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In recent years, proteomics has become a powerful tool in vitro plant tissue culture research. In Miconia , the most diverse flowering plant genus in the Neotropics, these tools together were unexplored. The group is replete with cases of apomixis (asexual seed formation). Some studies indicate that apomixis may have similarities with somatic embryogenesis (SE). However, there is no investigation into whether explants from apomictic species can affect the accumulation of SE-related proteins in vitro morphogenesis processes, such as callogenesis. This study identifies differentially accumulated proteins related to SE in the callogenesis of three Miconia species with different reproductive systems and whether this can affect their embryogenic capacity. For this, we employed the shotgun comparative proteomics approach in a specific phase of callus proliferation of Miconia australis (obligate apomictic), Miconia hyemalis (facultative apomictic), and Miconia sellowiana (sexual). Comparative proteomic analysis revealed that 190 SE-related proteins were differentially accumulated and distributed among the three experimental comparisons. The calluses of apomictic species showed the highest number of up-accumulated proteins associated with SE. Histological examination of the calluses after 45 days of induction revealed the permanence of cells with meristematic characteristics in the apomictic species, however, in M. sellowiana there was greater cellular vacuolization. These results indicate that calluses of Miconia spp. originated from apomictic species may be better able to acquire embryogenic competence in vitro culture. This study is the first to explore and demonstrate the potential advantages of using proteomics to understand the molecular basis of in vitro morphogenesis in apomictic and sexual species of Miconia , highlighting new perspectives for future research in plant tissue culture. [Display omitted] • Proteomics shed light into the mechanisms underlying in vitro morphogenesis in miconia. • Calluses from apomictic miconia up-accumulated proteins related to somatic embryogenesis. • The cu/zn SOD was up-accumulated in the calluses of obligate apomictic M. australis. • Apomictic species showed a higher prevalence of callus cells with meristematic characteristics. [ABSTRACT FROM AUTHOR]

Nothapodytes nimmoniana (J. Graham) Mabb., commonly known as Narkya, holds immense potential as a medicinal plant, exhibiting a wide array of pharmacological activities. This review provides a comprehensive overview of the methods used for extracting bioactive compounds from different plant parts, along with an exploration of their diverse pharmacological activities. The plant's significance stems from its high content of camptothecin (CPT), a potent anti-cancer alkaloid. We delve into the plant's anti-microbial, antioxidant, anti-tumor, anti-helminthic, anti-malarial, and anti-inflammatory properties. Additionally, we highlight the challenges faced by N. nimmoniana (J. Graham) Mabb., due to overexploitation and its endangered status. To address these concerns, the review underscores the importance of sustainable conservation strategies and the implementation of advanced techniques like plant tissue culture and endophyte production for increased CPT production. This holistic analysis not only sheds light on the plant's multifaceted benefits but also underscores the need for responsible utilization and conservation efforts. [ABSTRACT FROM AUTHOR]

In plant tissue culture, differences in endogenous levels of species-specific plant growth regulators (PGRs) may explain differences in regenerative capacity. In the case of polyamines (PAs), their dynamics and distribution may vary between species, genotypes, tissues, and developmental pathways, such as sexual reproduction and apomixis. In this study, for the first time, we aimed to assess the impact of varying endogenous PAs levels in seeds from distinct reproductive modes in Miconia spp. (Melastomataceae), on their in vitro regenerative capacity. We quantified the free PAs endogenous content in seeds of Miconia australis (obligate apomictic), Miconia hyemalis (facultative apomictic), and Miconia sellowiana (sexual) and evaluated their in vitro regenerative potential in WPM culture medium supplemented with a combination of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). The morphogenic responses were characterized by light microscopy and scanning electron microscopy and discussed regarding the endogenous PAs profiles found. Seeds of M. sellowiana presented approximately eight times more putrescine than M. australis, which was associated with a higher percentage of regenerated calluses (76.67%) than M. australis (5.56%). On the other hand, spermine levels were significantly higher in M. australis. Spermine is indicated as an inhibitor of auxin-carrying gene expression, which may have contributed to its lower regenerative capacity under the tested conditions. These findings provide important insights into in vitro morphogenesis mechanisms in Miconia and highlight the significance of endogenous PA levels in plant regeneration. These discoveries can potentially optimize future regeneration protocols in Miconia, a plant group still underexplored in this area. [ABSTRACT FROM AUTHOR]

Azadirachta indica or neem is recognized for its unique properties, both against insects and in improving human health. However, proteomics studies of this plant's response to abiotic stresses have yet to be reported. Application of this technique highly depends on efficient and optimized sample preparation, in deriving highly reproducible proteomics data. The present study highlights the comparison of protein extraction method which effectively recovers proteins from recalcitrant phenolic-rich tissues of neem callus. Four protocols based on TCA-acetone or/and phenol extraction methods were compared. The TCA-acetone complemented with PVPP method was the most effective approach and generated the greatest total protein yields, spot number, good resolution, and spot intensities. Subsequently, the differential proteomics performed revealed that proteins associated with oxidoreduction, energy, transcriptional, stress response, respiration, and cell division were differentially regulated in salinity stress treatment. Meanwhile, the expression of proteins classified in the group of energy, photosynthesis, protein synthesis, oxidoreduction, and post-transcriptional regulation was altered in the JA-stressed callus. The accumulation of AZA was also noticeably reduced in salinity- and JA-treated callus, suggesting these tested stress parameters were not effective in improving AZA production in the neem callus. Overall, this analysis provides valuable information on the application of plant tissue culture as an alternative for sustainable production of major bioactive constituents in A. indica. Together, the proteomics results brought forward a possible fundamental representation of the mechanism associated with salinity and JA tolerance in the neem callus. [ABSTRACT FROM AUTHOR]

AbstractMelatonin was discovered in plants in 1995, and so-called phytomelatonin. Its characteristic qualities as an antioxidant molecule and with amphiphilic nature make it an excellent candidate to use in plant biotechnological techniques. In plant physiology, melatonin has demonstrated with multiple studies great possibilities of application in crop improvement in aspects such as germination, rooting, plant growth, leaf-senescence, floration, fruit-set, parthenocarpy, fruit ripening and cut flower conservation, among others. In this work, we reviewed many studies on the possible role of melatonin to improve the different plant tissue culture goals, among them: the role of melatonin in callus culture induction and its effects in plant biomass production; the possible action of melatonin as an inductor or elicitor of different secondary metabolite generation in in vitro cultures; the interesting possibilities of melatonin as a protective agent (safener) against abiotic stressors present in in vitro cultures; the potential of melatonin in regulating plant organogenesis, modulating shooting/rooting responses; at last, the studies on the relevant role of melatonin in plant material cryopreservation and the improvement of cell transformation using A. tumefaciens have been discussed. [ABSTRACT FROM AUTHOR]

