Shoot Formation Research Articles

Bioindication of the Dark Gray Soil State in the Pine Forests of the Krasnoyarsk Forest-Steppe under Anthropogenic Influence

The biological activity of dark gray soil was studied in a 100-year-old pine forb-green-moss forest of the Pogorelsky pine forest of the Krasnoyarsk forest-steppe. In 2017, selective cuttings were carried out in the pine forest, and in May 2022 there was a strong fire. To improve reforestation and increase the biological productivity of the soil, bio-fertilizer based on sawdust-soil substrate with the addition of urea and mycoproduct (SSSU + M) was applied to cut and burned areas. On the experimental plots (Paseka, Volok, Fon), an annual count of self-seeding of pine was carried out. Bioindication of the soil condition was assessed based on the total number and ratio of ecological-trophic groups of microorganisms, enzyme activity, microbial biomass content, intensity of basal respiration and specific respiration of microbial biomass. The application of biofertilizer to the cut areas alkalized the soil by 0.2–0.4 units, retained moisture, increased the content of nitrogen (by 5–14%) and microbial biomass (by 1.2–1.6 times), compared with the control options. The impact of biofertilizers on the germination and growth of self-seeding of pine was noted in the second year after application – in the experimental plots of self-seeding it was 4–6 times greater than in the control ones. The entry of burnt plant residues, coals and ash into the soil in the first week after the fire led to an increase in some microbiological indicators, the activity of urease and invertase, and the activation of carbotrophic microorganisms. However, by the end of the growing season, a decrease in microbiological activity was noted, which indicated a post-pyrogenic depression of microbocenoses. The introduction of biofertilizer on the burnt surface of the plots leveled the effect of pyrogenic effects and stimulated the formation of shoots of scots pine, the number of which was significantly higher than in the control plots. It was found that the universal bioindicators that adequately reflect the state of the soil after all anthropogenic impacts were microbial biomass, specific microbial respiration, enzymatic activity and the total number of microorganisms. A specific bioindication of the soil condition after the fire was an increase in the proportion of bacteria Serratia plymuthica, Bacillus mycoides and fungi of the genera Trichoderma, Penicillium and Mortierela.

РАЗМНОЖЕНИЕ ПОДВОЯ ВИШНИ АИ 70 В КУЛЬТУРЕ IN VITRO

The article presents the results of evaluating the effectiveness of clonal micropropagation of the clone rootstock of cherry AI 70 (FSBSI NCFSCHVW breeding). In the course of the research, the influence of the chelated forms of iron Fe-EDTA and Fe-EDDHA, as well as the concentration of 6 BAP (0.75 and 1.0 mg/l) on the efficiency of shoot formation was evaluated. We took the Murashige-Skoog medium as the basis. The greatest number of shoots in the rootstock AI 70 is formed on MS medium containing Fe-EDDHA (100 mg/l) and 6 BAP 1 mg/l. At the first passage, the multiplication factor is 5.2 shoots/exp., at the fourth passage the number of shoots increases to 12.3 pieces/exp. On average, 8.8 new shoots are formed for each passage. In the control variant on MS medium with Fe-EDTA, an average of 6.6 shoots/exp.

Effect of Different Hormones Concentration on In vitro Regeneration of Apricot Cultivars

The use of modern breeding methods along with appropriate cultivation techniques facilitates the acquisition and multiplication of varieties that possess the desired characteristics. Therefore, efforts towards the in vitro propagation of woody plants are increasing day by day. Today, plants such as Malus, Prunus, Pyrus, Ribes, Rubus, etc., can be successfully propagated in vitro. Apricot stands out as a stubborn species among Prunus types for shoot regeneration and genetic transformation. In this context, this study aims to determine how different plant growth regulators affect shoot regeneration of some native apricot varieties, which hold significant importance in apricot cultivation in our country. In the conducted study, mature cotyledons of Kabaaşı, Hacıhaliloğlu, and Hasanbey apricot varieties were used along with the culture medium consisting of MS. Different doses and ratios of plant growth regulators, including BAP and TDZ, in combination with NAA and GA3, were added to the culture media. At the end of the in vitro study, the callus and primordium formation rate (%), bud and shoot formation rate (%) and number of shoots per explant were recorded. According to the results, the variety with the highest callus formation was Kabaaşı, followed by Hasanbey and Hacıhaliloğlu. In all three varieties, the rate of callus formation decreased in media containing GA3. Regarding the stage of shoot regeneration from callus, the highest shoot formation with an average of 4 shoots per explant was observed in the Kabaaşı variety in the TDZ (1.0 mgL-1) + NAA (0.25 mgL-1) and TDZ (1.0 mgL-1) + NAA (0.50 mgL-1) media. Looking at the other varieties, the highest number of shoots, 1.6 shoots per explant, was obtained from the TDZ (2.0 mgL-1) + NAA (0.25 mgL-1) medium in Hasanbey and Hacıhaliloğlu varieties. As a result of the findings, the Kabaaşı variety showed the best result in terms of the regeneration capacity of apricot varieties. In contrast the best regeneration medium was obtained from the combinations of TDZ and NAA.

