Advances in Nursery Production of Hazelnut Plants in Serbia − Successful Grafting of Different Corylus avellana L. Cultivars and Clones Onto Corylus colurna L. Rootstock

The latest trends in hazelnut production are moving in the direction of selection and breeding of more productive cultivars, isolation of native clones, and more intensive clonal selection of rootstocks aimed at enhancing the agronomic performance of plants. Serbia stands out in the production of quality planting material by grafting on Turkish filbert (Corylus colurna L.), which does not form shoots and develops in the form of a tree. The aim of this research was to investigate the success achieved by grafting leading Italian cultivars (Tonda gentile romana, Tonda di Giffoni, and Tonda Gentile della Langhe) and their clones on Turkish filbert seedlings using technology developed at the University of Novi Sad, Faculty of Agriculture, Serbia, as well as determine possible differences in the quality and variability of the obtained planting material. For this purpose, from the end of March to the end of April, two-year-old C. colurna generative rootstocks (seedlings) were grafted by the whip and tongue method. At the beginning of September, the grafted plants were counted, and after the plants entered the dormant period (autumn in the year of grafting), they were taken out of the soil and classified. The obtained results revealed that the chosen hazel cultivars and clones exhibited excellent grafting success rate. In both analyzed years, as well as throughout the entire study period, greater grafting success was achieved using clones relative to the main cultivars. Over the two-year study period, the highest grafting success was achieved by clone AD17. Class I grafted plants were obtained in 80% of the cases, especially with Tombesi and AD17 clones, while significantly fewer Class I grafted plants were produced by grafting basic cultivars. Clones AD17 and Tombesi also produced grafted plants of greatest height and graft union diameter. All clones exhibited superior uniformity (i.e., a more stable grafting success) relative to their basic cultivars.

Cellular and Metabolite Changes in the Secondary Phloem of Chinese Fir (Cuninghamia lanceolata (Lamb.) Hook.) during Dormancy Release

Wood in the cold temperate zone is the product of the alternation of the growing season and the dormant period of trees, but our knowledge of the process of dormancy release in trees remains limited. Chinese fir (Cuninghamia lanceolata (Lamb.) Hook.) was used to investigate cellular and metabolite changes in the secondary phloem tissue during dormancy release. The sampling dates were 2 March, 28 March, and 13 April. The microsections of wood-forming tissue were prepared using the paraffin embedding technique to observe the formation of cambium cells; metabolites in secondary phloem cells were extracted using a methanol/chloroform organic solvent system. The results showed that the secondary phloem consists of phloem fibers, sieve cells and phloem parenchyma. The cells were regularly arranged in continuous tangential bands and were in the order of Phloem fiber-Sieve cell-Phloem parenchyma-Sieve cell-Phloem parenchyma-Sieve cell-Phloem parenchyma-Sieve cell-Sieve cell-Phloem parenchyma-. The Chinese fir cambium was in dormancy on 2 March and 28 March, while on 13 April, it was already in the active stage and two layers of xylem cells with several layers of phloem cells were newly formed. The width of the cambium zone increased from 18.7 ± 5.7 μm to 76.5 ± 3.0 μm and the average radial diameter of sieve cells expanded from 15.4 ± 7.5 μm to 21.5 ± 7.4 μm after dormancy release. The cambium zone width and the average radial diameter of sieve cells before and after dormancy release were significantly different (p < 0.01). The phloem parenchyma cells without resin were squeezed and deformed by the sieve cells, and the width of the phloem during the active period was 197.0 ± 8.5 μm, which was larger than that during the dormant period. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based metabolomics was employed to analyze the secondary phloem of Chinese fir on 28 March and 13 April. Thirty-nine differential metabolites during dormancy release were detected. The results showed that the composition of Chinese fir metabolites was different before and after dormancy release. The relative increase in pyruvic acid and ascorbic acid contents proved that the rate of energy metabolism in Chinese fir increased substantially after dormancy release. Changes in cell development and the composition of metabolites revealed that the dormancy release of Chinese fir was at early April and the formation period of phloem tissue is earlier than xylem tissue.

Biology and distribution of Orchis purpurea subsp. caucasica (Regel) B. Baumann et al. (Orchidaceae Juss.) in the Sochi Black Sea region

Orchis purpurea subsp. caucasica (Regel) B. Baumann, H. Baumann, R. Lorenz et Ruedi Peter is widespreadin the Sochi Black Sea region. It occurs on forest edges and in secondary woodlands of the lower mountain zone. Thenumber in individual populations is from 3 individuals to several dozen, occasionally there are clusters of up to 400individuals. The abundance varies greatly depending on the weather conditions and other factors. The species is winterlate-spring-green with a summer-winter dormant period. The growing season lasts 4–4.5 months. The criterion foridentifying ontogenetic states is the number and size of leaves, the number of leaf veins. Ontogenetic spectra of populationsare single-peaked with a predominance of adults; in more favorable growing conditions, two-peaked with a maximum ofjuveniles. Populations are full-member, normal type, stable. Seed renewal. Fruit formation is about 37.3 %. The numberof seeds in one capsule is from 6 to 28 thousand, one individual produces up to 80 thousand complete seeds per season.Orchis-type seeds, club-shaped, about 0.4 mm long; the embryo is large, round in projection. The species is protected inthe Caucasian State Natural Biosphere Reserve and the Sochi National Park.

