International Journal of Horticulture 2026, Vol.16, No.3 http://hortherbpublisher.com/index.php/ijh © 2026 HortHerb Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved.
International Journal of Horticulture 2026, Vol.16, No.3 http://hortherbpublisher.com/index.php/ijh © 2026 HortHerb Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved. Publisher HortHerb Publisher Edited by Editorial Team of International Journal of Horticulture Email: edit@ijh.hortherbpublisher.com Website: http://hortherbpublisher.com/index.php/ijh Address: 11388 Stevenston Hwy, PO Box 96016, Richmond, V7A 5J5, British Columbia Canada International Journal of Horticulture (ISSN 1927-5803) is an open access, peer reviewed journal published online by HortHerb Publisher. The journal publishes all the latest and outstanding research articles, letters and reviews in all aspects of horticultural and its relative science, containing horticultural products, protection; agronomic, entomology, plant pathology, plant nutrition, breeding, post harvest physiology, and biotechnology, are also welcomed; as well as including the tropical fruits, vegetables, ornamentals and industrial crops grown in the open and under protection. HortHerb Publisher is an international Open Access publisher specializing in horticulture, herbal sciences, and tea-related research registered at the publishing platform that is operated by Sophia Publishing Group (SPG), founded in British Columbia of Canada. All the articles published in International Journal of Horticulture are Open Access, and are distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. HortHerb Publisher uses CrossCheck service to identify academic plagiarism through the world’s leading plagiarism prevention tool, iParadigms, and to protect the original authors’ copyrights.
International Journal of Horticulture (online), 2026, Vol. 16, No.3 ISSN 1927-5803 http://hortherbpublisher.com/index.php/ijh © 2026 HortHerb Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved. Latest Content Medicinal Coleus (Coleus forskohlii Briq): Different Methods of Propagation-A Review Sanjaai Kumar, Santhos Raj, Jones Ponraj International Journal of Horticulture, 2026, Vol. 16, No. 3, 135-140 The Effect of Stem Recutting and Floral Food on Vase Life of Zinnia elegans Lauren E. Baskin, Coleman L. Etheredge, James DelPrince, Tongyin Li, Myles Landers International Journal of Horticulture, 2026, Vol. 16, No. 3, 141-148 Marker-assisted Selection in Soybean Breeding: Achievements and Limitations Hangming Lin, Xiaoxi Zhou International Journal of Horticulture, 2026, Vol. 16, No. 3, 149-163 Effect of Different Concentrations of Gibberellic Acid (GA3) and NaphthaleneAcetic Acid (NAA) on Growth and Seed Yield of Cabbage at Marpha, Mustang Sharmila Tiwari, Surendra Khadka, Binaya Babu Koirala, Padma Nath Atreya, Arjun Subedi, Sudip Tiwari, Nitika Pandey, Amit Chhetri International Journal of Horticulture, 2026, Vol. 16, No. 3, 164-171 Nutritional and Irrigation Strategies for High-Yield Peach Production Hongpeng Wang, Xingzhu Feng International Journal of Horticulture, 2026, Vol. 16, No. 3, 172-187 Nutrient Management for Enhancing Sweet Cherry Fruit Firmness and Shelf Life Shaomin Yang, Shiying Yu International Journal of Horticulture, 2026, Vol. 16, No. 3, 188-205
International Journal of Horticulture, 2026, Vol.16, No.3, 135-140 http://hortherbpublisher.com/index.php/ijh 135 Review Article Open Access Medicinal Coleus (Coleus forskohlii Briq): Different Methods of Propagation – AReview Sanjaai Kumar 1, Santhos Raj 1, Jones Ponraj 2 1 Department of Horticulture, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu, India 2 Assistant Professor, Department of Horticulture, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu, India Corresponding author: kriswinjones@gmail.com International Journal of Horticulture, 2026, Vol.16, No.3 doi: 10.5376/ijh.2026.16.0012 Received: 13 Jan., 2026 Accepted: 07 Apr., 2026 Published: 20 May, 2026 Copyright © 2026 Sanjaai et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Sanjaai K., Santhosh R., and Jones P., 2026, Medicinal coleus (Coleus forskohlii Briq): different methods of propagation–a review, International Journal of Horticulture, 16(3): 135-140 (doi: 10.5376/ijh.2026.16.0012) Abstract Coleus forskohlii (Briq.), a prominent member of the Lamiaceae family, is a highly valued medicinal herb in Indian Ayurvedic medicine and the global pharmaceutical industry. Its primary therapeutic significance is attributed to forskolin, a unique labdane diterpene concentrated in the root tubers. Forskolin serves as a potent adenylate cyclase activator, making it indispensable for treating ailments such as hypertension, glaucoma, and congestive heart failure. However, the commercial cultivation of C. forskohlii faces significant challenges; conventional propagation via vegetative cuttings is often hindered by slow multiplication rates, seasonal limitations, and susceptibility to soil-borne pathogens. This review provides a comprehensive analysis of various propagation methodologies and biotechnological advancements