Concentrations Of Growth Regulators Research Articles

Optimizing PGRs for in vitro shoot proliferation of pomegranate with bayesian-tuned ensemble stacking regression and NSGA-II: a comparative evaluation of machine learning models

BackgroundThe process of optimizing in vitro shoot proliferation is a complicated task, as it is influenced by interactions of many factors as well as genotype. This study investigated the role of various concentrations of plant growth regulators (zeatin and gibberellic acid) in the successful in vitro shoot proliferation of three Punica granatum cultivars (‘Faroogh’, ‘Atabaki’ and ‘Shirineshahvar’). Also, the utility of five Machine Learning (ML) algorithms—Support Vector Regression (SVR), Random Forest (RF), Extreme Gradient Boosting (XGB), Ensemble Stacking Regression (ESR) and Elastic Net Multivariate Linear Regression (ENMLR)—as modeling tools were evaluated on in vitro multiplication of pomegranate. A new automatic hyperparameter optimization method named Adaptive Tree Pazen Estimator (ATPE) was developed to tune the hyperparameters. The performance of the models was evaluated and compared using statistical indicators (MAE, RMSE, RRMSE, MAPE, R and R2), while a specific Global Performance Indicator (GPI) was introduced to rank the models based on a single parameter. Moreover, Non‑dominated Sorting Genetic Algorithm‑II (NSGA‑II) was employed to optimize the selected prediction model.ResultsThe results demonstrated that the ESR algorithm exhibited higher predictive accuracy in comparison to other ML algorithms. The ESR model was subsequently introduced for optimization by NSGA‑II. ESR-NSGA‑II revealed that the highest proliferation rate (3.47, 3.84, and 3.22), shoot length (2.74, 3.32, and 1.86 cm), leave number (18.18, 19.76, and 18.77), and explant survival (84.21%, 85.49%, and 56.39%) could be achieved with a medium containing 0.750, 0.654, and 0.705 mg/L zeatin, and 0.50, 0.329, and 0.347 mg/L gibberellic acid in the ‘Atabaki’, ‘Faroogh’, and ‘Shirineshahvar’ cultivars, respectively.ConclusionsThis study demonstrates that the 'Shirineshahvar' cultivar exhibited lower shoot proliferation success compared to the other cultivars. The results indicated the good performance of ESR-NSGA-II in modeling and optimizing in vitro propagation. ESR-NSGA-II can be applied as an up-to-date and reliable computational tool for future studies in plant in vitro culture.

Influence of Gibberellic Acid Growth Regulator on Sunflower Seed Emergence Indices and Seedling Characters under Salinity Stress

Salinity stress is one of factors limiting seed germination and seedling development in sunflower at New halfa scheme in East of Sudan. The objective of this study was evaluation germination indices and seedling parameters of sunflower seed under salinity stress with varying concentrations of synthetic growth regulator namely GA3. From 16-30 November 2019 a laboratory experiment (in Petri dishes) of randomized complete blocks design (RCBD) with three replicates was carried out. Treatments were consisted of (four levels of GA3 were 0, 50,75 and 100 p.pm) designated as G0,G50,G75 and G100,respectively, under five levels of salinity (0, 0.5, 1.0, 1.5 and 2%) designated as Na0, Na1.0 ,Na1.5 and Na2.0. This study examined Emergence indices: Seed Emergence percentage EP%, Mean emergence time (MET), Mean daily germination (MDG), Energy of germination was( EE), Emergence index(EI), Daily germination speed (DGS), Emergence coefficient of uniformity (ECU), vigour index of seed(VIS) and seedling characters also were determined. The results indicated that application of GA3 at 50 p.pm resulted in high EP, MDG, MET and SVI as compared with other related treatments. Also application of (G75 and G100) resulted in higher values of DGS, ECU and EI. Application of high levels of salinity treatments resulted in decreasing of all germination indices in this study. The interaction treatment ( G50xNa0) on MDG had significant differences in this study. In condition, GA3 increasing up germination indices and promoting growth and compromised seedling vigor while salinity hindered seed emergence and seedling characters of sunflower.