Improvements in Protoplast Isolation Protocol and Regeneration of Different Cabbage (Brassica oleracea var. capitata L.) Cultivars.

Protoplasts are a versatile tool in plant biotechnology since they can be used for basic biological studies as well as for breeding strategies based on genome editing. An efficient protoplast isolation protocol is essential for conducting protoplast-based studies. To optimize the protoplast isolation protocol in cabbage (Brassica oleracea var. capitata L.), different enzyme solutions were tested for the isolation of leaf mesophyll protoplasts. In our experiments, the combination of 0.5% Cellulase Onozuka RS and 0.1% Macerozyme R-10 showed the best result. The optimized protocol proved suitable for the isolation of protoplasts from five different cabbage cultivars with yields ranging from 2.38 to 4.63 × 106 protoplasts/g fresh weight (fw) and a viability of 93% or more. After three weeks in culture, protoplasts from all of the tested cultivars formed micro-calli, but further callus growth and shoot regeneration depended strongly on the genotype and regeneration protocol used. For shoot formation, 1 mg/L BAP in combination with auxin 0.2 mg/L NAA showed the best results with a regeneration of 23.5%. The results obtained will contribute to the development of different applications of cabbage protoplasts and facilitate the breeding process of this important horticultural crop.

Shoot regeneration in Nepenthes mirabilis as affected by flurprimidol and GA3 application

Abstract. Dwiati M, Widodo P, Susanto AH. 2023. Shoot regeneration in Nepenthes mirabilis as affected by flurprimidol and GA3 application. Biodiversitas 24: 4168-4174. Nepenthes mirabilis (Lour.) Druce. is a pitcher plant species at a higher risk of extinction mainly due to overexploitation. Previous investigations have shown that in vitro micropropagation can be used as an approach for ex-situ conservation of N. mirabilis. Therefore, this study aimed to assess the new shoot formation of N. mirabilis under in vitro conditions stimulated with the application of flurprimidol and GA3. The three concentrations of flurprimidol and GA3 used as treatments were arranged factorially in a Randomized Complete Block Design (RCBD), with internodes 2, 3, 4, and 5 serving as blocks. Based on the results, F1G0 (flurprimidol of 1 mgL-1 without GA3) had the highest shoot formation, which was not accompanied by sufficiently high contents of chlorophyll, leading to improper shoot development. Despite the smaller number of newly formed shoots in F2G2 (flurprimidol of 2 mgL-1 and GA3 of 2 mgL-1), significantly higher chlorophyll contents were observed, enabling better development of shoot. Leaf length and shoot diameter also showed similar results under F2G2, indicating that higher concentrations of exogenous GA3 were necessary for better shoot development. This indicated that appropriate concentrations of both plant growth regulators should be applied for micropropagation of N. mirabilis in support of ex-situ conservation.

Heat stress in wheat: a global challenge to feed billions in the current era of the changing climate

Crop failure is largely caused by various climate hazards, and among them, heat stress is the primary factor hindering crop production. The significant global loss of crop yield is primarily due to heat-related damage during the reproductive phase. Terminal heat stress has been well documented in wheat, causing morphophysiological alterations, biochemical disruptions, and reduction of genetic potential. The formation of shoots and roots, the effect on the double ridge stage, and early biomass in the vegetative stage are also impacted by heat stress. The final negative outcomes of heat stress include reduced grain number and weight, slower grain filling rate, reduced grain quality, and shorter grain filling duration. Plants have developed mechanisms to adapt to heat stress through modifications in their morphological or growth responses, physiological and biochemical pathways, and changes in enzyme reactions. Numerous heat tolerance genes have been identified in wheat, but the more extensive study is needed to increase heat tolerance in crops to satisfy the food demands of the world’s growing population. The global food policy needs to prioritize and promote additional joint research and the development of heat-tolerant wheat breeding to ensure the world’s food security.

