The article presents an analysis of the artificial dehydration effect of peach leaf tissues, simulating natural drought, on various physiological, morphological, and anatomical parameters described in the literature, associated with the trait of drought resistance. An investigation aimed to identify the most informative criteria for peach drought resistance which correlate with water loss during dehydration. The results present an assessment of the amount of water loss in 60 peach cultivars selected from different geographical areas and having different genetic origins. Four contrasting genotypes were identified, based on the results of the cluster analysis performed on the cultivar’s water regime. The influence of water regime parameters (leaf water content, water saturation deficit, dynamic of water loss), the morphological and anatomical structure of the leaf, the content of photosynthetic pigments, and the activity of the photosynthetic apparatus on drought resistance were investigated for selected peach cultivars. It was revealed that the most informative criteria for assessing drought resistance were dry and fresh leaf weight, leaf blade length, leaf width, and area (among morphometric parameters); stomatal pore length, stomata density, adaxial and abaxial epidermis thickness, and adaxial cuticle thickness (among anatomical parameters); and Fv/Fm—maximum photochemical quantum yield of PSII, Y(NO)—quantum yield of unregulated non-photochemical light energy dissipation in PS II and Y(NPQ)—controlled quantum losses (among indicators of photosynthetic activity).

Common hyssop (Hyssopus officinalis L.) is widely used as an aromatic and medicinal plant. In the component composition of the essential oil from the above-ground mass of H. officinalis f. cyaneus, from the collection of the Nikita Botanical Garden, the bicyclic monoterpene ketones isopinocamphone (50.99–64.41%) and pinocamphone (3.95–18.88%) predominate, which allows us to attribute this form to the isopinocamphone chemotype for use in pharmacology. An essential oil sample with a high content of isopinocamphone (70.74%) in complete absence of pinocamphone was determined, which made it possible to use the plant as a starting material for breeding. The objective of our work was to study the component composition of the essential oil of this form, and the morphology, anatomy and ploidy level of microshoots in vitro on a nutrient medium with BAP. This was compared with ex situ samples to develop a cultivation technique with the preservation of a valuable trait for use in task-oriented selection. Biotechnological methods are used for future mass propagation, study and the preservation of breeding forms. Morphological and anatomical features and ploidy of H. officinalis microshoots were studied in vitro. Using in vitro culturing of microshoots on MS medium containing BAP, a decrease in the cuticular layer and the degree of development of collenchyma near vascular bundles in leaves were shown compared to microshoots ex situ. Significant structural changes were found with a high increase in BAP concentration, while no changes in the ploidy level were detected.

Two models of Arabidopsis thaliana rhizogenesis in vitro were studied: (1) from the callus and (2) leaf explants petioles on the Murashige and Skoog one-tenth strength hormone-free nutrient medium and also with the addition of a growth regulator, such as indole-3-butyric acid. Morphological and anatomical studies show significant changes in the structure of the roots formed de novo in vitro from callus tissue, while the organs from leaf explant petioles were similar to those formed from seeds (primary). By the Sabinin–Kolosov method, a decrease in the percentage of the active root surface was established. The occurrence of structural changes during in vitro rhizogenesis and their effect on root functionality are discussed.

Understanding the transcriptional responses of plants under cold stress conditions is critical for olive cultivation, particularly in regions prone to extreme weather fluctuations and especially with increasing threats from climate change. In controlled experiments, we subjected leaves of three cold-tolerant and three cold-susceptible cultivars to moderate (−7 °C) and severe (−12 °C) freezing stress, followed by recovery at baseline temperatures. The study measured photosynthetic efficiency and enzymatic activity and showed physiological and gene expression changes using different methods. Distinct transcriptomic adaptations were revealed. Cultivars displayed enhanced differential expression associated with photosynthetic recovery and gene regulation in metabolic pathways. Two overlapping DEGs with increased expression were found in all cultivars during initial freezing.