Germination Indices and Seedling Growth Parameters in Maize under Salinity Stress with Varying Concentrations of Giberellic Acid (GA)

Salinity stress is one of the factors limiting seed emergence and seedling development in sunflower at New halfa scheme in East of Sudan. A study of two factors pots experiment was conducted during winter season of 2019 to evaluate germination indices and seedling growth characters of maize seeds under salinity stress with varying concentrations of synthetic growth regulator namely (GA3). The experiment was laid out according RCBD with three replications. Treatments consisted of five levels of salinity (0, 0.5, 1.0, 1.5 and 2% ) designated as Na0, Na0.5, Na1.0 ,Na1.5 and Na2.0, and four levels of GA3 were (0, 50,75 and 100 p.pm) designated as G0, G50, G75 and G100, respectively,. The studied parameters include germination indices; daily germination (MDG), daily germination speed (DGS), final germination percentage (FGP), mean emergence time (MET), mean Energy of germination (EE), emergence index (EI), coefficient of uniformity of emergence (CUE) and vigour index (SVI). Also, seedling fresh and dry weight, shoot length and root length were measured, and the shoot/root ratio was calculated. The negative effects of salinity stress significantly decreased germination indices and seedlings growth characters in a dose dependent manner. The results showed that, application of GA3 at medium levels concentration (specify those doses) increased all studied parameters. In conclusion, application of high Ga3 levels enhanced all germination indices and seedlings growth characters while high salinity levels reduced these traits of maize seeds. Such result has made the base for further study that should be conducted in different seasons with different growth regulators involving different parameters of other crops.

Response of Dragon Fruit (Hylocereus sp.) Cuttings to Different Plant Growth Regulators.

Dragon fruit (Hylocereus sp.) is an exotic crop with a great potential for its cultivation in semi arid tracts throughout India. Its planting is mainly confined to harsh climates and degraded lands facing challenges in its establishment. Hence, availability of quality planting material is essential for attaining success. Due to long juvenile phase of the sexually propagated seedlings it can be propagated asexually by stem cuttings but proper rooting is not possible without exogenous auxin application. Hence, during 2022-2023 a research was carried out at the Horticultural Experimental area of Khalsa College, Amritsar to standardize the concentration of plant growth regulators viz. IBA, NAA and PHB for rooting and success rate in stem cuttings comprising of sixteen treatments with three replications arranged in randomized block design. The results revealed that the stem cuttings treated with IBA 4000 ppm proved to be superior for the sprouting and survival of the cuttings resulting in the improved vegetative growth with profuse, longer, thicker and the heaviest roots. Hence, the cutting treatment of IBA 4000 ppm can be proposed for dragon fruit plant propagation to meet the market demand in India.

Development of a Micropropagation Protocol for the Ex Situ Conservation of Nuttall's Scrub Oak (Quercus dumosa).

Worldwide, oak species are threatened with extinction due to habitat loss, pathogens, and changing fire regimes. Ex situ conservation through tissue culture may protect the remaining genetic diversity of Quercus dumosa, or the coastal sage scrub oak, from further loss. We designed three basal salt formulations based on the mineral composition of shoot tips and first leaves from mature Q. dumosa and explored carbohydrate source, stress-mitigating compounds, and plant growth regulator concentrations to develop a method of cultivating many Q. dumosa culture lines in vitro. All three novel basal salt formulations led to decreased necrosis compared with commercial basal salt formulas WPM, MS, and DKW. Substitution of 30 g L-1 sucrose with glucose and adding 250 mg L-1 ascorbic acid, 5.2 mg L-1 SNP sodium nitroprusside, and 103 mg L-1 y-aminobutyric acid improved culture health overall. In an experiment involving 115 culture lines, 0.66 mg L-1 6-benzylaminopurine produced the highest average shoots per explant, but 0.33 mg L-1 produced the greatest proportion of shoots 2 cm or greater. Incubation for 24 h in 20 mg L-1 indole-3-butyric acid led to the most rooting. These methods show promise for the ex situ conservation of many genotypes of endangered Q. dumosa.