Rhizome Segments Form Shoots, Whereas Leaf Cuttings Form Shoots and Rhizomes in Eucodonia ‘Adele’ Treated with Benzyladenine

Eucodonia ‘Adele’ initiates seasonal shoot growth from a scaly rhizome. Larger rhizome segments (>2.5 cm) produced shoots at a greater percentage compared with smaller rhizome segments. Shoots produced on larger segments were initiated sooner and had a longer length. However, when shoot formation efficiency was calculated as the number of potential shoots per original stock rhizome, smaller rhizome segments were more efficient, producing three to four times as many shoots. Rhizome segments (2.5 cm) soaked overnight in benzyladenine (BA) produced three to four times more shoots per rhizome (four shoots) compared with untreated or water-soaked rhizomes (0.3 and 0.7 shoot, respectively). The scaly rhizome consists of a central stem-like core surrounded by numerous leaf-like scales. Scales appear to be storage leaf tissue based on anatomy and presence of numerous amyloplasts. New shoots initiate as axillary shoots formed from the central core at the scale attachment. Isolated individual scales also have the capacity for adventitious shoot formation, but only form in about 25% of isolated scales. Leaf cuttings were capable of producing adventitious shoots, roots, and rhizomes. Untreated petiole and lamina cut leaf cuttings formed approximately three rhizomes per leaf cutting compared with less than one adventitious shoot per leaf cutting. Benzyladenine-treated leaf cuttings did not show an increase in rhizome initiation, but soaking lamina cut leaf cuttings in water or BA increased shoot formation to ∼1.5 shoots per cutting. This work with isolated rhizome segments and leaf cuttings presents efficient systems for regenerating rhizomes that can be used to produce stock plants for a stem cutting system for Eucodonia ‘Adele’ as a seasonal pot plant.

Comparative Seed Cryopreservation of Indonesian and New Zealand Epiphytic And Terrestrial Orchids

Background: The atypical seed storage behaviour reported in several orchid species justifies cryopreservation as a complementary conservation strategy to conventional seed banking. Objective This study aimed to assess the seed cryopreservation potential of five orchid species; tropical epiphytic, Indonesian species (Dendrobium strebloceras, D. lineale), one temperate New Zealand species (D. cunninghamii) and two temperate terrestrial, New Zealand species banksii, Thelymitra nervosa). MATERIALS AND METHODS: Seeds were cryopreserved direct immersion in liquid nitrogen (LN) and through the application of a cryoprotectant method. For the latter, seeds were exposed to Plant Vitrification Solution 2 (PVS2) for 0, 50, and 70 min, at either room temperature or on ice, prior to immersion in LN. RESULTS: Seeds all the studied species germinated well following direct cooling in LN. There was no difference in seedling development capability between cryopreserved and non-cryopreserved seeds of both epiphytic species and direct immersion in LN enhanced seed germination and shoot formation both temperate terrestrials. CONCLUSION: Through a range of analyses of germination and post-growth, our study shows the potential for cryopreserving epiphytic or terrestrial orchids tropical and temperate regions.

Transcriptome Revealed the Effect of Shading on the Photosynthetic Pigment and Photosynthesis of Overwintering Tea Leaves