Background. The base for a molecular analysis is DNA of high quality. For DNA isolation, different kits or classical methods are used. For mass analysis, isolation with kits is a very expensive process. So, the objective of our investigation was to find a cheap method for high-quality DNA isolation from leaves of various thyme cultivars.Materials and methods. Leaves cut from thyme accessions (Thymus mastichina L. cv. ‘Svetliachok’, T. striatus Vahl. cv. ‘Jubileiniy’, T. vulgaris L. cv. ‘Fantasia’, and T. vulgaris cv. ‘Jalos’.) maintained ex situ in the collection of the Nikita Botanical Gardens were used as the material for the analysis. Light microscopy was used to study leaf anatomy and localize essential oil on leaf cross sections. Essential oil was extracted on Ginsberg devices, and phenolic content was measured with The Folin–Ciocâlteu reagent (FCR). Commercial kits (DiamondDNATM, PureLink® Plant Total DNA Purification Kit) and classical methods (CTAB, CTAB with 2% polyvinylpyrrolidone) were used for DNA isolation. DNA quality was evaluated spectrophotometrically, with electrophoresis (horizontal, automated system Agilent 4200 TapeStation) and PCR.Results. The analysis showed that the leaf blade mesophyll of four thyme cultivars had inclusions with essential oil. The content of essential oil and phenolic compounds was measured biochemically. Since the plants were characterized by the presence of secondary metabolites, DNA was isolated by different methods. Spectrophotometry demonstrated that the classical CTAB method and CTAB with 2% PVP provided the best results. Using an automated electrophoresis system, the presence of high-molecularweight DNA (more than 52000 bp) in significant amounts was detected in the samples isolated with DiamondDNATM kit and CTAB + 2% PVP.Conclusion. Among the tested kits and methods, CTAB + 2% PVP provided thyme DNA suitable for PCR and, presumably, for genome library preparation. The low cost of reagents for this technique makes it applicable for future mass analysis of plant material.

Background.Olive (O. europaeaL.) is one of the main fruit crops in the world. It is most widespread in the Mediterranean region. In recent years, due to global warming and aridization of the earth, most olive-producing countries have suffered significant losses and are forced to transfer olive plantings from the traditional southern regions to the more humid northern ones. Insufficient precipitation and lack of irrigation water are currently some limiting factors in this crop's spread. Producers are increasingly focusing on planting drought-resistant cultivars that could produce high and regular yields in conditions of insufficient water supply. In this regard, this study aimedto identify genotypes of O. europaeawith high adaptive ability to the arid conditions of southern Russia and to determine the most informative indicators of drought resistance for collection screening. Materials and methods.Studies of water regime indicators (water-holding capacity, water deficiency, water content) and relative electrolyte yield, when the cell membrane is damaged under conditions of dehydration of leaf tissues, were carried out on 60 intraspecific hybrids of European olive. Corregiolo and Ascolano cultivars served as the control. The experiments were performed in laboratory conditions under controlled temperature of 30°C and relative air humidity of 30%. After leaf tissues' saturation with water (control), as well as after they were dehydrated for 24, 48 and 72 hours, drought resistance indicators were assessed. Results.Based on a cluster analysis, the main indicators of drought resistance, four groups of olive genotypes with different resistance to drought were identified. The greatest interest is for hybrids in the group with very high drought resistance. This cluster consists of 14 of the most promising hybrids that are superior in drought resistance to the control olive variety Ascolano. Water loss for these accession varied from 20.81 to 33.63%, and the relative yield of electrolyte varied from 0.27 to 0.36 RU, which allows us to conclude that their drought resistance is very high. Based on the analysis of principal components between various criteria of the water regime of olive plants, the relationship and influence on the integral assessment of drought resistance was shown. It is noted that the most informative indicator, which has a negative correlation with water loss and the relative yield of electrolytes when the cell membrane is damaged, is water-holding capacity. Indicators of drought resistance such as water content in leaves, water deficit, and relative water content in leaves are not sufficiently informative for the selection breeding of drought-resistant cultivars and forms of olive.