PENGARUH PEMBERIAN ZAT PERANGSANG TUMBUH TERHADAP PERTUMBUHAN BIBIT TANAMAN GAHARU (Aquilaria malaccensis Lamk) DI POLYBAG

This research was carried out in Penginjau Hamlet, Bathin II Pelayang District, Bungo Regency, at an altitude of ± 75 meters above sea level. The research was carried out from 05 January 2015 to 05 April 2015. This research aims to study to determine the effect of giving growth stimulants on the growth of gaharu plant seeds (Aquilaria malaccensis Lamk) in polybags. The aim of the research is to obtain a dose of growth stimulants that will give results to the growth of agarwood seedlings.The method used in this research was a completely randomized design (RAK), with 5 treatments and 4 replications. The concentration of Atonic growth stimulant used was as follows: A0: No treatment (as control), A1: 0.50 cc Atonic ZPT/liter of water , A2: 1.00 cc ZPT Atonik/ liter of water, A3: 1.50 cc ZPT Atonik/ liter of water and A4: 2.00 cc ZPT Atonik/ liter of water. The data obtained from the final observations were analyzed using variance, if they had a real effect then continued with the Duncan New's Multiple Range Test (DNMRT). The variables observed were plant height (cm), total leaf area (cm2), stem diameter (mm) and root volume (ml). From the experimental results, the administration of atonic plant growth regulator (ZPT) concentrations had no significant effect on plant height (cm), total leaf area (cm2), stem circumference (mm) and root volume (ml)

High frequency in vitro multiplication of polygonatum verticillatum (l.) All. From rhizome bud explants

This work aims to develop a rapid protocol for the in vitro establishment of Polygonatum verticillatum (L.) All., an astounding medicinal herb of Astavarga group of plants. Successful in vitro establishment was achieved utilizing rhizome bud segments of approx. 0.5 to 1.0 cm size as explants. Sterilized explants were cultured on MS medium containing graded concentration of different plant growth regulators used either singly or in various combinations. Maximum (85±10.0%) per cent shoot induction with maximum shoot length (6.50 ± 0.11cm) were recorded in TDZ (2.0 mg/l) + NAA(1.0 mg/l) + GA3 (2.0 mg/l) supplemented MS medium. NAA (1.0 mg/l) + Kn (0.5 mg/l) and IBA(1.0 mg/l) supplemented full strength MS medium with 3% sugar showed highest 70 ± 5.0% rooting response.½ MS+1.5 % sucrose medium augmented with IBA (1.0mg/l) showed the maximum average number of roots per explants (12.8 ± 1.07) with highest root length(6.12±0.27 cm). After hardening plantlets were transferred to pots in glasshouse produced healthy plants with 56% survival rate. Bangladesh J. Bot. 53(1): 203-208, 2024 (March)

Improvement of the potato seed production system on a virus-free basis in Almaty region

This article presents data on the induction of potato microtubers and the potency of different varieties to form microtubers in vitro. It has been established that the main factors influencing the process of tuberization in potato regenerated plants are: the concentration of carbohydrates and plant growth regulators in the nutrient medium and physiological state. Experiments were carried out to obtain microtubers from regenerated plants of 4 potato varieties of domestic selection (Alliance, Babaev, Miras and Pamyaty Konaeva) for the selection of virus-free primary material for seed production.As a result, a modified nutrient medium Murasige and Skoog (MS) containing 20 mg/L orotic acid was developed to accelerate the formation of microtuber formation of potato plants in vitro.