The physiological state of overwintering tea leaves is crucial for the growth and quality formation of spring tea shoots. Low temperatures in winter can easily cause damage to overwintering tea plants, leading to leaf chlorosis and abnormal physiological functions. Many pieces of research have shown that shading could promote chlorophyll (Chl) accumulation in tea leaves, but the impact on overwintering tea plants is not yet known. In this study, different shading rates (no-shading, S0%; 30% shading, S30%; 75% shading, S75%) were used to treat overwintering tea plants, which explored the effect of shading on the color and physiological functions of tea leaves. The results showed that Chl, carotenoid, and soluble sugar (SS) contents were S75% > S30% > S0%, and the net photosynthetic rate (Pn) was S75% > S30% > S0%. Transcriptome analysis showed that the genes involved in chlorophyll and carotenoid metabolism (such as protochlorophyllide reductase POR and zeaxanthin epoxidase ZEP) and photosynthesis (such as photosystem II P680 reaction center D2 protein PsbA and photosystem II CP47 chlorophyll apoprotein PsbB) were significantly up-regulated under shading. In addition, many differentially expressed genes (DEGs) were enriched in “starch and sucrose metabolism (ko00500)” and “anthocyanin biosynthesis (ko00942)” pathways. In summary, this study provided a theoretical basis and technical support for maintaining green leaves and normal physiological functions of overwintering tea plants.

Development of an In vitro Propagation Protocol for Thalictrum foliolosum: An Endangered Medicinal Plant

The present study has developed a reproducible in vitro micropropagation protocol for endemic and endangered Thalictrum foliolosum by using leaf and root segments. Thalictrum foliolosum possesses high medicinal properties due to the presence of valuable phenols, flavonoids and alkaloids. The plants are uprooted due to their high medicinal and clinical applications, hence can lead to extinction threat. In vitro leaf and root, explant was used for induction of multiple shoots on MS medium supplemented with plant growth regulators like benzyl amino purine(BAP), indole-3- butyric acid (IBA), 1-Naphthalene acetic acid (NAA) and indole-3-acetic acid (IAA) alone or in combination. The best positive response for the formation of shoots from the leaf segment was obtained from MS media supplemented with BAP (1.0 mg/l) + NAA (0.6 mg/l) after 4 weeks and Maximum roots were formed on MS + IBA (0.6 mg/l) within 4-5 weeks. Likewise, the maximum percentage of shooting and rooting from root explant was obtained in MS + BAP (0.8 mg/l) + TDZ (0.4 mg/l) and MS + IAA (1.0 mg/l) + NAA (2.0 mg/l) after 4 weeks. The well-rooted acclimatized plantlets were successfully transferred to field conditions. Plant Tissue Cult. & Biotech. 33(1): 47-56, 2023 (June)

In vitro regeneration of hybrid Dendrobium sect. Spatulata through pseudobulb segment culture

The low rate of Dendrobium regeneration through seed culture is a significant limitation of mass propagation development in new hybrids. An efficient protocol of in vitro regeneration through pseudobulb segment culture has been established for Dendrobium ‘Danny Dame’. Leaves and roots of seven-month-old seedlings were detached from the pseudobulb. Unsegmented pseudobulb and segments of apical, medial, and basal excised from seedlings. The four types of explants were cultured on Murashige and Skoog (MS) basal medium supplemented with different combinations of 1-naphthaleneacetic acid (NAA) and 6-benzyl amino purine (BAP). The highest number of shoots was observed in 1 mg L-1 BAP and 0.1 mg L-1 NAA using unsegmented pseudobulb explant after 2 months of culture. The unsegmented pseudobulb had a higher survivability rate and the number of shoots per explant than segmented pseudobulbs. However, if accumulated, segmented pseudobulbs can produce the number of shoots 2-4 times more than unsegmented pseudobulbs. The segment that had the highest average number of shoots was the basal segment. Two types of shoots were observed, both single shoot and multi shoot. The new shoots formation was developed from protuberance and or axillary bud. Roots were kept to grow only on the basal part of unsegmented explants and basal segment.

A First Approach for the Micropropagation of the Edible and Medicinal Halophyte Inula crithmoides L.