Mass propagation of cassava on several hectares of arable land due to increasing demand for its starch is not feasible due to land availability, pests and disease invasion, and long cultivation period. Plant cell culture technology is a promising solution despite the scarcity of cassava callus culture for starch production applications. Therefore, a systematic mapping study (SMS) was performed to identify the applications of cassava tissue culture and its prospects in starch production and investigate the important parameters for cassava callus culture initiation. The SMS began with formulating research questions (RQs), conducting searches on various databases, collecting and screening related articles, and extracting and mapping the selected articles. A total of 56 of 589 articles in the initial searching phase were chosen to be used as references to answer each RQ. The extracted data indicates that cassava tissue culture was mostly used for micropropagation, while starch production from its tissue culture is still limited. Basal medium and plant growth regulators influence cassava callus culture initiation most. The findings of the SMS offer a better understanding of cassava tissue culture and the prospects of producing cassava starch. [ABSTRACT FROM AUTHOR]

This study examines the effect of ultraviolet-B (UV-B) and ultraviolet-C (UV-C) radiation on contamination rate and shoot proliferation of Tamban pineapple crown explant. The experimental design was nested and completely randomized with a separate control. The first factor was the type of UV light, namely UV-B and UV-C. The second factor was the duration of UV light exposure, namely 10, 20, 30, and 40 min. This study was carried out from March to June 2023 at the Plant Tissue Culture Laboratory, Faculty of Agriculture, Lambung Mangkurat University, South Kalimantan, Indonesia. Observations were made on the contamination percentage, survival percentage, time of first shoot formation, percentage of explants able to regenerate shoots, and number of shoots. The results showed that UV light treatment decreased the contamination rate. Increasing the duration of UV light exposure decreased the contamination rate, delayed the formation of the first shoot, and affected the number of shoots. UV-B light exposure produced a higher number of shoots than UV-C light. These results suggest that UV-B and UV-C radiation have the potential to optimize surface sterilization protocol and promote somaclonal variation. [ABSTRACT FROM AUTHOR]

Plant tissue in vitro culture is increasingly used in agriculture to improve crop production, nutritional quality, and commercial value. In plant virology, the technique is used as sanitation protocol to produce virus‐free plants. Sanitized (S) artichokes show increased vigour compared to their non‐sanitized (NS) counterparts, because viral infections lead to a decline of growth and development.To investigate mechanisms that control the complex traits related to morphology, growth, and yield in S artichokes compared to NS plants, RNAseq analysis and phenotyping by imaging were used. The role of peroxidases (POD) was also investigated to understand their involvement in sanitized plant development.Results showed that virus infection affected regulation of cell cycle, gene expression and signal transduction modulating cellular response to stimulus/stress. Moreover, primary metabolism and photosynthesis were also influenced, contributing to explain the main morphological differences observed between S and NS artichokes. Sanitized artichokes are also characterized by higher POD activity, probably associated with increased plant growth, rather than strengthening of cell walls.Overall, results show that the differences in development of S artichokes may be derived from the in vitro culture stressor, as well as through pathogen elimination, which, in turn, improve qualitative and quantitative artichoke production. [ABSTRACT FROM AUTHOR]

Petiole segments of an economically ornamental plant Oxalis triangularis A.st.-Hil have been used in the present study for rapid, reliable and systematic in vitro propagation. The morphogenic effect of a-Naphthalene acetic acid (NAA) at various concentrations (0.5 - 3.0 mg/L) was studied individually or in combination with 6-benzylaminopurine (BAP). Superior multiplication rates were achieved on Murashige and Skoog (MS) medium supplemented with 0.5 mg/L NAA and 1.0 mg/L BAP. Of the tested combinations, maximum shoot regeneration (100.00 %), mean shoot number (14.60 ± 0.37 shoots per segment), and shoot length (18.11 ± 0.30 mm) were recorded on MS medium supplemented with 0.5 mg/L NAA and 1.0 mg/L BAP after 6 weeks of incubation. Half-strength MS medium augmented with 1.0 mg/L indole-3-butyric acid (IBA) was the optimal medium for in vitro root induction, (24.60 ± 0.37 roots per shoot with 9.10 ± 0.32 mm in length) after 6 weeks of incubation. The regenerated plantlets showed 100 % survival success during acclimatization and exhibited normal growth characteristics and morphology. This optimized protocol is cost-effective and highly efficient for the rapid mass propagation of Oxalis triangularis A.st.-Hil. [ABSTRACT FROM AUTHOR]

Aquatic plants are grown in aquaria for their beauty and to maintain the quality of water. The explants of Lobelia cardinalis L. were obtained from the Aquatic Plant Center Co., Ltd., Thailand. In vitro clonal propagation offers alternative strategy for its rapid clonal multiplication. In this study, multiple and rapid propagations of Lobelia cardinalis L. with tissue culture techniques were aimed. Highly efficient and repeatable in vitro regeneration protocol was established from nodal segments of Lobelia cardinalis L. Various concentrations and combinations of various plant growth regulators (PGRs) were employed to induce multiple shoots, shoot elongation, number of leaves and rooting of shoots to obtain complete plantlets of Lobelia cardinalis L. Among 2 PGRs such as 6-benzylaminopurine (BAP) and a-Naphthalene acetic acid (NAA) tested for multiple shoot induction. Regenerated shoots had a higher number of shoots on MS medium contained cytokinins with auxins. The maximum shoot proliferation (100 %), number of shoots per explant (6.20 ± 0.51 shoots), shoot length (11.67 ± 0.69 mm) and number of leaves per explant (58.10 ± 0.38 leaves per explant) were observed in MS medium supplemented with 1.0 mg/L BAP and 2.0 mg/L NAA. Rooting was achieved within 3 to 4 weeks on all the rooting media, but MS medium augmented with 1.0 mg/L indole-3-butyric acid (IBA) produced the maximum number of strong and healthy roots (11.70 ± 0.27 roots). The regenerated complete plantlets with healthy roots and shoot system were transferred to 3.5 cm diameter black net plastic pots containing rockwool medium and successfully acclimatized with a survival rate of 100 % in the greenhouse and no phenotypic variations were observed among regenerated plants. The success of this protocol offers highly efficient method of the plant multiplication, which would be beneficial for plant tissue culturist, and nursery people where regular supply of plants is a large number required. This protocol can be utilized for commercial scale propagation. [ABSTRACT FROM AUTHOR]