Клональное микроразмножение лесных ягодных растений рода Rubus

Cloudberry (Rubus chamaemorus L.) and arctic raspberry (Rubus arcticus L.) are highly nutritional and medicinal but lowyield berries, with some populations being on the verge of extinction. Micropropagation biotechnologies are cost-effective and may provide healthy and plentiful planting material for these valuable berries. Clonal micropropagation of cloudberry and arctic raspberry requires new methods adapted for Russian varieties. This research featured the effect of sterilizing agents on the survival rate of explants of R. chamaemorus and R. arcticus, as well as the effect of growth regulators in the nutrient medium on their organogenesis in vitro.
 Berries obtained from regenerant plants of R. chamaemorus (Arkhangelsk and Vologda varieties) and R. arcticus (Sofia and Galina varieties) underwent a biochemical analysis. Further research involved the effect of sterilizing agents and exposure time on the viability of explants, as well as the effect of the nutrient medium composition and the concentration of growth regulators on the development of microshoots and roots in vitro.
 In case of lateral buds, the highest survival rate of both types of explants (80–96%) belonged to the samples sterilized with 0.2% silver nitrate and 5% Lysoformin 3000 for 15 min. In case of etiolated shoots (79–100%), it was the samples treated with 0.2% silver nitrate, 0.01% Nika 2, and 5% Lysoformin 3000 for 10 min. The maximal total length of microshoots in R. chamaemorus (19.4–22.7 cm) was registered at 0.1 mg/L Cytodef in the Murashige and Skoog medium. The maximal total length of roots (46.0–56.6 cm) was obtained when the medium contained 0.5 mL/L indolylacetic acid. As for R. arcticus, the maximal total lengths of microshoots (22.4–22.8 cm) and roots (86.6–89.3 cm) occurred at the same concentrations of growth regulators on 1/2 Murashige and Skoog medium.
 In this research, Cytodef and indolylacetic acid applied in the process of clonal micropropagation of R. chamaemorus and R. arcticus made it possible to increase the yield of high-quality planting material for commercial plantations.

Growth, vegetative rescue and vegetative propagation in Eucalyptus species and hybrids

The objective of the study was the evaluation of survival and productivity indicators in different species/hybrids of Eucalyptus in the adult stage, as well as the vegetative rescue of adult trees and cuttings, testing for species/hybrids, concentration of growth regulator and substrates in rooting. In the evaluation of species/hybrids, height (m), diameter at breast height (DBH, cm) and individual volume (m3 per individual) were measured, and survival was evaluated. In the vegetative rescue treatment, the number of shoots produced at 90, 120 and 210 days was evaluated. In the cutting experiments, the species that produced rescue shoots were tested, in addition to indole-3-butyric acid (IBA) doses (0, 1 500, 3 000 and 4 500 mg L−1) and four substrates for rooting cuttings. The experiments of IBA doses and substrates were carried out using Eucalyptus saligna plants. In the cutting experiments, after 120 days of cultivation, the following variables were evaluated: callus formation (%), survival (%), rooting (%), number and length of roots. The best results regarding survival and quantitative variables of the species/hybrids were obtained for E. dunnii, E. dunnii × E. grandis and E. pellita. In the vegetative rescue, E. dunnii × E. grandis and E. pellita had the highest formation of shoots and the girdling vegetative rescue method had the best results in terms of generated shoots. E. saligna had better results regarding the variables related to the rooting of cuttings. The substrate S3 and the use of 1 500 mg L−1 of IBA provided the highest survival rate and better variables related to the rooting of the cuttings.

Induction, Proliferation and Differentiation of Callus in Paris polyphylla Sm. through Leaf Culture

Paris polyphylla Sm. is a vulnerable medicinal plant employed in the treatment of various ailments. This study seeks to establish a protocol for callus induction, proliferation, and differentiation of P. polyphylla. Immature leaf explants were cultured on MS medium with varying concentrations of plant growth regulators (PGRs), including 2,4-dichlorophenoxyacetic acid (2,4-D), kinetin (Kn), 6-benzylaminopurine (BAP), Thidiazuron (TDZ), α-Naphthalene acetic acid (NAA), and Gibberellic acid (GA3), along with 10% coconut water. After 12 weeks of primary culture, the optimal callus induction was observed in MS medium supplemented with 0.25 mg/l 2,4-D + 0.5 mg/l Kn. In the secondary culture at 8 weeks, the best callus proliferation, as determined by callus weight or growth index, occurred in MS medium supplemented with 2.0 mg/l BAP alone, 2.0 mg/l Kn alone, 1.0 mg/l TDZ alone, combinations of 2.0 mg/l Kn + 1.0 mg/l BAP + 2.0 mg/l GA3, and combinations of 0.5 mg/l NAA + 2.0 mg/l BAP + 2.0 mg/l GA3, as well as 10% coconut water. Furthermore, callus differentiation into mini rhizomes with root primordia was successfully achieved in MS media containing 2.5 mg/l Kn and 10% coconut water. This study reports, for the first time, the formation and differentiation of callus from leaf explants in P. polyphylla. Large-scale callus generation from leaf explants has the potential to enhance the production of bioactive secondary metabolites for therapeutic purposes and facilitate the development of plantlets through organogenesis.