aimed at enhancing biomass and forskolin yield. It evaluates the impact of plant density, cutting types, and planting methods on root productivity. A significant focus is placed on in vitro techniques, including shoot induction and callus formation using Murashige and Skoog (MS) media supplemented with specific growth regulators like BAP, NAA, and 2,4-D. Furthermore, the review explores the efficacy of brassinosteroids in promoting root development and the application of somatic embryogenesis and direct organogenesis for rapid, large-scale clonal propagation. These biotechnological approaches not only ensure the production of genetically uniform, disease-free planting material but also offer sustainable strategies for the conservation of this endangered medicinal species. By integrating tissue culture with elicitation strategies, the industry can better meet the rising global demand for forskolin while preserving natural germplasm. Keywords Medicinal coleus (Coleus forskohlii Briq); Lamiaceae family; Direct organogenesis; Somatic embryogenesis; Brassinosteroid; Leaf explants; Stem cuttings; Forskolin 1 Introduction Coleus forskohlii belongs to the family Lamiaceae is an important plant in Indian Ayurvedic medicine and herbaceous plant that usually grows at a height of 600–1,500 ft and is spread over the subtropical warm temperate climatic zones of India. It is an ancient and important root drug claimed to improve appetite, increase vitality and useful by curing the ailments like inflammation, flatulence, dropsy etc. (Rupp et al., 1986). It occurs in sub-tropical Himalayan regions from Kumaon to Nepal, Bihar and Deccan plateau of southern India. It is widely cultivated in Rajasthan, Maharashtra, Gujarat, Karnataka, Tamil Nadu and Andhra Pradesh and its present annual production is about 100 tons from the area of 700 ha in India, cultivation of C. forskohlii is picking up in recent years. It is a fast-growing herb and hence more amenable to get exposed to variety of environmental stress. It is Commercially propagated by the means of vegetative cuttings (Reddy et al., 2001). Conventional means of propagation through vegetative cuttings is not suitable to meet the increasing demand of this species due to limited number of propagules produced in each cycle. In vitro propagation is the most efficient and reliable technique for production of ample planting stock of genetic uniformity. Its rapid mode of vegetative propagation makes it a suitable candidate for micro propagation (Biondi and Thorpe, 1982). It is highly valuable as a medicinal plant due to a biologically active compound labdane diterpene present in the root tubers called ‘forskolin’ (Bhat et al., 1977). An active diterpenoid in roots, it poses multiple biological activities such as positive inotropic, anti-hypertensive and antiglaucoma (Seamon and Daly, 1981), which is
International Journal of Horticulture, 2026, Vol.16, No.3, 135-140 http://hortherbpublisher.com/index.php/ijh 136 widely used by pharmaceutical industry due to its wide range of therapeutic effects. The main feature of forskolin is in its roots having unique mechanism of generating cyclic adenosine monophosphate in the cells through direct activation of the catalytic unit of adenylate cyclase enzyme (Yanagihara et al., 1996). For commercial cultivation of this crop optimization of plant population per unit area, method of planting and type of cutting are the prime factors in terms of root yield of medicinal coleus. The most important problem to the commercial growers of coleus is optimum plant density, appropriate type of cutting, method of planting and selecting suitable cultivar. The species is known well for its pharmacological importance. 2 Botanical and Phytochemical Background 2.1 Taxonomical classification The plant belongs to the family Lamiaceae and the order Lamiales. Commonly known as the mint family, it includes a number of potent medicinal plants. It consists of 236 genera and 7,000 species, it is the largest family of the order Lamia.The genus Coleus was first described in 1790, with C. forskohlii classified under the family Lamiaceae, highlighting its botanical significance This classification underscores the plant's historical use in traditional medicine and its potential for further research in phytochemistry. 2.2 Phytochemistry and medicinal relevance A Biologically active compound labdane diterpene present in the root tubers called ‘forskolin’ a key compound extracted from the roots, activates adenylate cyclase, leading to increased levels of cyclic adenosine monophosphate (cAMP) in the cells (Seamon and Daly, 1981). These cAMP plays a key role in various body functions, including heart muscle contraction, smooth muscle relaxation, insulin secretion, and thyroid function and has various physiological effects (Kavitha et al., 2010). The study identifies several minor diterpenoids and other phytochemicals present in C. forskohlii, emphasizing the complexity and potential of its chemical profile. 