Solanum nigrum (Solanaceae family) is widely consumed as a fruit or local leafy vegetable after boiling; it also serves as a medicinal plant. Although Agrobacterium-mediated genetic transformation has been established in S. nigrum, the transformation period is long. Specifically, induction of roots takes approximately five weeks for tetraploid and hexaploid S. nigrum, and 7 weeks for diploid Solanum americanum. In this study, we developed an improved rooting-induced method that requires only about 1 week and avoids the use of tissue culture. After generating the transgenic shoots, they were directly transplanted into the soil to facilitate root formation. Remarkably, 100% of the transgenic shoots developed roots within 6 days. Our improved method is time-saving (saving more than 1 month) and simpler to operate. The improved rooting-induced step can be applied to induce roots in various plants using tissue culture, exemplified by the carnation (Dianthus caryophyllus L.). Furthermore, we applied the improved method to generate S. americanum plants expressing AcMYB110 from kiwifruit (Actinidia chinensis spp.). This method will contribute to speeding up gene functional analysis and trait improvement in S. nigrum and might have potential in fast plant molecular breeding processes in crops and rapid rooting induction in tissue culture. [ABSTRACT FROM AUTHOR]

Crocanthemum canadense (L.) Britt. (Cistaceae), Rockrose, is a small perennial herb found in Eastern North America sand barrens. It is classified as critically imperiled in Nova Scotia under the Nova Scotia Endangered Species Act. Nova Scotia C. canadense populations continue to decline; recent counts estimate only 5000–5500 plants remain. To better understand C. canadense conservation, we completed ex-situ in vitro germination and propagation trials using seed collected from native Nova Scotia populations at 14 Wing Canadian Forces Base, Greenwood, Nova Scotia. Concurrently, soil was collected from the same locations to analyze belowground endomycorrhizal symbionts, arbuscular mycorrhizal fungi (AMF). Recent research has documented the presence of AMF within C. canadense roots, however, this is the first study to successfully identify AMF species present in-situ using single spore rDNA barcoding. C. canadense successfully germinated in vitro with high germination rates (average 86.6%) for one population (SB000147) maintained at room temperature with a 16-hour photoperiod. Successful vigor continued to be monitored with regular multiplication and transfers. Eight AMF spores were identified, all members of the genus Rhizophagus. Seven spores identified as Rhizophagus clarus and one as Rhizophagus irregularis. R. clarus are commonly found in many semi-arid environments now including sand barrens. This research will aid in the conservation and restoration of this critically imperiled species by further understanding beneficial soil fungi, an understudied component of the declining sand barrens habitat. [ABSTRACT FROM AUTHOR]

Medicinal plants are invaluable sources of bioactive natural products. To further access plant’s biosynthetic and biotechnological potential, plant tissue culture has become a standard practice. Plant biotechnology might offer selected cell lines with higher metabolic production and allow a more controlled environment for plant development and optimized metabolic flux for the biosynthesis of specific compounds. In this work, we established the in vitro growth of Melia azedarach through micropropagation and evaluated its biosynthetic potential. LC-MS-based metabolic profiling investigation was applied to generate information on natural products composition. A set of computational tools including spectral library matching and in silico prediction of molecular structures and chemical classes were employed to annotate M. azedarach’s plantlets chemical space. Our findings indicate salannin- and nimbolinin-type limonoid production and a series of glycosylated flavonoids and lignan-related phenylpropanoids. This is the first time nimbolinin-related limonoids have been produced in vitro, opening a venue for biotechnological applications of such compounds.Key message: We report the chemical evaluation of natural products diversity of micropropagated Melia azedarach using a combination of metabolomics tools. For the first time, nimbolinin-type limonoids were produced in an in vitro system. [ABSTRACT FROM AUTHOR]

[Objective] To compare the effectiveness of 8 brands of powder MS medium, so as to provide a reference basis for selecting medium for plants tissue culture. [Method Using the leaves, petioles, roots of E. purpurea and stem segments of A. roxburghii as explants, the standard MS and the national authorized invention patent medium without explosive compounds were used as controls, the effectiveness of 8 brands of powder MS medium on callus induction, adventitious bud regeneration, and rooting of E. purpurea and A. roxburghii was compared. [Result] The three brands of powder MS medium codes M5, M6 and M8 were more effective in callus induction of E. purpurea, and no significant difference compared with the two controls (CK1 and CK2), whereas the other five brands were significantly worse than the control. The results of the experiment on inducing adventitious bud of E. purpurea showed that five brands medium codes M1, M2, M3, M4, and M7, failed to induce adventitious buds either by using leaves or petioles as explants in E. purpurea, while the M5 medium not only successfully induced but also obtained more adventitious buds than the control. On the other hand, the comparative experiment of A. roxburghii tissue culture showed that all 10 mediums could successfully induce to obtain adventitious buds, and the induction rate of adventitious buds in M4 was higher than the control, reaching 83.5%. The results of inducing adventitious root in E. purpurea showed that only the medium codes M5 and M8 could successfully induce adventitious roots from adventitious buds as well as the two controls, but the number and length of adventitious roots induced by M5 medium were lower than the two controls. In the experiment of inducing lateral bud rooting of A. roxburghii, all 8 brands medium could successfully induce adventitial roots, and the number and length of adventitious roots induced by M2 were significantly higher than the control. [Conclusion] The effects of 8 brands of powder MS medium were significant different in the tissue culture of E. purpurea and A. roxburghii, and except for the medium codes M5, M6, and M8, other brands of powder MS medium are not suitable for tissue culture of E. purpurea. However, except for M4, all 7 other brands of powder MS medium are suitable for A. roxburghi. [ABSTRACT FROM AUTHOR]