Direct Organogenesis of Citrus Cultivars from Shoot Tip Nodal Segments.

Citrus cultivar improvement via conventional breeding strategies is impeded by factors related to its reproductive biology. The orange is a hybrid between pomelo (Citrus maxima) and mandarin (Citrus reticulata). Among various orange cultivars, Valencia oranges have a bit of bitter tang mixed in with their sweetness, as Navel oranges are, the most widely cultivated citrus species, quite sweeter, and also don't contain any seeds. Tangelo mandarin orange cultivar is a hybrid of C. reticulata × C. maxima or × C. paradisi. The present study was undertaken to optimize the hormonal composition of the media with regard to plant growth regulators for in vitro propagation of sweet orange cultivars from nodal segment explants. The nodal segment explants were collected from three citrus cultivars, Washington Navel, Valencia and Tangelo. Murashige and Skoog (MS) medium supplemented with sucrose and different concentrations of growth regulators was used for shoot proliferation and root induction, and the optimum medium composition was assessed. The patent for Citrus Tissue Culture was obtained from the Office of Research Affairs, Haramaya University. The results indicate that the highest shoot response was recorded for Washington's navel with maximum shoot proliferation rate (99.75%), shoot number per explant (1.76), shoot length (10.70 cm), leaf number per explants (3.54) after three weeks of culture. In all experiments, no growth was observed for the basal MS medium. Phytohormone combinations of IAA (1.2 mg/L) and kinetin (2.0 mg/L) were found to be the best for shoot proliferation. Among the cultivars, there were significant differences for the highest rooting rate (81.255), root number (2.22), and root length (2.95 cm) variables for Washington Navel. The lowest rooting rate (48.45%), root number (1.47) and root length (2.26 cm) were observed for Valencia. The highest rooting rate (84.90%), root number per microshoot (2.22) and root length (3.05 cm) was on MS medium supplemented with 1.5 mg/L NAA. A comparison of different concentrations of IAA and NAA on root induction of microshoots from nodal segments of citrus cultivars demonstrated NAA was a more effective hormone than IAA.

Factors Affecting the Micropropagation of Sapindus trifoliatus from Nodal Explants of Mature Tree

Background:: Explant recalcitrance is one of the major challenges during the tissue culture of a tree species, especially when explants are derived from mature plants. It is mainly as-sociated with the genotypes/species, source and physiological status of explants, seasonal variations, and competency/incompetency of explants towards PGRs for in vitro manipulations. There-fore, to optimize the appropriate conditions and minimize explant recalcitrance, it is necessary to elucidate the different factors influencing the tissue culture of a tree species. Objective:: Several factors influencing in vitro shoot induction from nodal explants derived from mature plants of Sapindus trifoliatus were investigated. Methods:: Nodal segment obtained from mature plants was used as an explant for shoot regeneration. The factors assessed in this study included the types and concentrations of plant growth regulators, nutrient composition of MS (Murashige and Skoog) medium, sucrose concentrations, the position of nodes on their respective branches, seasonal variations, and successive transfers of mother explant. Results:: The performance of nodal explants was better on modified MS medium, i.e., M4 medium (half-strength of MS major salts and full-strengths of MS minor salts, Fe-EDTA and MS organic nutrients each) than the full-strength MS medium. The addition of BAP in the medium resulted in a higher shoot induction rate than other cytokinins i.e., Kin, Zeatin, TDZ. M4 medium supplemented with 3.0 mg l-1 BAP and 2% sucrose was optimum for shoot proliferation. However, elongation of shoots was observed only when induced shoots, along with the mother explant, were subcultured on a medium containing 1.0 mg l-1 BAP. The shoot multiplication was positively affected by the repeated transfer of the mother explant for different passages on the multiplica-tion medium. Mother explant transferred to multiplication medium (0.8% agar-solidified M4 medium + 2% sucrose + 1.0 mg l-1 BAP) proliferated maximum shoots after fourth passages. Regenerated shoots were rooted in vitro and further successfully acclimatized in field conditions. Conclusion:: The in vitro regeneration system developed from an explant obtained from mature trees can be successfully exploited for mass multiplication of Sapindus trifoliatus, a medicinally and commercially important tree.