TO THE BIOLOGY OF OENANTHE AQUATICA (L.) POIR. (UMBELLIFLORAE)

The results of experiments on seed germination and the initial stages of ontogenesis of the hygrohelophyte Oenanthe aquatica under laboratory conditions are presented. The features of fruit germination and the initial stages of ontogenesis of Oenanthe aquatica (L.) Poir were studied. It was revealed that mature fruits of O. aquatica do not have a dormant period. Germination of both freshly harvested fruits and those subjected to various storage conditions for 4 months (in laboratory conditions, refrigerator and freezer), showed a high percentage of laboratory germination from 90.6 to 100%. At the same time, storage of fruits in the freezer and in the refrigerator led to a decrease in the lag-time and germination period (in comparison with those of freshly picked fruits and fruits stored at room temperature). It was revealed that the fruits of O. aquatica germinate without a dormant period. It was shown that the development of O. aquatica seedling under laboratory conditions lasts about 30 days. The transition of a plant to a juvenile ontogenetic state occurs when the cotyledon leaves die off and is accompanied by the appearance of all the main plant organs. The sprout is a monopodially growing rosette shoot with main and adventitious roots. The juvenile plant is also represented by a uniaxial monopodial and anisotropic rosette shoot. The transition to an immature age-related state is characterized by the preservation of the rosette form of growth and the appearance of axillary buds on the shoot. In juvenile and immature age states, plants usually hibernate. It was revealed that already at the seedling stage, the polyvariance of ontogenesis is traced according to the rates of development of plants (growing in Petri dishes and floating on the surface of the water in beakers), associated with different rates of plant transition from the seedling phase to the juvenile age state.

The Cysteine-Rich Peptide Snakin-2 Negatively Regulates Tubers Sprouting through Modulating Lignin Biosynthesis and H2O2 Accumulation in Potato

Potato tuber dormancy is critical for the post-harvest quality. Snakin/Gibberellic Acid Stimulated in Arabidopsis (GASA) family genes are involved in the plants’ defense against pathogens and in growth and development, but the effect of Snakin-2 (SN2) on tuber dormancy and sprouting is largely unknown. In this study, a transgenic approach was applied to manipulate the expression level of SN2 in tubers, and it demonstrated that StSN2 significantly controlled tuber sprouting, and silencing StSN2 resulted in a release of dormancy and overexpressing tubers showed a longer dormant period than that of the control. Further analyses revealed that the decrease expression level accelerated skin cracking and water loss. Metabolite analyses revealed that StSN2 significantly down-regulated the accumulation of lignin precursors in the periderm, and the change of lignin content was documented, a finding which was consistent with the precursors’ level. Subsequently, proteomics found that cinnamyl alcohol dehydrogenase (CAD), caffeic acid O-methyltransferase (COMT) and peroxidase (Prx), the key proteins for lignin synthesis, were significantly up-regulated in silencing lines, and gene expression and enzyme activity analyses also supported this effect. Interestingly, we found that StSN2 physically interacts with three peroxidases catalyzing the oxidation and polymerization of lignin. In addition, SN2 altered the hydrogen peroxide (H2O2) content and the activities of superoxide dismutase (SOD) and catalase (CAT). These results suggest that StSN2 negatively regulates lignin biosynthesis and H2O2 accumulation, and ultimately inhibits the sprouting of potato tubers.

Prospects for the gene pool use of stone fruit plants in the distant hybridization of cherries

18 species of cherries are collected for the preservation and study in the gene pool of the station. The following species P. sachalinensis, P. kurilensis, P. pensylvanica, P. incisa, P. serrullata, P. lannesiana, P. fruticosa separated by economically valuable traits, were involved in distant hybridization as a female parent. Cherry varieties, donors of large – fruited fruit, performed as a male parent. The article shows the yielding results of interspecies crossing, the patterns of inheritance of hybrid traits of early and late emergence from the condition of a deep dormant period and winter hardiness. According to the results of our research, we recommended the following species – P. lannesiana, P. serrullata, P. sachalinensis as donors of short onset, and as for late and long-lasting – P. pensylvanica, P. incisa, P. fruticosa. Species which transmit the sign of winter hardiness to their progeny – P. fruticosa, P. incisa and P. kurilensis.