3 Conventional Propagation Methods 3.1 Rooted cuttings with different planting methods and varieties The yield of medicinal coleus is influenced by plant density, cutting type, and planting methods (Chandrasekhar et al., 2016). Chintapalli local and K-8 varieties were planted using ridge and furrow and flatbed methods, with ridge and furrow methods yielding the highest dry root yield. Genetic factors also significantly impact root yield performance. 3.2 Role of leaves and cutting type in rooting The physiological status of the cutting is vital for successful rooting. Semi-hardwood stem cuttings that retain apical leaves show significantly higher rooting percentages and quality (Belniaki et al., 2018). Studies found that cuttings with leaves produced an average of 16 roots, compared to only 5.7 roots in leafless cuttings, suggesting that endogenous auxins or carbohydrates from the leaves facilitate better establishment. 3.3 Ex situ propagation through stem cuttings The methodology involved selecting disease-free, mature stem cuttings from the mother plant are grown in prepared beds and poly bags in a combination of sand, soil, and manure was used to create optimal growing conditions for the stem cuttings (Patel, 2016). A well-structured water and drainage system is crucial for the successful growth of Coleus forskohlii, preventing water logging and plant damage. Results indicated that the mixed media in poly bags facilitated rapid root and shoot development, supporting the plant's propagation and contributing to its ex-situ conservation efforts. 4 In vitro Regeneration and Micropropagation 4.1 In vitro shoot induction using MS medium Leaf explants were collected and subjected to thorough surface sterilization using running water, antifungal agents, and detergents to ensure aseptic conditions (Murashige and Skoog, 1962). After sterilization, explants were cut into smaller pieces and inoculated in MS media with varying concentrations of hormones 2,4-D (0, 0.01, 0.02,
International Journal of Horticulture, 2026, Vol.16, No.3, 135-140 http://hortherbpublisher.com/index.php/ijh 137 0.03, 0.04, 0.1, 0.5, 0.1, 0.2, 2.5 mg/L), BAP (0.0, 0.01, 0.02, 0.03, 0.04, 0.1, 0.5, 0.1, 1.5 mg/L) in different concentration and combinationto promote callus formation. The pH of the culture media was maintained between 5.4-5.7, adjusted with NaOH or HCl, and solidified with 0.8% agar. Cultures were kept at a controlled temperature of (22±2) °C with a 16-hour photoperiod, with sub culturing performed every two weeks. Callus induction involved sub culturing leaf explants in different concentrations of BAP and NAA to enhance the shoot formation. In regular intervals of two weeks were maintained for monitoring and promoting the number of shoots generated from the callus (Dodds and Roberts, 1982). The study found that MS medium supplemented with BAP and 2,4-D was more effective for callus induction compared to NAA and BAP. Callus exhibited a range of colours (Lisowska and Wysokinska, 2000) and showed significant genetic variability, leading to successful multiple shoot formation from the leaf explants. 4.2 Effective propagation method for salt tolerance Using apical tip as meristem as explant it resulted in quicker plant growth than Nodal Segment This Medicinal coleus explant grown in the Nacl Medium of different Concentration from 0.1% to 0.4%. Later they found that the explant of medicinal coleus was able to withstand and grow at the low concentration of 0.2% of Nacl with the support of BAP and NAA (Sharan et al., 2014). Generally, the use of BAP is considered to be most suitable for promoting large-scale multiplication and micropropagation of various plant species (Shrivastava and Banerjee, 2008). In C. forskohlii, BAP alone has shown best result in promoting multiple shoots formation from the nodal segments and shoot tips (Sen and Sharma, 1991). 4.3 Effect of brastinosteroid in rooting Swamy et al. (2021) found that the application of brassinosteroid significantly increased root numbers in medicinal coleus plants. The application of 28-homobrassinolide at 100 µM resulted in an 85% increase in root numbers by day 15, indicating its effectiveness in promoting rooting. The findings suggest that brassinosteroid could be pivotal in commercial cultivation practices for medicinal plants, enhancing both rooting and vegetative growth (Rao et al., 2010). Terminal cuttings from healthy coleus plants were treated with BRs, monitored for 160 days, and found to increase carbohydrate levels and forskolin content in roots, suggesting a link between growth regulators and secondary metabolite production. 