Inula crithmoides L. (golden samphire) is an edible aromatic halophyte species with confirmed nutritional and medicinal properties attributed to the presence of important metabolites, including proteins, carotenoids, vitamins, and minerals. Therefore, this study aimed at establishing a micropropagation protocol for golden samphire that can serve as a nursery approach to its standardized commercial cultivation. For that purpose, a complete regeneration protocol was developed by improving shoot multiplication from nodal explants, rooting, and acclimatization methodologies. The treatment with BAP alone induced the maximum shoot formation (7-7.8 shoots/explant), while IAA treatment increased the shoot height (9.26-9.5 cm). Furthermore, the treatment that coupled best shoot multiplication (7.8 shoots/explant) and highest shoot height (7.58 cm) was MS medium supplemented with 0.25 mg/L BAP. Moreover, all shoots produced roots (100% rooting), and multiplication treatments did not exert significant effect on root length (7.8-9.7 cm/plantlet). Moreover, by the end of the rooting phase, plantlets cultivated with 0.25 mg/L BAP had the highest shoot number (4.2 shoots/plantlet), and plantlets from 0.6 mg/L IAA + 1 mg/L BAP presented the highest shoot height (14.2 cm) similar to control plantlets (14.0 cm). The survival up to the ex-vitro acclimatization stage was increased from 9.8% (control) to 83.3%, when plants were treated with a paraffin solution. Nevertheless, the in vitro multiplication of golden samphire is a promising way for its rapid propagation and can be used as a nursery method, contributing to the development of this species as an alternative food and medicinal crop.

In vitro direct organogenesis of the medicinal single-mountain local prioritized vulnerable Greek endemic Achillea occulta under different medium variants

Achillea species are of high medicinal value based on their use in traditional medicine and their content in secondary metabolites with potential application in dermatology and cosmetic industry. Achillea occulta is a single-mountain local prioritized vulnerable Greek endemic encountering propagation problems through seeds and root division. In vitro propagation can be used for the rapid and mass production of clonal plants complying with phytochemical and sanitary quality criteria. In this study, several culture medium variants were tested including the effect of different indole-3-butyric acid (IBA) concentrations with 6-benzyladenine (BA), different cytokinin types, agar concentrations, and zeatin (ZT) sterilization methods on in vitro shoot proliferation, as well as the effect of different auxin types and concentrations on in vitro rooting and ex vitro survival rate of shoot-tip explants. The results showed BA was the most preferable cytokinin type as evidenced by all proliferation attributes and autoclaved ZT provided longer shoots. Therefore, the two more promising and cost-effective treatments for proliferation were 2.2 μM BA + 0.25 μM IBA or 4.4 μM BA + 0.5 μM IBA after 21 days of culture on modified Murashige-Skoog (MS) medium (x2 Fe) enriched with 20 g L-1 sucrose and 6-7 g L-1 Agar (90-93.8% shoot formation, 2.7-2.9 shoots 0.4-0.6 cm long, 2.5-2.6 proliferation rates). Explants rooted better after 21 days of culture on plain MS medium with 2 μM IBA or 1 μM α-naphthalene acetic acid (NAA) (13.3-20% rooting, 1-1.5 roots 1.8-2 cm long). NAA gave more roots, IBA longer roots, while both auxins exhibited highest rooting (13.33-20%) and ex vitro survival rates (50-66.7%).

IN VITRO POTATO VARIABILITY AND ITS EFFECT ON TUBER NUTRITIONAL PROPERTIES

A comparative analysis of nine somaclonal Dutch selection “Alladin” potato variants test results was carried out using a modified Murashige-Skoog medium with different concentrations of hormones, vitamins and growth stimulants. As a result of the work carried out, 100% callus formation providing from leaf explants and more than 90% shoot formation without the use of additional steps associated with their rooting optimal protocols for in vitro cultivation of potatoes were defined. According to morphological characteristics 9 initial lines were selected among the Dutch selec-tion of “Alladin” potato variety regenerated plants using these protocols. The tubers of the second reproduction obtained from these lines were used for the analysis of bi-ochemical parameters (starch, soluble sugars, proteins). As a result, lines with the maximum starch content were identified, 2 lines out of 9 exceeded the control sample by 3.3% and 10.7%. The protein content in the tubers of 7 somaclonal variants from 1% to 10.6% exceeded this indicator in the control. In comparison to the control, the sugar content was significantly lower (from 37.9 to 54%) in 3 studied samples. The results obtained are of great practical interest for further breeding studies to consoli-date them and create new dietary and table varieties of potatoes. Based on the ob-tained somaclonal variants, new promising potato varieties adapted to the soil and climatic conditions of Northern Kazakhstan can be obtained.