Background: Microbial growth during plant tissue culture is a common problem that causes significant losses in the plant micro-propagation system. Most of these endophytic microbes have the ability to propagate through horizontal and vertical transmission. On the one hand, these microbes provide a rich source of several beneficial metabolites. Results: The present study reports on the isolation of fungal species from different in vitro medicinal plants (i.e., Breynia disticha major, Breynia disticha, Duranta plumieri, Thymus vulgaris, Salvia officinalis, Rosmarinus officinalis, and Ocimum basilicum l) cultures. These species were tested for their indole acetic acid (IAA) production capability. The most effective species for IAA production was that isolated from Thymus vulgaris plant (11.16 µg/mL) followed by that isolated from sweet basil plant (8.78 µg/mL). On screening for maximum IAA productivity, medium, "MOS + tryptophan" was chosen that gave 18.02 μg/mL. The macroscopic, microscopic examination and the 18S rRNA sequence analysis indicated that the isolate that given code T4 was identified as Neopestalotiopsis aotearoa (T4). The production of IAA by N. aotearoa was statistically modeled using the Box-Behnken design and optimized for maximum level, reaching 63.13 µg/mL. Also, IAA extract was administered to sweet basil seeds in vitro to determine its effect on plant growth traits. All concentrations of IAA extract boosted germination parameters as compared to controls, and 100 ppm of IAA extract exhibited a significant growth promotion effect for all seed germination measurements. Conclusions: The IAA produced from N. aotearoa (T4) demonstrated an essential role in the enhancement of sweet basil (Ocimum basilicum) growth, suggesting that it can be employed to promote the plant development while lowering the deleterious effect of using synthetic compounds in the environment. [ABSTRACT FROM AUTHOR]

Notwithstanding the fact that melatonin (MT) and titanium nanoparticles (Ti NPs) alone have been widely used recently to modulate cadmium (Cd) stress in plants, there is a gap in the comparative impacts of these materials on lowering Cd toxicity in sage plants. The objective of this study was to determine how foliar application of MT and Ti NPs affected the growth, Cd accumulation, photosynthesis, water content, lipid peroxidation, and essential oil (EO) quality and quantity of sage plants in Cd-contaminated soils. A factorial experiment was conducted using MT at 100 and 200 μM and Ti NPs at 50 and 100 mg L−1 topically, together with Cd toxicity at 10 and 20 mg Cd kg−1 soil. The results showed that Cd toxicity decreased plant growth and enhanced lipid peroxidation. The Cd stress at 20 mg kg−1 soil resulted in increases in Cd root (693%), Cd shoot (429%), electrolyte leakage (EL, 29%), malondialdehyde (MDA, 72%), shoot weight (31%), root weight (27%), chlorophyll (Chl) a + b (26%), relative water content (RWC, 23%), and EO yield (30%). The application of MT and Ti NPs controlled drought stress by reducing MDA and EL, enhancing plant weight, Chl, RWC, and EO production, and minimizing Cd accumulation in plant tissues. The predominant compounds in the EO were α-thujone, 1,8-cineole, β-thujone, camphor, and α-humulene. MT and Ti NPs caused α-thujone to rise, whereas Cd stress caused it to fall. Based on heat map analysis, MDA was the trait that was most sensitive to treatments. In summary, the research emphasizes the possibility of MT and Ti NPs, particularly MT at 200 μM, to mitigate Cd toxicity in sage plants and enhance their biochemical reactions. [ABSTRACT FROM AUTHOR]

Since prehistoric times, medicinal and aromatic plants (MAPs) have been employed for various therapeutic purposes due to their varied array of pharmaceutically relevant bioactive compounds, i.e. secondary metabolites. However, when secondary metabolites are isolated directly from MAPs, there is occasionally very poor yield and limited synthesis of secondary metabolites from particular tissues and certain developmental stages. Moreover, many MAPs species are in danger of extinction, especially those used in pharmaceuticals, as their natural populations are under pressure from overharvesting due to the excess demand for plant‐based herbal remedies. The extensive use of these metabolites in a number of industrial and pharmaceutical industries has prompted a call for more research into increasing the output via optimization of large‐scale production using plant tissue culture techniques. The potential of plant cells as sources of secondary metabolites can be exploited through a combination of product recovery technology research, targeted metabolite production, and in vitro culture establishment. The plant tissue culture approach provides low‐cost, sustainable, continuous, and viable secondary metabolite production that is not affected by geographic or climatic factors. This study covers recent advancements in the induction of medicinally relevant metabolites, as well as the conservation and propagation of plants by advanced tissue culture technologies. [ABSTRACT FROM AUTHOR]

Unable to move on their own, plants have acquired the ability to produce a wide variety of low molecular weight compounds to survive against various stresses. It is estimated that there are as many as one million different kinds. Plants also have the ability to accumulate high levels of proteins. Although plant-based bioproduction has traditionally relied on classical tissue culture methods, the attraction of bioproduction by plants is increasing with the development of omics and bioinformatics and other various technologies, as well as synthetic biology. This review describes the current status and prospects of these plant-based bioproduction from five advanced research topics, (i) de novo production of plant-derived high value terpenoids in engineered yeast, (ii) biotransformation of plant-based materials, (iii) genome editing technology for plant-based bioproduction, (iv) environmental effect of metabolite production in plant factory, and (v) molecular pharming. [ABSTRACT FROM AUTHOR]

Tissue culture techniques were used to produce large amounts of bioactive compounds with medicinal potential, overcoming space and time constraints for cancer prevention. Rice callus suspension cultures (RCSC) and seed extracts prepared from aromatic rice varieties were used to evaluate the cytotoxic impact on human colon and lung cancer cell lines, as well as a normal control cell line, using Taxol as a positive control. RCSC and seed extracts from two Indian aromatic rice varieties were applied at different concentrations to treat the cancer cell lines and normal lung fibroblasts over varying time intervals. Apoptosis was assessed in 1:5 dilutions of the A549 and HT-29 cell lines treated with RCSC for 72 h, using propidium iodide staining and flow cytometry. RCSC showed a more potent cytotoxic effect than seed extracts with minimal effect on the normal cell line, in contrast to Taxol. Confocal microscopy and flow cytometry further confirmed the apoptotic effect of RCSC. Gas chromatography-mass spectrometry-based metabolic profiling identified metabolites involved in cytotoxicity and highlighted altered pathways. RCSC is proposed as an alternative source for the development of novel anticancer drugs with reduced side effects. [ABSTRACT FROM AUTHOR]

Turmeric has attracted a significant amount of interest in recent years due to its strong antimicrobial properties. The tissue culture of turmeric is preferred to obtain disease-free, highest number of plantlets with good uniform chemistry. However, there is a need to increase the speed of the whole process to meet the growing demand for planting materials and to save time and resources. Iron oxide nanoparticles (Fe3O4 NPs) showed positive effects on callus initiation time, proliferation rate, percent root response, shoot length, percent rooting, and number of roots per explant. Highest callus induction, i.e., 80%, was recorded in cultures that were grown in the presence of 15 mg/L of Fe3O4 NPs. Callus initiated earlier in culture tubes that received green synthesized iron nanoparticles in a concentration between 10–15 mg/L. Biofabricated nanoparticles were characterized for their size, physiochemical, and optical properties through UV–Vis spectroscopy, FTIR, XRD, and SEM. Curcuminoids profiling was performed by implementing LC-Ms that revealed increased quantities in plantlets grown in nano-supplemented media when compared to the control. [ABSTRACT FROM AUTHOR]