4.4 Effect of cytokinin combined elicitors in coleus In vitro culture techniques using cytokinins combined with elicitors can enhance both the propagation efficiency and secondary metabolite production of Coleus spp., a plant group with notable medicinal value. Cytokinins promote cell division, shoot differentiation, and tissue proliferation, while elicitors stimulate defense-related physiological responses and activate secondary metabolic pathways. Their combined application may therefore improve the accumulation of bioactive compounds associated with antioxidant, anti-inflammatory, and pharmacological activities. Compared with conventional cultivation, tissue culture provides controlled growth conditions, stable nutrient availability, and a shorter production cycle. These factors create a favorable environment for secondary metabolite biosynthesis in Coleus spp. Previous studies have shown that controlled culture conditions and nutrient supply can increase secondary metabolite levels in tissue-cultured plants (Govindaraju et al., 2018). Therefore, optimizing cytokinin types and elicitor combinations is an effective strategy for improving both in vitro propagation and medicinal compound production in coleus. 4.5 Shoot regeneration from proximal, middle and distal segment of Coleus forskohlii leaf explants Rapid shoot regeneration was examined in Three different segments of coleus leaf explant (Proximal, Middle and Distal) where cultured on Murashige and Skoog (MS) Medium with different concentrations of BAP, KIN, NAA, and IAA were tested for shoot elongation. Although callus proliferation was observed, KIN was found to be ineffective in the present study. However, Sharma et al. (1991) previously reported that KIN-enriched media
International Journal of Horticulture, 2026, Vol.16, No.3, 135-140 http://hortherbpublisher.com/index.php/ijh 138 increased the frequency of callus formation from leaf explants. BAP with different concentrations (0.5, 1.0, 2.5, 5.0) in which BAP at 5.0 mg/L yielded the highest shoot regeneration rate is found to be effective for micropropagation of C. forskohlii then Distal leaf segments showed superior regeneration compared to proximal and middle segments, likely due to the presence of more meristematic tissues in the proximal area (Krishna et al., 2010). 4.6 Shoot organogenesis Focuses on the development of callus fromC. forskohlii leaf segments in a sterile environment under controlled conditions. The results show that cytokinin and auxin plays a crucial role in shoot differentiation. Kinetin, when combined with NAA or IAA, leads to the highest shoot regeneration frequency. The study also found that rooting efficiency is highest in half-strength MS medium without growth regulators. The study confirms that in vitro-produced plants maintain clonal purity and forskolin content, making it viable for commercial propagation (Sairam Reddy et al., 2001). 4.7 Large scale clonal propagation Large scale clonal propagation leaf lamina is used as an explant and it is achieved in the media containing 2 μM BA + 0.1 μM NAA Where a highest number of 35 shoots/explant were produced. Later they transferred to root induction medium comprising of IBA, NAA and IAA (1-5 μM) in half-strength MS medium to determine the Most suitable shoot length for proper root induction. The rooted plantlets were acclimatized in field conditions after proper hardening (Sahai and Shahzad, 2010). 4.8 Roots cultivated in shake flask Forskolin production from C. forskohlii roots can be achieved through various cultivation methods, including shake flasks and bioreactors. The transformed hairy root cultures, initiated via Agrobacterium rhizogenes, can produce forskolin in significant quantities, with optimal conditions yielding up to 14 mg/L after 21 days. Hormone-free media and sucrose additions enhance growth and forskolin production, with specific elicitors like methyl jasmonic acid boosting yields. Cutting roots without negatively impacting growth or productivity is a notable advantage in scaling up production (Krombholz et al., 1992). 4.9 Somatic embryogenisis In vitro plant regeneration through somatic embryogenesis in Coleus forskohlii Briq. has been successfully established using leaf explants (Gopi and Mary, 2014). Research indicates that the combination of plant growth regulators (PGRs) significantly influences the regeneration process (Yasmin et al., 2001). Specifically, a medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP) yielded the highest frequency of direct somatic embryogenesis, achieving up to 80% success in embryo maturation and conversion to plantlets. Additionally, alternative methods utilizing direct organogenesis from leaf explants have shown promise, with protocols achieving up to 35 shoots per explant using optimized concentrations of BAP and auxins (Dode et al., 2003). These findings highlight the potential for both somatic embryogenesis and direct organogenesis as effective strategies for the mass propagation and conservation of this medicinally important species, although the reliance on specific PGR combinations may limit broader applicability. 5 Conclusion The comprehensive evaluation of propagation strategies for Coleus forskohlii (Briq.) underscores its standing as a premier medicinal resource, primarily due to the unique pharmacological profile of forskolin. As the global demand for natural adenylate cyclase activators grows, the limitations of traditional vegetative propagation such as low multiplication indices, high susceptibility to soil-borne pathogens, and seasonal dependency have become significant bottlenecks for the pharmaceutical supply chain.
