Kseniya Mikhailovna Nikerova

Inhibition of plant growth due to micronutrient deficiency is a consequence of several structural and functional changes and disorders. In this study, the effect of salicylic acid (SA) treatments on barley root growth and mitotic activity of the root apical meristem cells under micronutrient deficiency was studied. The results demonstrated that plants without SA treatment (Control) under micronutrient deficiency did not have significant changes in root size and biomass. Nevertheless, the proportion of cells with K-mitosis and vagrant chromosomes in metaphase, as well as bridges, forward and laggard chromosomes in anaphase increased at zinc or copper deficiency. The effects of SA on the growth and mitotic activity of barley root cells under zinc or copper deficiency differed depending on the treatment method. SA seed treatment (SA 1) increased root length and raw biomass, but decreased the proportion of cells with ring chromosomes and bridges in metaphase and anaphase, respectively. Leaf spraying with SA (SA 2) increased root length and decreased the proportion of cells with ring chromosomes and laggard chromosomes in metaphase and anaphase, respectively. At the same time, under micronutrient deficiency the proportion of cells with K-mitosis in metaphase, as well as forward chromosomes and chaotic chromosomes segregation in anaphase increased in SA 2. Besides, under copper deficiency the highest number of variants of complex disorder combinations was detected. The findings of this study indicate that SA seed treatment SA is more effective in reducing the negative effect of micronutrient deficiency on the apical meristem of barley roots.

Biomineralization in plant tissues is a widespread process accompanied by carbon fixation in biogenic minerals. This study aimed to evaluate the effect of CaCO₃ application to soil on the formation and localization of biominerals in the pericarp of fruits of Buglossoides arvensis (L.) I.M. Johnst., as well as on the accumulation of carbon in minerals. B. arvensis seeds were sown in the soil treated with CaCO₃ at concentrations of 0.0 (0 Ca), 2.5 (2.5 Ca), 5.0 (5 Ca), 7.5 (7.5 Ca), and 10.0 (10 Ca) t ha⁻¹. As a result of CaCO₃ application, on average across all treatments, the increase in soil pH was 30%, and the calcium and silicon content in the soil increased by 60 and 39%, respectively. The fruit weight was 4, 28, 42, and 21% higher in 2.5 Ca, 5 Ca, 7.5 Ca, and 10 Ca plants than in 0 Ca plants. Scanning electron microscopy analysis revealed the presence of silica and calcium carbonate in the pericarp of B. arvensis fruits, but showed no significant differences in the localization of biominerals in the pericarps between the treatments. The content of biosilica (phytoliths) was lower in 2.5 Ca, 5 Ca, 7.5 Ca, and 10 Ca plants than in 0 Ca plants, respectively, by 11, 14, 25, and 19%. The content of organic carbon occluded in a unit mass of phytoliths was, on average, 49% higher in treated than in 0 Ca plants. The content of carbonate fraction in fruits was 13, 14, 20, and 21% higher in 2.5 Ca, 5 Ca, 7.5 Ca, and 10 Ca plants than in 0 Ca plants, reflecting the effect of soil calcium levels on carbonate content in B. arvensis pericarp. Thus, in the pericarp of fruits, the ratio of silica to carbonates changed towards a decrease in silica content and an increase in carbonate content as the availability of calcium in the soil increased. In summary, B. arvensis responds to increased soil calcium and soil pH by increasing carbon accumulation in biominerals formed in fruit pericarps, supporting the potential for variability in plant biomineralization characteristics under changing growth conditions.

Biomineralization in plant tissues is a widespread process accompanied by carbon sequestration in biogenic minerals. This study aimed to evaluate the effect of CaCO₃ application to soil on the yield of Buglossoides arvensis (L.) I.M. Johnst., on the formation and localization of biominerals in the pericarp of fruits, as well as on the accumulation of carbon in minerals. B. arvensis seeds were sown in clay loam soil treated with CaCO₃ at concentrations of 0.0 (0Ca), 2.5 (2.5Ca), 5.0 (5Ca), 7.5 (7.5Ca), and 10.0 (10Ca) t ha⁻¹. CaCO₃ application improved B. arvensis germination, plant biomass accumulation, fruit weight and number, which consequently increased both per plant and per area yield, but did not significantly affect the rate of photosynthesis and leaf respiration. Scanning electron microscopy analysis showed no significant effect of soil liming on the localization of amorphous silica and calcium carbonate in the pericarp of B. arvensis fruits. However, with increasing soil calcium availability, the silica to carbonate ratio changed towards a decrease in silica content and an increase in carbonate content. Liming of soil from acidic to slightly alkaline increased the content of organic carbon, occluded in biosilica (phytoliths) and also increased carbon content of calcium carbonate in the pericarp of B. arvensis fruits. We concluded that B. arvensis responds to increased soil calcium and soil pH by increasing carbon sequestration in biominerals formed in fruit pericarps. Studying the relationship between biomineralization in plants and environmental conditions may be useful for assessing key biogeochemical processes of carbon sequestration.