In this study, we refine in vitro propagation techniques for Camellia sinensis using a machine learning approach to ascertain the influence of different shooting and rooting conditions on key growth metrics. This was achieved by applying random forest (RF), XGBoost, and multilayer perceptron (MLP) models to dissect the complexities of micropropagation and rooting processes. The research unveiled significant disparities in growth metrics under varying media conditions, underscoring the profound impact of media composition on plant development. The meticulous statistical analysis, employing ANOVA, highlighted statistically significant differences in growth metrics, indicating the critical role of media composition in optimizing growth conditions. Methodologically, the study utilized explants from 2–3-year-old tea plants, which underwent sterilization before being introduced to two distinct culture media for their micropropagation and rooting phases. Statistical analyses were conducted to evaluate the differences in growth outcomes between media, while machine learning models were employed to predict the efficacy of micropropagation and rooting based on various growth regulators. This approach allowed for a comprehensive evaluation of the model's performance in simulating plant growth under different conditions, leveraging metrics like R2, RMSE, and MAE. The findings from this study significantly advance the understanding of tea plant micropropagation, highlighting the utility of machine learning models in agricultural optimization. This research contributes to enhancing micropropagation strategies for the tea plant and exemplifies the transformative potential of integrating machine learning into plant science, paving the way for improved agricultural and horticultural practices. This interdisciplinary approach offers a novel perspective on optimizing in vitro propagation processes, contributing substantially to plant tissue culture and biotechnology. [ABSTRACT FROM AUTHOR]

Tissue culture techniques were used to produce large amounts of bioactive compounds with medicinal potential, overcoming space and time constraints for cancer prevention. Rice callus suspension cultures (RCSC) and seed extracts prepared from aromatic rice varieties were used to evaluate the cytotoxic impact on human colon and lung cancer cell lines, as well as a normal control cell line, using Taxol as a positive control. RCSC and seed extracts from two Indian aromatic rice varieties were applied at different concentrations to treat the cancer cell lines and normal lung fibroblasts over varying time intervals. Apoptosis was assessed in 1:5 dilutions of the A549 and HT-29 cell lines treated with RCSC for 72 h, using propidium iodide staining and flow cytometry. RCSC showed a more potent cytotoxic effect than seed extracts with minimal effect on the normal cell line, in contrast to Taxol. Confocal microscopy and flow cytometry further confirmed the apoptotic effect of RCSC. Gas chromatography-mass spectrometry-based metabolic profiling identified metabolites involved in cytotoxicity and highlighted altered pathways. RCSC is proposed as an alternative source for the development of novel anticancer drugs with reduced side effects.

Camptothecin (CPT), an indole alkaloid popular for its anticancer property, is considered the third most promising drug after taxol and famous alkaloids from Vinca for the treatment of cancer in humans. Camptothecin was first identified in Camptotheca acuminata followed by several other plant species and endophytic fungi. Increased harvesting driven by rising global demand is depleting the availability of elite plant genotypes, such as Camptotheca acuminata and Nothapodytes nimmoniana, crucial for producing alkaloids used in treating diseases like cancer. Conservation of these genotypes for the future is imperative. Therefore, research on different plant tissue culture techniques such as cell suspension culture, hairy roots, adventitious root culture, elicitation strategies, and endophytic fungi has been adopted for the production of CPT to meet the increasing demand without affecting the source plant's existence. Currently, another strategy to increase camptothecin yield by genetic manipulation is underway. The present review discusses the plants and endophytes that are employed for camptothecin production and throws light on the plant tissue culture techniques for the regeneration of plants, callus culture, and selection of cell lines for the highest camptothecin production. The review further explains the simple, accurate, and cost-effective extraction and quantification methods. There is enormous potential for the sustainable production of CPT which could be met by culturing of suitable endophytes or plant cell or organ culture in a bioreactor scale production. Also, different gene editing tools provide opportunities for engineering the biosynthetic pathway of CPT, and the overall CPT production can be improved. Key points: • Camptothecin is a naturally occurring alkaloid with potent anticancer properties, primarily known for its ability to inhibit DNA topoisomerase I. • Plants and endophytes offer a potential approach for camptothecin production. • Biotechnology approaches like plant tissue culture techniques enhanced camptothecin production. [ABSTRACT FROM AUTHOR]

This study investigates the influence of cadmium (Cd) stress on the micropropagation of Goji Berry (Lycium barbarum L.) across three distinct genotypes (ERU, NQ1, NQ7), employing an array of machine learning (ML) algorithms, including Multilayer Perceptron (MLP), Support Vector Machines (SVM), Random Forest (RF), Gaussian Process (GP), and Extreme Gradient Boosting (XGBoost). The primary motivation is to elucidate genotype-specific responses to Cd stress, which poses significant challenges to agricultural productivity and food safety due to its toxicity. By analyzing the impacts of varying Cd concentrations on plant growth parameters such as proliferation, shoot and root lengths, and root numbers, we aim to develop predictive models that can optimize plant growth under adverse conditions. The ML models revealed complex relationships between Cd exposure and plant physiological changes, with MLP and RF models showing remarkable prediction accuracy (R2 values up to 0.98). Our findings contribute to understanding plant responses to heavy metal stress and offer practical applications in mitigating such stress in plants, demonstrating the potential of ML approaches in advancing plant tissue culture research and sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

The habitat of the endemic, endangered, and medically important plant, Stachys cretica subsp. kutahyensis belongs to the family Lamiaceae, is threatened by human influence. This study used a shoot tip explant to standardize a simple and proper micropropagation system for relict endemic plant species. Murashige Skoog medium with different concentrations of gibberellic acid and juglone was used for in vitro germination. Seedlings from in vitro germinated plantlets were used as explant sources in tissue culture studies. The highest shoot average per explant (4.60 shoots) and shoot length (2.70 cm) was determined in MS medium with 2.0 mg/L 6-benzyl amino purine with 100% response in all treatments. This study used different rooting mediums: Murashige Skoog and modified Murashige Skoog media. The effects of Murashige Skoog and different concentrations of indole butyric acid, naphthaleneacetic acid, juglone, and modified MS, and different concentrations of juglone were investigated on rooting development. Elongated shoots were successfully rooted in the Mod MS medium with 10–7 M juglone. Rooted plantlets were gradually transferred to the soil by adapted external conditions. The transfer of S. cretica subsp. kutahyensis plants, adapted to the soil and field conditions (Tavşanlı/Nusretler), successfully carried out. This protocol can be used for conservation studies of endemic, endangered, and medicinally important plant species. [ABSTRACT FROM AUTHOR]