Development of an Efficient and Rapid Micropropagation Protocol for In Vitro Multiplication of Maerua crassifolia Forssk

The difficult propagation of shrub and tree species and their extensive exposure to grazing threaten their abundance and lead to the necessity to find alternative means of propagation for these species. In vitro micropropagation techniques, viz., tissue culture, offer a promising tool for the rapid, cost-effective, and efficient propagation of different plant species. In the current study, a rapid and efficient in vitro multiplication protocol was developed for the micropropagation of Maerua crassifolia Forssk. Our results revealed that Murashige and Skoog (MS) medium with 7.5 µM of 6-benzylaminopurine (BA) and 1.0 µM of 1-naphthaleneacetic acid (NAA) led to the highest shoot formation (13.9 shoots per explant in 85.7% of the cultivated hypocotyls) among all other treatments. The best in vitro root formation was obtained on half-strength MS medium with 1.0 µM of indole 3-butyric acid (IBA) as 94.1% of the cultivated shoots formed 6.8 roots per microshoot on average. Ninety percent of the rooted plantlets were successfully acclimatized and are currently growing in the botanical garden of the Botany and Microbiology Department, King Saud University, Riyadh, Saudi Arabia. The genetic fidelity of the micropropagated plants was authenticated via flow cytometry. The results of the current study explained a simple, cost-effective, and efficient protocol for the micropropagation of the endangered M. crassifolia trees.

Gamma Irradiation Effect on the Callus Growth and Shoot Regeneration of Pogostemon cablin Benth.

Abstract. Patchouli is an essential producer of patchouli oil in the perfume industry, and its production needs to be increased to meet market demand. In vitro mutagenesis using gamma irradiation has the potential to produce superior patchouli plants. This study aimed to evaluate the effect of gamma irradiation on callus growth and shoot formation on patchouli callus. Calli were gamma-irradiated at doses of 0, 15, 30, 45, 60, and 75 Gy, then cultured on Murashige and Skoog (MS) medium with the addition of 0.1 mg.L-1 NAA and 0.3 mg.L-1 BA for four weeks. The results showed that gamma irradiation inhibited callus growth and shoot formation. Gamma irradiation increased the percentage of explant browning and decreased explant survival, explant formation of shoots, the total number of shoots, number of shoots/explants, fresh weight of callus and shoots, growth index, and growth rate. The higher the dose of gamma irradiation, the smaller the percentage of explant survival and the lower the ability to form shoots with an average number of shoots formed less. The percentage of explants that survived on callus without irradiation and at a low dose of 15 Gy reached 100%, with an average number of shoots formed between 4.34-5.63 shoots/explant. Meanwhile, the percentage of explants that survived at high doses of 60-75 Gy was 76-82%, with an average number of shoots formed about two shoots/explant. The lethal dose (LD20) for explant survival was 67.98 Gy.

Beneficial Effect of the New Leptodophora sp. Strain on Development of Blueberry Microclones in the Process of Their Adaptation.

The paper searches for new solutions for the development of highbush blueberry orchards (Vaccinium corymbosum L. (1753)) in Western Siberia. All species of the genus Vaccinium display special symbiotic mycorrhizal associations with root systems-ericoid mycorrhiza, which essentially enhances the formation of adventitious and lateral roots. For the first time, we obtained pure cultures of micromycetes associated with the roots of wild species of the family Ericaceae in the Tomsk region, Russia. With regard to the data of molecular genetic analysis of the ITS region sequence, we selected the BR2-1 isolate based on its morphophysiological traits, which was assigned to the genus Leptodophora. Representatives of this genus typically enter into symbiotic relationships with heathers to form ericoid mycorrhizae. We studied the effect of strain BR2-1 on the development of microclones of the highbush blueberry var. Nord blue during their in vitro adaptation and showed its beneficial effect on growth and shoot formation in young plants. Experiments performed using submerged and solid-state methods showed that the most optimal method for commercial production of BR2-1 is cultivation on grain sterilized by boiling, followed by spore washing.

In vitro shoot formation and enrooted mini-corm production by direct organogenesis in saffron (crocus sativus L.)

In vitro shoot formation and enrooted mini-corm production by direct organogenesis in saffron (crocus sativus L.)

Clonal micropropagation of rocket (Eruca sativa Mill.)