International Journal of Horticulture, 2026, Vol.16, No.3, 135-140 http://hortherbpublisher.com/index.php/ijh 139 This review identifies a critical shift toward biotechnological interventions as the most viable path forward. The synthesis of current research demonstrates that: (1) Micropropagation Efficiency: In vitro protocols, specifically direct organogenesis from leaf lamina and apical meristem culture, offer a robust mechanism for the rapid turnover of disease-free, genetically uniform planting material. The optimization of BAP and NAA concentrations remains the most effective hormone regime for maximizing shoot induction. (2) Regenerative Innovation: Somatic embryogenesis has emerged as a high-efficiency alternative, with maturation rates reaching 80%. This method provides a sophisticated platform for germplasm conservation and large-scale clonal propagation that exceeds the capacity of conventional stem cuttings. (3) Enhanced Phytochemistry: The integration of brassinosteroids and elicitors (such as methyl jasmonic acid) during the culture process not only facilitates superior rooting but also significantly enhances the biosynthetic pathways of secondary metabolites, leading to higher forskolin concentrations. (4) Sustainability and Scaling: Advanced cultivation techniques, including hairy root cultures and shake-flask bioreactors, present a sustainable model for metabolite extraction that bypasses the need for destructive harvesting of wild or field-grown plants. In conclusion, while field-level optimizations like the "ridge and furrow" method provide incremental gains in yield, the future of C. forskohlii lies in the synergy between tissue culture technology and molecular elicitation. Adopting these biotechnological frameworks is essential for ensuring a consistent, high-quality supply of forskolin while simultaneously preserving the genetic diversity and sustainability of this endangered medicinal species. Future research should prioritize the refinement of bioreactor parameters and the exploration of genetic markers to further stabilize forskolin yields in commercial-scale production. Authors’ contributions Sanjaai Kumar and Santhosh Raj conducted the literature review, collected the data regarding various propagation methods, and drafted the manuscript. Jones Ponuraj conceived of the study, participated in its design and coordination, and helped to draft the manuscript. All authors read and approved the final manuscript. Conflict of Interest Disclosure The authors affirm that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest. References Belniaki A.C., Rabel L.A.D.N., Gomes E.N., and Zuffellato-Ribas K.C., 2018, Does the presence of leaves on coleus stem cuttings influence their rooting?, Ornamental Horticulture, 24: 206-210. https://doi.org/10.14295/oh.v24i3.1204 Bhat S.V., Bajqwa B.S., Dornauer H., do Scusa N.D., and Fehlhaber H.W., 1977, Structures and stereochemistry of new labdane diterpiniods fromColeus forskohlii Briq., Tetrahedron Letters, 18(19): 1669-1672. https://doi.org/10.1016/S0040-4039(01)93245-9 Biondi S., and Thorpe T.A., 1982, Clonal propagation of forest tree species, In Proceedings COSTED Symposium on Tissue Culture of Economically Important Plants, Forest Research Institute Malaysia, pp. 197-204. Dodds J.H., and Roberts L.W., 1982, Experiments in plant tissue culture, Cambridge University Press, Cambridge, London, New York. Dode L.B., Bobrowski V.L., Braga E.J.B., Seixas F.K., and Schuch M.W., 2003, In vitro propagation of Ocimum basilicumL. (Lamiaceae), Acta Scientiarum Biological Sciences, 25(2): 435-437. https://doi.org/10.4025/actascibiolsci.v25i2.2034 Gopi C., and Mary M.R., 2014, In vitro plant regeneration through somatic embryogenesis in medicinally important leaf explants of Coleus forskohlii Briq., IOSR Journal of Agriculture and Veterinary Science, 7(9): 20-23. https://doi.org/10.9790/2380-07912023