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Chlorogenic acid is one of the most prominent bioactive phenolic acids with great pharmacological, cosmetic and nutritional value. The potential of Berula erecta in tissue culture was investigated for the production of chlorogenic acid and its elicitation combined with light of different wavelengths and low temperature. The content of chlorogenic acid in the samples was determined by HPLC-UV, while the content of total phenolic compounds and the antioxidant activity of their ethanol extracts were evaluated spectrophotometrically. The highest fresh and dry biomasses were obtained in plants grown at 23 °C. This is the first study in which chlorogenic acid has been identified and quantified in Berula erecta. The highest chlorogenic acid content was 4.049 mg/g DW. It was determined in a culture grown for 28 days after the beginning of the experiment at 12 °C and under blue light. The latter also contained the highest content of total phenolic compounds, and its extracts showed the highest antioxidant activity. Berula erecta could, potentially, be suitable for the in vitro production of chlorogenic acid, although many other studies should be conducted before implementation on an industrial scale. [ABSTRACT FROM AUTHOR]

Liriope spicata is an important traditional Chinese medicine and is also used as an ornamental groundcover plant. A tissue culture method, such as somatic embryo regeneration, that can generate large numbers of genetically identical plants would help maintain the characteristics of specific varieties. This study aimed to screen and optimize plant growth regulators for all aspects of somatic embryo regeneration in L. spicata. The plant growth regulators 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (6-BA), naphthalene acetic acid (NAA), gibberellic acid (GA3), indole-3-acetic acid (IAA), and kinetin (KT) were screened in tissue culture media. We found that 2 mg/L 2,4-D + 2 mg/L 6-BA + 0.1 mg/L NAA had the best induction efficiency of 30.95%. During the screening of the somatic embryo proliferation media, we found that MS + 1 mg/L 6-BA + 0.1 mg/L NAA + 20 g/L glucose + 7 g/L agar, with a pH of 5.8, had the best proliferation efficiency of 86.67%. For the germination of somatic embryos, we found that MS + 0.1 mg/L 6-BA + 0.2 mg/L NAA + 1 mg/L GA3 had the best effect, with an efficiency of 29.03%. Indole-3-butyric acid (IBA) had a significant effect on the induction of adventitious shoots, with the formula 1/2 MS + 0.1 mg/L IBA resulting in an efficiency of 100%. The establishment of the regeneration pathway for L. spicata somatic embryos not only ensures the industrial production of species but also provides reference for the application of plant growth regulators in plant tissue culture. [ABSTRACT FROM AUTHOR]

Astragalus spp. has been used in herbal medicine to improve kidney endurance, as a heart tonic, a hepatoprotectant, a diabetic treatment, and a remedy for viral infections. Our research seeks to investigate the possible growth-stimulating properties of chitosan nanoparticles in comparison to iso-pentenyl adenosine (IPA), isopentenyladenine (2ip), 1-Naphthalene-acetic acid (NAA), and in-dole-3-butyric acid (IBA) in Astragalus spp. Plant tissue culture is a technique for reproducing whole plants, organs, tissues, or cells in the laboratory under controlled conditions. Phytohormones (natural or synthetic growth regulators) at appropriate phases of development or maturity can then be used to impact plant development. Callus induction methods, as well as shoot and root micropropagation protocols, were established on Astragalus spp. seeds. Ionic gelatination was used to create chitosan nanoparticles in this study. Molecular docking proved that chitosan showed an energy binding of -7.86 kcal/ mol against ERF-1 target site. Chitosan formed seven hydrogen bonds with Glu5, Gln282, Asn9, Lys16, Glu324 and Glu390. The bond lengths were 2.05, 1.95, 2.05, 2.02, 2.01, 1.90, and 1.84 Å. Among the various ratios and mixes of four growth regulators, a mixture of iso-pentenyl adenosine (IPA) and isopentenyladenine (2ip) with concentrations of 0.5 mg/L from each produced the highest Mean number of shoots (MNS) (17.5%) and Mean shoots length (MSL) (12.5 cm) (1.28%). The best mixture was 0.5 IPA plus 0.5 mg/L 2ip, which was tested on five plant samples; MNS achieved a maximum value of 22.5% in two subcultures, second and third, followed by 18.8% in the first subculture, 15.8% in the fourth subculture, and 13.8% in the fifth subculture. Also, MLS improved in all five subcultures, although the highest value was 15 cm with the second subculture and 13.8 cm with the fourth subculture. Auxins such as 1-Naphthalene-acetic acid (NAA) and In-dole-3-butyric acid (IBA) were applied to plant samples, with the maximum rooting reaching 100% and the root length improving to 14.4 cm in comparison to the control, where rooting and root length were 74% and 12.6 cm, respectively. Chitosan nanoparticles had an average particle size of roughly 60 ± 10 nm and a qua-si-spherical shape. Furthermore, the colloidal stability and surface characteristics of the as-prepared nanoparticles were studied using FT-IR and dynamic light scattering techniques. Chitosan NPs were utilized in various concentrations (0.2, 0.5, 1, 2, 3, and 4 mg/L), The best concentration was 0.5 mg/L stimulating rooting with 83.3%, 4.7 root/shoot number, and root length 6.4 cm.Key message: Our research seeks to investigate the possible growth-stimulating properties of chitosan nanoparticles in comparison to iso-pentenyl adenosine (IPA), isopentenyladenine (2ip), 1-Naphthalene-acetic acid (NAA), and in-dole-3-butyric acid (IBA) in Astragalus spp. [ABSTRACT FROM AUTHOR]

