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The review analyzes and summarizes information on the history of development and the current state of methodological approaches to the qualitative and quantitative determination of phytohormones in plant tissues. Plant hormones play an indispensable role in many physiological processes during a plant life cycle, from seed’s germination to senescence. The determination of the endogenous hormones concentration is essential for elucidating the role of a particular hormone in any physiological process. A sensitive and quick analytical method of a simultaneous quantitative estimation of the main classes of phytohormones is essential for the investigation of signaling control networks in specific developmental pathways and physiological responses. In plant tissues, phytohormones are present in very low concentrations (from 10-9 M to 10-6 M); hence, the availability of highly effective, comprehensive and reliable analytical techniques for their identification is extremely important. The article gives a brief description of the main classes of plant hormones and outlines their functional activity. The importance of methods for hormones identification in plant tissues and their use in plant physiology and agricultural practice is discussed. The study presents a valid and tested sequence of procedures for the extraction of plant hormones, a methodology for purification of the obtained extracts from interfering substances and an up-to-date method of plant hormones quantification (indole-3-acetic, abscisic, gibberellic, salicylic acids and five forms of cytokinins). The quantification method combines a high-performance liquid chromatography with a mass spectrometry. Four chromatographic methods for the sepa­ration and detection of substances in aliquots as well as ionization conditions for hormones in a mass spectrometer are described. The presented analytical technique is adapted for scientific laboratories in Ukraine.

Plants of heterosporous annual fern hydrophyte Salvinia natans L. were collected in ponds of the Desniansky district of Kyiv city during summer time beginning from June, 2015 at one-month interval. Biometric studies of the whole plant (clone) and some segments of floating and submerged fronds showed that changes in the sporophyte weight and length at the various phenological phases of development occurred mostly owing to newly formed organs (modules) while linear dimensions of some formed fronds remained practically unchanged. The weight and length of an individual submerged frond considerably exceeded those of floating one. At the steady-state growth phase (July) the weight of an individual submerged frond increased two times due to an intensive formation of multi-cellular filamentous hairs while the length remained almost unchanged. During the reproductive development (August-September) the sporophyte weight increased as a result of sporocarps formation. The pattern of IAA accumulation and localization in organs of the sporophyte S. natans was for the first time analyzed using HPLC. At the phase of a fern intensive growth (June), the total IAA content of floating and submerged fronds was shown to be similarly high and reached 182 ng/g of fresh weight. During an active overgrowth and pubescence of submerged fronds (July) the endogenous IAA content was 546.3 ng/g of fresh weight while the quantity of this hormone in floating fronds remained at the level of the previous phase. A considerable reduction of this hormone content in ageing floating and submerged fronds was observed following the sporogenesis beginning at the phase of sporocarp formation and spore ripening. At the stage of late sporogenesis in the beginning of vegetative organs dying phase (September), the total IAA content in sporocarps that contained mature spores was 193 ng/g of fresh weight. The free hormone form dominated at the stage of an active and steady-state growth of floating and submerged fronds. Conjugated IAA was localized mostly in submerged fronds in quantity which exceeded that of floating ones 4 and 36 times, respectively. Distribution of this hormone between floating and submerged fronds shows that during the steady-state growth phase IAA is localized in submerged fronds, while at the phase of vegetative organs dying – in sporocarps. Specific changes in accumulation and localization of endogenous IAA revealed the correlation between growth processes and distribution, and content of phytohormone free and conjugated forms in sporophyte vegetative and reproductive organs of S. natans water fern during its individual development.

Phytohormonal balance changes in plants with contrast salt resistance – glycophyte Phaseolus vulgaris L. and halophyte Mesembryanthemum crystallinum L. – under salt stress (NaCl) were studied. It was assumed that salt tolerance of M. crystallinum is dependent on hormonal balance peculiarities, namely on, extremely low ABA level combined with high amount of IAA and cytokinins.