The dormant period of the apple tree and its change under the influence of destabilization of weather conditions

The article presents an analysis of the features of weather conditions in 2020 in the Central Black Earth Region. It determines main deviations from the average long-term values of air temperature and humidity, as well as the distribution of precipitation. It shows the influence of climate change in recent decades, the main of which is the destabilization of the water-temperature regime, on the passage of phenophases in the development of fruit plants, including the dormant period. The article studies various methods of determining the dynamic reaction of the photo-system of apple-tree plants of the varieties Lobo, Zhigulevskoe, Melba, Antonovka, Hani Crisp, Ligol on the stock 62-396 deep rest by non-invasive methods based on the analysis of photosynthetic activity and the intensity of photosynthesis of chlorophyll-containing tissues. It shows the prospects of non-invasive registration of photosynthetic activity of tissues of annual branches for monitoring the period of deep dormancy. It was found that the registration of real parameters of changes in the index of photosynthetic activity during the transition to deep dormancy is possible only in the field. Cut branches of plants, placed in favorable laboratory conditions, show smoothed parameters of fluctuations in the level of fluorescence of chlorophyll-a in assimilation tissues, depending on changes in the functional state of the plant organism.

Determination of the dates of the sweet cherry (Cerasus avium Moench.) trees dormant period completion and beginning of flowering

The author presents the results of evaluating the phenoclimatographic models application for determining the dates of the sweet cherry trees dormant period completion and beginning of flowering in the soil and climatic conditions of the South Steppe of Ukraine as well as the effect of the external factors (maximum and minimum air temperature), as the models parameters for the generative buds growth and development. The limit values of the phenoclimatographic indicators were established: CU (chill unit) required for the cultivar Krupnoplidna dormant period completion and GDH (growing degree hour) specified for the beginning of flowering. In order to emerge from the mentioned period completion cherries need to accumulate – 1350 оС CU, and for the beginning of flowering – 4839 оС GDH. The dates of the biological dormancy completion and flowering were based on these limit values of CU and GDH. The validation of the models by comparing the calculated and actual dates of the flowering beginning in the orchard showed that their divergence was in the range from 0 to 3 days. That is indicative of the high prediction accuracy of these dates. The intensity of the generative buds development appered depend on their physiological state, which was influenced significantly by the environment temperature conditions, first of all, maximum and minimum air temperature. After the accumulation of 43 % of the GDH limit index the period of the accelerated growth processes rate in the buds began which lasted just until the beginning of of the sweet cherry trees flowering. This occursed mainly in the period with positive air temperatures. The studies showed the possibility of using the phenoclimatographic indicators limit values: CU – for the selection of varieties with the late time of the dormant period completion, and GDH a criterion of the plant resistance to the negative effect of the spring frosts.

Dynamics of the isoenzyme composition of peroxidase and pigments in the needles of the introduced species of Picea (L.) Karst. in the taiga zone (Karelia)

The study was conducted at the Botanical Garden of Petrozavodsk State University (middle taiga sub-zone). The subjects of the study were an indigenous species (P. abies (L.) Karst.), and five introduced species (P. pungens Engelm. f. glauca Regel., P. pungens Engelm. f. viridis Regel., P. glauca (Mill.) Britt., P. omorica (Pane) Purk., P. mariana Britt., P. obovata Ledeb.). The study established high variability of the isoperoxidase spectrum in the Picea species needles during the circannual cycle. Molecular forms of peroxidase typical for growth and dormant periods were determined. Some Picea species were found to have isoenzymes appearing only during the deep dormant period. An increase in the heterogeneity of the needles isoperoxidase spectrum and appearance of molecular forms of the enzyme typical for the dormant period were observed in the indigenous and introduced Picea species in the course of adaptation to unfavorable winter conditions. The isoenzyme system rearrangement ensures plants tolerance to external factors and homeostasis regulation. The content of chlorophyll and carotenoids in the needles of the studied species undergoes significant seasonal changes and is largely determined by their biological characteristics. Pigments concentration naturally increases by the end of the vegetative period and decreases slightly in winter. The total number of pigments in the needles of the indigenous and introduced species is almost the same, indicating a similar rate of stock formation. By the dormant period, the ratio of chlorophylls to carotenoids increases and reaches approximately the same level in all Picea species. The Picea species introduced in Karelia adapt to low winter temperatures with the same physiological changes as the indigenous ones. These include changes in the isoenzyme composition of peroxidase, the dynamics of the pigments content in the needles, and the ratio of chlorophylls to carotenoids. Potential tolerance of the studied plant species to unfavorable environmental factors is affected by the extreme factor of tension that does not exceed the threshold value.