Plant tissue culture (PTC) stands as a powerful and sustainable tool that can contribute significantly to addressing the challenges arising from the heavy extraction of plants, habitat destruction, excessive grazing, etc. It offers an alternative and sustainable approach to the traditional methods of plant propagation and conservation. Advancements in PTC have been rapidly evolving, emphasizing the critical need to assess the current state of research in this field. The present article aims to examine the current trends and research progress globally in the field of PTC according to the information found in the Scopus database from 1933 to 2023. This paper conducts a bibliometric analysis of existing literature on PTC to find the main topics, authors, most cited articles, and countries related to it. A global representation of the concepts was developed by an in-depth analysis of 2498 papers from the Scopus database, using a relational directory network visualization technique based on the VOSviewer software. The finding shows that year 2022 was the most productive year and India emerged as the most productive nation in terms of publications related to PTC. A steady rise of 5.44% was seen in the publishing number. Moreover, the United States has the most connections to other countries. An effort to comprehend the origins and progression of PTC throughout the previous ninety years has been made with this research. The outcome of the study will contribute to identifying future research areas of interest and highlight trending topics that will be useful for further investigation. [ABSTRACT FROM AUTHOR]

The present study investigated the effects of several growth regulators on the early growth of banana plants (cv. Grand Naine) at Horticultural Farm, Department of Horticulture and Post-Harvest Technology, Institute of Agriculture, Visva-Bharti, Srinikatan, West Bengal, during 2021-2022. Six different combinations of two growth regulators, viz. GA3 (100, 150 and 200 ppm) and NAA (50 and 100 ppm) were used in combination with a control treatment (no growth regulators) in three replications under a randomized block design. According to the final observation taken at 75 DAP, the maximum plant height (56.33 cm), number of leaves/plant (8.47), and pseudostem diameter (25.72 cm) were observed under T5 (GA3 @ 150 ppm + NAA @ 100 ppm). The greatest sizes with respect to total leaf length (36.71 cm), leaf lamina length (28.06 cm) and breadth were also observed under the same treatment. Thus, the performance of banana plants at an early stage was markedly influenced by the application of different growth regulators, and the combination of GA3 @ 150 ppm and NAA @ 100 ppm was the most effective combination of plant growth regulators for improved growth and development of tissue-cultured banana plants. [ABSTRACT FROM AUTHOR]

Objective: To obtain protocols for clonal micropropagation, crop planning, and in vitro conservation of Rhycholaelia digbyana (Lindley) Schltr. Methodology: The effects of the Kundson C basal medium and benzylaminopurine concentration were evaluated for clonal micropropagation. The treatment with the greatest number of shoots formed per apex was selected for crop planning. Experiments were conducted to determine the effect of basal medium Murashige and Skoog concentration at 2.2 gL-1 and 4.4 gL-1; sorbitol, mannitol, and sucrose at 1, 2, and 3% on slow growth. Results: The best treatment for clonal micropropagation and crop planning was identified as 21.60 gL-1 Knudson C with 8.80 µM benzylaminopurine. This treatment resulted in uniform-sized shoots produced. The multiplication process can yield 10,240 seedlings in 12 months. Slow growth was achieved using Murashige and Skoog basal media at 2.2 gL-1 with 1% mannitol. Implications: More experiments must be conducted to determine the best shoot induction conditions and improve resource efficiency. Conclusions: These findings represent the first report on micropropagation and ex-situ conservation to preserve germplasm for this species as an important resource for the floriculture industry. [ABSTRACT FROM AUTHOR]

This document provides an overview of various research studies on the cultivation and propagation of ornamental plants. The studies focus on different species and explore methods for in vitro propagation, seed germination, and acclimatization of these plants. Factors such as light quality, UV-C irradiation, arbuscular mycorrhiza fungi, and chitosan are investigated for their effects on the plants' characteristics. The findings contribute to the development of new ornamental plants for landscaping and floriculture, highlighting the importance of micropropagation and seed germination techniques for conservation and exploitation. [Extracted from the article]

Curcuma caesia Roxb. is an ethnomedicinally important, essential oil (EO) yielding aromatic plant. A total of twelve accessions of this plant rhizome were collected from six different agro-climatic zones of West Bengal, India and evaluated for their antimicrobial activities against eight disease-causing, multi-drug-resistant pathogenic strains of urinary-tract infection and respiratory-tract infection. The EO and extracts demonstrated antibacterial activity, with the highest inhibition zone of 18.00 ± 0.08 and 17.50 ± 0.14 mm against Klebsiella pneumoniae by accession 06, even where all the broad-spectrum antibiotics failed to respond. In this study, we employed high-performance thin-layer chromatography (HPTLC) to quantify curcumin, the primary secondary metabolite of C. caesia, and the highest 0.228 mg/gm of curcumin resulted from accession 06. Hence, on the basis of all aspects, accession 06 was identified as the elite chemotype among all twelve accessions. The chemical profiling of EO from accession 06 was done using gas chromatography-mass spectroscopy (GC–MS). Conceivably, about 13 medicinally significant compounds were detected. As this plant species is seasonal and has difficulties in conventional breeding due to dormancy, it must be conserved through in vitro tissue culture for a steady supply throughout the year in massive amounts for agricultural demand. A maximum number of 19.28 ± 0.37 shoots has been obtained in MS medium fortified with 6-Benzylaminopurine, Kinetin, and Naphthalene acetic acid. The genetic uniformity of the plants has been studied through Start Codon Targeted Polymorphism. Therefore, this study must help meet the need for essential phytoactive compounds through a simple, validated, and reproducible plant tissue culture protocol throughout the year. [ABSTRACT FROM AUTHOR]

The traditional method of sexual reproduction in Sargassum fusiforme can lead to difficulties in maintaining the stable inheritance of superior traits. However, technology for asexual proliferation of seedlings in seaweed tissue culture is not well-developed. Therefore, we established a tissue culture method to study, the effects of different parts of S. fusiforme, uniconazole (UIZ) concentrations, and culture methods on the regeneration of tissue-derived juveniles of S. fusiforme. The results showed that the optimal culture conditions were solid medium with modified Provassoli's enriched seawater containing 3 mM UIZ for at least 17 days followed by transfer to liquid medium to induce rapid cell proliferation. These optimal conditions resulted in a callus-like/adventitious bud induction rate of 100%, callus-like/adventitious bud number per explant of 27.43 ± 4.57, and relative growth rate of 3.05 ± 0.27. The best plant parts for tissue culture were the filamentous holdfasts followed by the stem tip. In addition, UIZ treatment increased photosynthesis, resulting in soluble sugar and soluble protein contents of 30.47 mg·g-1 and 1.39 mg·g-1 of in the regenerated juveniles. Based on our results, S. fusiforme can be cultured using a tissue culture technique in which UIZ is added to a solid medium, followed by culture in liquid medium for proliferation. Sargassum fusiforme juveniles obtained using this technique can be cultured continuously until the next culture season and grow normally, providing a technical reference for indoor preservation and expansion of algal species. [ABSTRACT FROM AUTHOR]