In vitro propagation, cold preservation and cryopreservation of Taxus baccata L., an endangered medicinal and ornamental shrub

In vitro propagation, cold preservation, and cryopreservation are three essential approaches to preserve the genetic resources of red-listed plants, including English yew (Taxus baccata L.). Different concentrations of plant growth regulators (PGRs) and different pre-treatments of cold preservation and cryopreservation are the prerequisites of these three approaches. Apical bud as explant and Murashige and Skoog (MS) as the culture medium for all three sections of the research, kinetin (Kin) and indole-3-butyric acid (IBA) as PGRs for the micropropagation section, and encapsulation-dehydration as pre-treatment for the sections of cold preservation and cryopreservation were used. The results of the micropropagation section indicated that the highest number of shoots (5.40 per explant) and roots (5.98 per explant) were obtained from the culture of the explants on the media containing 1 mg L–1 IBA together with 1 and 2 mg L–1 Kin, respectively. The results of the cold preservation section revealed that the highest percentage of survival of germplasms (100%) after storage in the refrigerator was observed in the apical buds pre-treated by dehydration of encapsulated explants with 0.75 M sucrose for two hours, followed by dehydration under a laminar airflow cabinet for two hours. The results of the cryopreservation section demonstrated that the highest percentage of survival of germplasms (100%) after storage in liquid nitrogen was obtained in the apical buds pre-treated by encapsulation-dehydration under a laminar airflow cabinet for two hours. At the acclimatization stage, 100% of the plantlets acclimatized suitably with ex vitro conditions.

Influence of different factors on in vitro multiplication and rooting of three local Juglans regia L. genotypes in Uzbekistan

The Persian walnut (Juglans regia L.) is one of the most lucrative and widely distributed nut crops. It is appreciated as a forestry and ornamental tree in addition to its benefits as a fruit crop. Although Central Asian countries, especially Uzbekistan, are among the origins of the Persian walnut; they are not considered as top industrial producers of walnuts. Uzbekistan possesses a wide range of walnut genetic resources and as a result of conducted research, several promising, fruitful, early-harvesting varieties and forms have been selected. The aim of this study is to optimize microclonal in vitro propagation of selected Uzbekistan local varieties and forms by evaluating concentrations of different plant growth regulators and genotype on multiplication and rooting stages. As mother plants, 2 forms and one variety were selected: the Ideal variety, 'Form PDM23' and 'Form 202YaKT'. ?n the proliferation stage, the growth rate of walnut microshoots on basal medium Driver and Kuniyuki Walnut Medium (DKW) with different concentrations of 6-benzylaminopurine (BAP) and Indole-3-butyric acid (IBA) (0.01 mg/L) was studied. The rooting stage was assessed in half strength macronutrient DKW medium containing different IBA concentrations (0.0, 2.0, 4.0 and 6.0 mg/L). The Ideal variety and 'Form PDM23' performed best in DKW medium supplied with 1.5 mg/L BAP and 0.01 mg/L IBA, whereas 'Form 202YaKT' performed best in DKW medium supplemented with 1.0 mg/L BAP and 0.01 mg/ L IBA for the proliferation stage. For all genotypes, 6.0 mg/L IBA provided the best rooting results.