Purpose. To optimize the method of clonal micropropagation of rocket (Eruca sativa Mill.). Methods. Seeds of rocket cultivars 'Znahar' and 'Lybid' were used for introduction into in vitro culture. Solutions of sodium hypochlorite (35%), ethanol (70%) and HgCl2 (0.2%) were used for sterilization. A 5% solution of chloramine served as a control. Sterile material was planted on liquid and solid agar nutrient media according to Murashige-Skoog (MS) and Hamborg-Eveleg (B5). A solid nutrient medium MS supplemented with 0.5 mg/l BAP was used as a control at all stages of reproduction. 6–benzylaminopurine (BAP), benzylaminopurine (BA), kinetin, IAA, NAA and IBA were added to media for reproduction and rooting. The control was IAA (0.5 mg/l). Results. Sterilization of seeds with HgCl2 resulted in obtaining 93 and 90% sterile material; however, no viable seeds were found. The highest indicators of material sterility in the studied rocket varieties were noted for the use of sodium hypochlorite solution: in 'Znahar' 93% and 'Lybid' 89%. In addition, viability in this treatment was at the level of 90 and 85%, respectively. Higher indicators of both the number of shoots (8 and 6) and their height (8 and 3 cm) of both studied varieties were obtained on the MS medium (medium B5 – 5 and 5 shoots, and 5 and 4 cm, respectively). The most intensive shoot formation occurred with the use of kinetin. In particular, on the MS medium, variety 'Znahar' formed 19 shoots, 'Lybid' 17 shoots; on B5 – 16 and 13 shoots, respectively. At a concentration of 0.8 mg/l, the length of the shoots of the studied varieties was with IAA 10 and 8 cm, with NAA 15 and 13 cm and with IBA 18 and 16 cm, respectively. The same tendency was observed when the concentration increased to 1.2 mg/l. The number of lateral roots varied from 3 to 7 in the control and from 4 to 11 in the experimental treatments. Most of the roots were formed at an IBA concentration of 1.2 mg/l. In the case of adding 0.8 mg/l of NAA, 7 roots were formed in 'Znahar' and 5 in 'Lybid'; when increasing the concentration to 1.2 mg/l the number was 10 and 9, respectively. Conclusions. The worst indicators of viable seed material were obtained after sterilization with a HgCl2 solution (93 and 90% of sterile and 0% of viable seeds) and the best with sodium hypochlorite solution (93 and 89% of sterile and 90 and 85% of viable seeds). On the liquid nutrient media according to different prescriptions, the smallest indicators of the height of shoots and their number were obtained. Also, in these treatments, the vitrification of plants, their slow growth and insignificant shoot formation were observed. The longest root system was formed in the studied rocket varieties with adding IBA to the nutrient medium. At the same time, under such conditions, regardless of the IBA concentration, plants formed too long root system that can be injured during planting; therefore, it is more appropriate to use IAA and NAA or their combination.

Changes in the expression pattern of OsWUS negatively regulate plant stature and panicle development in rice.

WUSCHEL (WUS) and WUSCHEL-RELATED HOMEOBOX (WOX) encode transcription factors and play important roles in regulating the formation and maintenance of shoot and floral meristems. OsWUS have distinct functions in meristem development with slightly tuned expression. However, the mechanisms regulating the specific expression of OsWUS need to be further explored. In this study, an abnormal expression mutant of OsWUS, called Dwarf and aberrant panicle 1 (Dap1) was used. In order to identify the causal gene in Dap1, high-efficiency thermal asymmetric interlaced (hiTAIL)-PCR and co-segregation analysis were performed. We surveyed the growth and yield traits in Dap1 and wild type. Changes in gene expression between Dap1 and wild type were determined by RNA-seq. The Dap1 mutant is due to the T-DNA inserted at 3,628-bp upstream of the translation start codon of OsWUS. Plant height, tiller numbers, panicle length, the number of grains per main panicle, and the number of secondary branches was significantly reduced in the Dap1 mutant. The expression of OsWUS was markedly increased in Dap1 mutant plants compared to the wild type, which might be due to a disruption in the genomic sequence integrity. Simultaneously, the expression levels of gibberellic acid-related genes and genes involved in panicle development were significantly changed in the Dap1 mutant. Our results suggest that OsWUS is a precise regulatory element, its specific spatio-temporal expression pattern is critical for its function, and both loss-of-function and gain-of-function mutations lead to abnormal plant growth.