Medicinal plant tissue cultures are potential sources of bioactive compounds. In this study, we report the chemical characterization of the callus cultures of three medicinal Tilia spp. (Tilia cordata, Tilia vulgaris and Tilia tomentosa), along with the comparison to bracts and flowers of the same species. Our aim was to show that calli of Tilia spp. are good alternatives to the calli of T. americana for the production of polyphenols and are better sources of a subset of polyphenolic metabolites, compared to the original organs. Calli were initiated from young bracts and grown on woody plant medium containing 1 mg L−1 2,4-D and 0.1 mg L−1 BAP. For chemical characterization, a quality-controlled untargeted metabolomics approach and the quantification of several bioactive compounds was performed with the use of LC-ESI-MS/MS. While bracts and flowers contained flavonoid glycosides (astragalin, isoquercitrin) as major polyphenols, calli of all species contained catechins, coumarins (fraxin, esculin and scopoletin) and flavane aglyca. T. tomentosa calli contained 5397 µg g DW−1 catechin, 201 µg g DW−1 esculin, 218 µg g DW−1 taxifolin and 273 µg g DW−1 eriodictyol, while calli from other species contained lower amounts. T. cordata and T. tomentosa flowers were rich in isoquercitrin, containing 8134 and 6385 µg g DW−1, respectively. The currently tested species contained many of the bioactive metabolites described from T. americana. The production of catechin was shown to be comparable to the most efficient tissue cultures reported. Flowers and bracts contained flavonoid glycosides, including tiliroside, resembling bioactive fractions of T. americana. In addition, untargeted metabolomics has shown fingerprint-like differences among species, highlighting possible chemotaxonomic and quality control applications, especially for bracts. [ABSTRACT FROM AUTHOR]

Quality seed is one of the key inputs for increasing potato (Solanum tuberosum L.) productivity; however, its limited availability is widely recognized as a major constraint to potato production. In Uganda, certified seed production meets approximately 1.5% of effective demand implying most farmers use home‐saved seed. This practice encourages the buildup of degenerative seed‐borne diseases which ultimately affect productivity. Consequently, a study was conducted to determine the productivity of different seed potato production starting stock: tissue culture plantlets (TC) and rooted apical cuttings. Fifty plants of two potato varieties, NAROPOT1 and NAROPOT4, and for each starter material were evaluated both in the field and screen house for two seasons at Kachwekano and Karengyere research stations. Data were collected on the number of tubers per plant and tuber weight. Highly significant differences were observed for the type of starter materials and varieties for the number of tubers per plant (p ≤ 0.001) from both the screen house and field environments. More tubers per plant were obtained from TC for both varieties and the highest recorded was (24.5) for NAROPOT4 and (15.5) for NAROPOT1 in the screen house. Tuber weight was higher from rooted apical cuttings for both varieties NAROPOT1 (153.3 g) and NAROPOT4 (167.7 g). The correlation between the number of tubers per plant and weight was highly significant at p ≤ 0.001. Tissue culture raised plants were more productive in terms of tuber, and numbers are more important in seed production than weight and mini‐tuber production can be done by farmers under affordable conditions. Core Ideas: Tissue culture plantlets produced more tubers per plant than rooted apical cuttings.More tuber weight per plant was obtained from rooted apical cuttings compared to in vitro plants.There was differential performance of varieties with the test starter materials.Varietal response with two types of starter materials in the screen house was comparable to that from the field conditions.Given the higher productivity of in vitro from this study, direct planting is recommended to farmers with ability to manage this level of seed in the screen house, field, or both. [ABSTRACT FROM AUTHOR]

Walnuts are considered a functional food and play a significant role worldwide in people's regular diets. The cultivation and trade of walnut rootstocks and saplings are crucial agricultural activities globally and in Türkiye. Rootstocks are used for grafting and propagating different walnut varieties, and they are essential for tree development, fruit yield, product quantity, and most importantly, their ability to adapt to various ecological conditions and resist diseases and pests. Fruit growing and production of fruit rootstocks of deep-rooted plants in horticulture is given high importance in many countries. However, poor rooting and slow-growing sapling prevent establishing high-yield clonal production. Especially walnut sapling propagation is more complicated and timeconsuming than other woody plants. Our research aims to grow high-quality saplings by using biotechnological techniques. This study used modifications to the current in vitro basal medium and evaluated the effects on in vitro rooting and micrografting of walnut species. The optimal medium for shoots induction (2.93±0.90) of the plant was determined as 4 number medium (Murashige and Skoog (MS) nutrient medium with 5.4 µM NAA + 6.9 µM TDZ + 0.6 µM GA3 and solidified with 0.7% agar). In trials to develop sapling, the 10.33 and 6 rooted (2.5cm root length) shoots were obtained from MS nutrient medium with 14.7 and 19.6 µM of IBA and 348.42 µM of FeSO4.7H2O, and two micrografted plants in MS medium with 19.6 µM of IBA and 348.42 µM of FeSO4.7H2O survived. After three months in the growth chamber, six saplings were ready for transfer to the field. Our findings suggested that FeSO4.7H2O and high dose IBA treatment in MS medium is efficient for in vitro rooting and obtaining in vitro micrografted saplings. [ABSTRACT FROM AUTHOR]

Topolin cytokinins have emerged as valuable tools in micropropagation. This study investigates the metabolism of meta-topolin riboside (mTR) in three distinct tree species: Handroanthus guayacan and Tabebuia rosea (Bignoniaceae), and Tectona grandis (Lamiaceae). Employing labeled N15 mTR, we unraveled the complex mechanisms underlying cytokinin homeostasis, identifying N9-glucosylation as the principal deactivation pathway. Our findings demonstrate a capacity in T. rosea and H. guayacan to reposition the hydroxyl group on the cytokinin molecule, a previously unexplored metabolic pathway. Notably, this study reveals remarkable interfamilial and interspecies differences in mTR metabolism, challenging established perspectives on the role of callus tissue in cytokinin storage. These insights not only illuminate the metabolic intricacies of mTR, a cytokinin with interesting applications in plant tissue culture, but also enhances our understanding of cytokinin dynamics in plant systems, thereby enriching the scientific discourse on plant physiology and cytokinin biology. [ABSTRACT FROM AUTHOR]