Prohexadione-Calcium Mitigates the Overgrowth of Corn Seedlings

In the temperate climate of South Korea, specific corn varieties are cultivated using plug trays. The cultivation process is initiated from February to March within greenhouse facilities, maintaining a temperature below 10 degrees Celsius. Following this, in April, seedlings are transplanted to enable an exceptionally early harvest for increased profitability. However, the subsequent elevation in indoor temperatures leads to seedling overgrowth. This study explores the effectiveness of three plant growth regulators—paclobutrazol, prohexadione-calcium, and diniconazole–on super sweet corn seedlings. Significantly, the application of prohexadione-calcium at 2 ppm during the first leaf stage substantially reduces seedling height and impedes the growth of both the first and second internodes. This impact extends to leaf-related traits, manifesting reductions in the area, length, and width of the third leaf. Furthermore, prohexadione-calcium induces a significant decrease in both fresh and dried shoot weight, while simultaneously augmenting root weight. This alteration results in a noteworthy shift in the root–shoot ratio, particularly at 2 ppm. Subsequent experiments have identified the optimal concentration of prohexadione-calcium at 15 ppm, effectively mitigating overgrowth in both hybrid and inbred corn varieties. These findings provide essential insights for practitioners seeking to efficiently manage corn seedling overgrowth. The study contributes to understanding the retardant effect of prohexadione-calcium on various morphological traits, offering practical applications for optimizing plant growth regulator concentrations in corn cultivation strategies.

Development and Optimization of a Rapid In Vitro Micropropagation System for the Perennial Vegetable Night Lily, Hemerocallis citrina Baroni

The perennial herbaceous night lily, Hemerocallis citrina Baroni, is an important vegetable crop with an increasing production and consumption in China. The long lifecycle and slow growth of the night lily are becoming bottlenecks for the large-scale production of elite lines and various genetic and breeding studies. There is a lack of a protocol for rapid and efficient micropropagation for this crop. Here, we reported the systematic investigation and optimization of in vitro plant regeneration through tissue-culture-based organogenesis in the night lily variety ‘Datong Huanghua’. We evaluated various factors affecting the efficiency of callus induction and subculture, shoot regeneration, rooting and plantlet establishment, including explant type and age, inoculation methods, basal culture media and the type and concentration of plant growth regulator (phytohormones) in various growth media. We developed an optimized protocol, as follows. The highest efficiency of callus induction was observed on Murashige and Skoog (MS) medium supplied with 22.7 µM TDZ (thidiazuron) using the young scape (flower stem or stalk) as the explant, which was cut longitudinally in half to produce a segment approximately 0.5 cm in length. Callus subculture and proliferation were more efficient on MS medium containing 9.0 µM 2,4-D (2,4-dichlorophenoxyacetic acid) under light culture conditions. Shoot regeneration showed the highest efficiency on MS medium supplemented with 8.9 µM 6-BA (6-benzylaminopurine) + 5.4 µM NAA (α-naphthaleneacetic acid), while the best rooting medium was MS medium containing 2.7 µM NAA. After transplanting, the transplanted regenerated seedlings showed the highest survival rate (96%) on a substrate mixture with a 2:1:1 ratio of peat/perlite/vermiculite. A protocol and flowchart for the rapid in vitro micropropagation of night lily plants is proposed that will facilitate various genetic, genomic and breeding studies on this crop.

Machine learning-mediated Passiflora caerulea callogenesis optimization.

Callogenesis is one of the most powerful biotechnological approaches for in vitro secondary metabolite production and indirect organogenesis in Passiflora caerulea. Comprehensive knowledge of callogenesis and optimized protocol can be obtained by the application of a combination of machine learning (ML) and optimization algorithms. In the present investigation, the callogenesis responses (i.e., callogenesis rate and callus fresh weight) of P. caerulea were predicted based on different types and concentrations of plant growth regulators (PGRs) (i.e., 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BAP), 1-naphthaleneacetic acid (NAA), and indole-3-Butyric Acid (IBA)) as well as explant types (i.e., leaf, node, and internode) using multilayer perceptron (MLP). Moreover, the developed models were integrated into the genetic algorithm (GA) to optimize the concentration of PGRs and explant types for maximizing callogenesis responses. Furthermore, sensitivity analysis was conducted to assess the importance of each input variable on the callogenesis responses. The results showed that MLP had high predictive accuracy (R2 > 0.81) in both training and testing sets for modeling all studied parameters. Based on the results of the optimization process, the highest callogenesis rate (100%) would be obtained from the leaf explant cultured in the medium supplemented with 0.52 mg/L IBA plus 0.43 mg/L NAA plus 1.4 mg/L 2,4-D plus 0.2 mg/L BAP. The results of the sensitivity analysis showed the explant-dependent impact of the exogenous application of PGRs on callogenesis. Generally, the results showed that a combination of MLP and GA can display a forward-thinking aid to optimize and predict in vitro culture systems and consequentially cope with several challenges faced currently in Passiflora tissue culture.