The physiological role of biomineralization in plants is very diverse, with the main function being to help plants adapt to environmental factors. In addition to physiological significance, the formation of structural biominerals in plants is of great importance for paleoevironmental reconstructions, phylogenetic studies, assessment of the biogeochemical cycle of carbon and other elements, as well as for the use of biominerals in a wide range of technologies. This study investigated the presence and distribution of minerals in the pericarp of eremocarps of six species from different tribes of the Boraginaceae family. Scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy and X-ray diffraction analysis were used to identify biominerals. Amorphous silica and calcium carbonate in the form of calcite were identified as structural biominerals presented in the pericarps of species examined. While silica was deposited generally in the cell walls, calcite was found to precipitate in the intracellular and pore spaces. This structural localization of biominerals may indicate differences in their functions and genetic control of formation. Significant diversity in the intensity of biomineralization and distribution of biominerals can be largely related to plant ecology.

The actual study is the description of the biochemical characteristics of a wide range of enzymes (phenylalanine ammonia lyase, superoxide dismutase, catalase, peroxidase, polyphenol oxidase) and metabolites (malondialdehyde, phenols, extractives, cellulose, lignin), as well as the profiles of their activities during the xylem structural elements’ formation during the predominance of differentiation processes during straight-grained wood formation or proliferation while the figured wood formation in the radial row cambial zone (Fraction 1)—differentiating xylem (Fraction 2)—mature xylem (MX) in the period of active cambial growth in 16-year-old straight-grained Betula pendula var. pendula and figured Betula pendula var. carelica plants. We generalized the processes associated with abnormal xylogenesis were separated spatially, and, to the greatest extent, the metabolism of the studied birch forms differed in the Fraction 2, while the diagnostic contribution of secondary metabolism enzymes and malondialdehyde (MDA) probably characterized the active secondary metabolism of parenchyma cells, which formed figured wood basis. This study described for the first time the biochemical features of a wide range of enzymes and metabolites as well as the profiles of their activities in the xylem structural elements’ formation. The necessity of separately analyzing all tissue complexes was proven. This approach made possible to separate the generally observed biochemical patterns spatially. Thus, during the active cambial growth period in 16-year-old B. pendula var. pendula and B. pendula var. carelica, the differences between straight-grained plants and Karelian birch plants (non-figured and figured trunk parts) were most clearly expressed in the differentiating xylem.

Background: The mechanisms that control the accumulation of woody biomass are of great interest to the study. Invertase and sucrose synthase are enzymes that are vital for distributing carbon in various biosynthetic pathways. Karelian birch (Betula pendula var. carelica) is a form of silver birch (B. pendula Roth) and is characterized by disruption of the differentiation of cambium derivatives towards both the xylem and phloem, which leads to a change in the proportion of the conducting tissues' structural elements and the figured wood formation. We researched the expression profiles of genes encoding sucrose-cleaving enzymes (CWINV and SUS gene families) and genes encoding CVIF protein, which is responsible for the post-translational regulation of the cell wall invertase activity. Objective: In our study, 16-year-old common silver birch (Betula pendula var. pendula) and Karelian birch were used for sampling non-figured and figured trunk section tissues, respectively. Samples were selected for the research based on the radial vector: non-conductive, conductive phloem, cambial zone - differentiating xylem - mature xylem. Methods: The enzyme's activity was investigated by biochemical methods. RT-PCR method was used to determine the level of gene expression. Anatomical and morphological methods were used to determine the stage of differentiation of xylem cambial derivatives. Results: Our research revealed a shift in the composition of xylem components in figured Karelian birch, characterized by increased parenchymatization and reduced vessel quantity. In all studied trunk tissues of Karelian birch, compared with common silver birch, an increase in the expression of the CWINV gene family and the SUS3 gene and a decrease in the expression of SUS4 were shown. Conclusion: Therefore, the increase in parenchymatization in figured Karelian birch is linked to a shift in sucrose metabolism towards the apoplastic pathway, indicated by a higher cell wall invertase activity and gene expression. The expression of the SUS4 gene correlates with the decrease in xylem increments and vessel proportion. The research findings will enhance our understanding of how sucrose breaking enzymes regulate secondary growth in woody plants and aid in developing practical timber cultivation methods.