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Actinidia kolomikta (Maxim) Maxim. is a winter-hardy species of the genus Actinidia Lindl., whose fruits are valued for their high content of vitamin C and other bioactive compounds. The use of biotechnological propagation methods significantly accelerates the production of quality planting materials for this crop. This study revealed the regeneration features of promising A. kolomikta cultivars. The main morphometric parameters of explants were determined in regard to the effect of different iron chelates (FeEDTA and FeEDDHA) and cytokinins (6-benzylaminopurine, meta-Topolin, and 2-izopentyladenine) in the Quoirin and Lepoivre medium. FeEDTA-supplemented media were optimal for explant culture. Meta-Topolin was found to promote the formation of adventitious microshoots at the base of explants and bud activation, which increased the multiplication rate by 1.5 and 1.7 times compared to the media with 6-benzylaminopurine and 2-izopentyladenine. The morpho-anatomical studies revealed the structural organization of assimilation tissues and the stomatal apparatus of A. kolomikta under different culture conditions (field, in vitro, and ex vitro). The stomata in vitro were round and had a larger area, lower thickness, and a lower layer number of mesophyll compared to field conditions. The transfer from in vitro to ex vitro caused gradual normalization of the leaf structure: a decrease in the stomatal number and area, changes in shape (from round to elliptical), and an increase in the mesophyll thickness.

ABSTRACT Actinidia Lindl., commonly known as kiwifruit, is a valuable berry crop. The area of commercial kiwifruit plantations is increasing; the global production of kiwifruit is about 0.62% of the total production of major fruit crops. The use of biotechnological methods, which can significantly accelerate the propagation of quality planting materials, is considered to be relevant for the propagation of this crop. In this study, we optimized the culture medium composition at the micropropagation stage for the effective cultivation of promising cultivars of A. arguta, A. kolomikta, and A. polygama. We investigated the features of Actinidia morphogenesis depending on the genotype, the concentration of 6-Benzylaminopurine (0.5, 0.8, and 1.0 mg L-1), and plant growth regulators (6-Benzylaminopurine, meta-topolin, and 2-isopentenyladenine at a concentration of 0.5 mg L-1) in the media Quoirin and Lepoivre. Actinidia arguta (multiplication rate of 8.0) and A. polygama (6.8) developed faster at the micropropagation stage compared to A. kolomikta (4.9). The studied Actinidia representatives were cultured most effectively on Quoirin and Lepoivre media supplemented with 0.5 mg L-1 meta-topolin, compared to the media containing 0.5 mg L-1 6-Benzylaminopurine and 0.5 mg L-1 2-isopentenyladenine. The use of meta-topolin in the medium contributed to the increase in various morphometric traits, such as the height of microshoots (up to 28% depending on the species), their number (up to 52%), and their multiplication rate (up to 42%). We also recorded a high morphogenic capacity of the investigated species.

Trichopilia suavis is one of the important representatives of the genus Trichopilia, which can be used as a potted plant for the interior design. also, its beautiful inflorescences are added unusual element to bouquet compositions and actively used in the production of perfumes. This study was carried out in order to develop and improve micropropagation method for mass clonal production of T. suavis through protocorm culture. Half-strength Murashige and Skoog culture medium (½) has been modified by adding different organic components and growth regulators. The protocorms obtained from seeds germinated by asymbiotic method were used as explants. The results showed that the optimal treatment for formation of new protocorms (7.50 ± 0.7 units per protocorm) was obtained by culture on ½ MS medium with 0.5 mg L-1 of 6-Benzylaminopurine (6-BAP) and 100 mL L-1 of coconut water. At the stage of rooting, the highest number and length of roots (7.0 ± 0.45 units per plantlet, 2.64 ± 0.18 cm) were obtained through subsequent cultivation of plantlets on ½ MS medium with 0.5 mg L-1 indolyl-3-butyric acid (IBA), 1.0 g L-1 charcoal with the addition of 50 g L-1 of banana puree. The obtained seedlings were successfully adapted in a substrate consisting of bark, perlite and peat in a ratio of 1:1:1.

Ornamental plants are cultivated for decorative and utility purposes in urban landscapes throughout the world. They are much valued for their aesthetic properties and constitute an important part of the global horticulture industry. Plant viruses and viroids of various taxonomic groups have a significant negative impact on ornamentals provoking a wide range of symptoms, reducing both decorative value and quality of propagated material and causing large economic damage. A significant growth of the ornamental plants market in recent years promotes the spread of viral diseases. Therefore, systematization of data on virus and viroid phytopathogens diversity in these cultures is an urgent research task. Among the most popular ornamentals are chrysanthemum, rose, clematis, canna, and lavender. More than fifty viruses and viroids from 17 different families (including two viroid families) have been identified in these crops to date. In the presented review, we described the variety of these pathogens and their effect on the above-mentioned ornamentals

ABSTRACT Apricot is one of the most valuable commercial fruits. In vitro propagation of apricot is very important for rapid multiplication of cultivars with desirable traits and production of cleaning up and virus-free plants. Low frequency of multiplication is the main limiting factor for traditional propagation methods. In this regard, the objective of our investigation was to study the morphogenetic capacity of apricot leaf explants of the promising cultivars ‘Iskorka Tavridy’, ‘Magister’ and ‘Bergeron’ for regeneration system development and solving some breeding questions. The source of explants was in vitro plants regenerated and cultured on QL medium. Leaves were maintained in the dark at 24±1 °C in thermostat for three-four weeks. Morphogenic callus and structures were mainly formed at the central and proximal parts of leaves on MS, QL and WPM media with 1.5 or 2.0 mg L-1 BAP and 1.5 or 2.0 mg L-1 IAA in different combinations, or TDZ (0.6 and 1.3 mg L-1). Callus with adventive buds was transferred to regeneration medium and placed into a growth chamber at 24±1 °C and 16-hour photoperiod with a light intensity of 37.5 μmol m-2 s-1. The best results were obtained when adaxial leaf surface was in contact with the culture medium. Frequency of leaf callus formation on MS medium with 1.5 mg L-1 BAP and 1.5 mg L-1 IAA was higher in the explants of ‘Iskorka Tavridy’ (80.0%) than in - ‘Bergeron’ (50.0%) and ‘Magister’ (36.7%). The best results of callogenesis for ‘Magister’ was obtained on MS medium with 1.3 mg L-1 TDZ (53.3%). Active microshoot regeneration in ‘Iskorka Tavridy’ cultivar was shown on MS medium with BAP and IAA and in ‘Magister’ cultivar - on MS medium with TDZ. Rhizogenesis was obtained on half strength MS medium with 2.0 mg L-1 IBA.