FEATURES OF IN VITRO CULTIVATION OF ASTRAGALUS DASYANTHUS PALL PLANTS

The research is devoted to the study of the peculiarities of in vitro cultivation of the medicinal plant Astragalus dasyanthus Pall, which is listed in the Red Book of Ukraine and has the status of an endangered species. The cultivation of woolly-flowered astragalus in Ukraine is currently difficult due to the inaccessibility of the raw material base in the temporarily occupied southern part of Ukraine, as well as due to the low seed productivity of the crop. The use of in vitro plant tissue cultivation methods to restore natural communities of A. dasyanthus and expand possible sources of raw materials for the synthesis of medicinal substances is promising. In this work, we investigated the conditions for obtaining aseptic Astragalus dasyanthus plants from seeds and evaluated the effect of preliminary mechanical scarification on its germination energy, taking into account the percentage of sterile seedlings obtained. In addition, the efficiency of microclonal propagation of A. dasyanthus was determined depending on the composition of the culture medium, in particular the concentration of macronutrients and the presence and concentration of growth regulators. It has been shown that aseptic plants of Astragalus dasyanthus can be obtained by surface sterilization of seeds that have been previously subjected to mechanical scarification or by germination on Murashige and Skoog nutrient medium with the addition of 0.1 mg/l benzylaminopurine. It was determined that the type and concentration of cytokinin affects the efficiency of microclonal propagation of A. dasyanthus plants, while halving the content of macronutrients in the nutrient medium does not significantly affect this item. It was found that the addition of benzylaminopurine to the culture medium stimulates the formation of more additional shoots of A. dasyanthus in vitro compared to the culture medium containing kinetin. Thus, Murashige and Skoog medium with the addition of 0.5 mg/l of benzylaminopurine is optimal for in vitro cultivation of woolly-flowered Astragalus plants.

THE INFLUENCE OF GROWTH REGULATORS ON THE SOWING QUALITIES OF EUROPEAN LARCH SEEDS IN THE CONDITIONS OF THE BOTANICAL GARDEN «PODILLYA»

The article highlights the main aspects of the use of growth regulators in the cultivation of European larch seedlings by seed. In the research material of the article, laboratory studies were conducted to determine the effect of different concentrations of growth regulators on the formation of germination and germination energy of European larch seeds. As a result of the research, it was found that the minimum concentration of agrostimulin also increased germination energy by 3.5 % and laboratory germination by 9.6 % compared to the control. It was determined that the use of higher concentrations of agrostimulin concentrations (1 and 2 ml/l) led to an increase in germination energy by 7.8 % and 11.5 %, respectively, and to an increase in germination rate by 14.7 % and 20 %. It was found that the concentration of 2.0 ml/l of emistim-C was the most effective, increasing germination energy by 12.1% compared to the control variant, and laboratory germination reached its maximum value at a concentration of 2 ml/l and exceeded the control by 15.9%. The study revealed that an increase in the concentration of PABA solutions contributes to an increase in germination energy and laboratory germination of European larch seeds. The most pronounced effect is observed at a concentration of 100 mg/l and is 59.6 % and 72.8 %, respectively. The results of the study show that solutions of Triman-1 in concentrations of 25 mg/l and 50 mg/l have a positive effect on germination energy, increasing it by 9% and 9.9% and laboratory germination of European larch seeds by 12.3% and 13.9%, respectively. Also in the course of the research, it was determined that excessive concentrations of different types of growth regulators gave insignificant results compared to the control, which indicates the ineffectiveness of their use.