentenyl adenin (iP) and isopentenyl adenosine (iPA) was determined using the high-performance liquid chromatography-mass spectrometry system Agilent 1200 in Dryopteris filix-mas gametophytes at different stages of its morphogenesis in culture in vitro. It was shown that GA3 and t-Z dominated in the thallus of 60-day gametophytes at the stage of spatulate prothallium development, which was marked by an intensive growth of the prothallium plate due to the division and extension of apical cells. The content of GA3 reached 229.9 ± 11.5 ng/g of fresh weight (f. w.) and t-Z was 56.1 ± 2.8 ng/g f. w. IAA dominated in the thallus of 90-day gametophytes, which were characterized by an active development of the archegonium cushion consisting of several layers of cells necessary for the further nutrition of the sporophyte, and formation of the archegonium and antheridium. At the final stage of morphogenesis, in the thallus of 120-day gametophytes, on the surface of which sporophytes have not yet appeared, active t-Z dominated, whereas in the thallus with sporophytes, the content of IAA reached the maximum value (395.5 ± 19.8 ng/g f. w.) that may indicate a direct involvement of the hormone in the regulation of the sporophyte growth and development. At this stage of morphogenesis, the accumulation of t-ZR and the emergence of ABA were observed. The maximum content of SA (287.7 ± 14.4 ng/g f. w.) occurred at the first stage of development. Subsequently, there was a significant reduction in the hormone level. In the thallus of gametophytes, on the surface of which the sporophyte was formed, the level of SA increased. The peculiarities of quantitative and qualitative changes have shown that physiological effects of the analyzed phytohormones is directed towards regulation the morphogenesis of Dryopteris filix-mas gametophyte.
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