International Journal of Horticulture, 2026, Vol.16, No.3, 135-140 http://hortherbpublisher.com/index.php/ijh 140 Govindaraju S., and Arulselvi P.I., 2018, Effect of cytokinin combined elicitors (l-phenylalanine, salicylic acid and chitosan) on in vitro propagation, secondary metabolites and molecular characterization of medicinal herb-Coleus aromaticus Benth (L), Journal of the Saudi Society of Agricultural Sciences, 17(4): 435-444. https://doi.org/10.1016/j.jssas.2016.11.001 Krishna G., Sairam Reddy P., Anoop Nair N., Ramteke P.W., and Bhattacharya P., 2010, In vitro direct shoot regeneration from proximal, middle and distal segment of Coleus forskohlii leaf explants, Physiology and Molecular Biology of Plants, 16: 195-200. https://doi.org/10.1007/s12298-010-0021-y Krombholz R., Mersinger R., Kreis W., and Reinhard E., 1992, Production of forskolin by axenic Coleus forskohlii roots cultivated in shake flasks and 20-l glass jar bioreactors, Planta Medica, 58(4): 328-333. https://doi.org/10.1055/s-2006-961478 Lisowska K., and Wysokinska H., 2000, In vitro propagation of Catalpa ovata G. Don, Plant Cell, Tissue and Organ Culture, 60: 171-176. https://doi.org/10.1023/A:1006461520438 Murashige T., and Skoog F., 1962, A revised medium for rapid growth and bio assays with tobacco tissue cultures, Physiologia Plantarum, 15(3). https://doi.org/10.1111/j.1399-3054.1962.tb08052.x Patel D.K., 2016, Vegetative propagation of Coleus forskohlii (Wild) Briq using their stem cutting for ex-situ conservation in herbal garden, Medicinal and Aromatic Plants Research, 5(261): 2167-0412. Rao C.C., Chandrasekhar R., and Rajkumar M., 2016, Studies on the effect of plant density and method of planting on leaf area of medicinal coleus [Coleus forskohlii (Willd) Briq.], Advances in Life Sciences, 5(6): 2204-2206. Rupp R.H., de Souza N.J., and Dohadwalla A.N., 1986, Proceedings of the international symposium on forskolin: its chemical, biological and medicinal potential, Hoechst India Limited, Bombay. Sahai A., and Shahzad A., 2010, In vitro clonal propagation of Coleus forskohlii via direct shoot organogenesis from selected leaf explants, Journal of Plant Biochemistry and Biotechnology, 19: 223-228. https://doi.org/10.1007/BF03263344 Sairam Reddy P., Rodrigues R., and Rajasekharan R., 2001, Shoot organogenesis and mass propagation of Coleus forskohlii from leaf derived callus, Plant Cell, Tissue and Organ Culture, 66: 183-188. https://doi.org/10.1023/A:1010697813852 Seamon K.B., and Daly J.W., 1981, Forskolin: a unique diterpene activator of cyclic AMP-generating systems, Journal of Cyclic Nucleotide Research, 7(4): 201-224. Sen J., Sharma A.K., Sahu N.P., and Mahato S.B., 1992, Production of forskolin in in vitro cultures of Coleus forskohlii, Planta Medica, 58(4): 324-327. https://doi.org/10.1055/s-2006-961477 Sharan A.K., Singh B.P., Dubey S.R., Kumar R., Kishor A., Kumar G., and Kumari S., 2014, Effective propagation and evaluation of salt tolerance in Coleus forskohlii, an endangered herb, International Journal of Advanced Science Engineering Technology, 3(2): 24-31. Sharma N., Chandel K.P.S., and Srivastava V.K., 1991, In vitro propagation of Coleus forskohlii Briq., a threatened medicinal plant, Plant Cell Reports, 10: 67-70. https://doi.org/10.1007/BF00236459 Shrivastava S., and Banerjee M., 2008, In vitro clonal propagation of physic nut (Jatropha curcas L.): influence of additives, International Journal of Integrative Biology, 3(1): 73-77. Swamy K.N., and Rao S.S.R., 2011, Effect of brassinosteroids on the performance of coleus (Coleus forskohlii), Journal of Herbs, Spices and Medicinal Plants, 17(1): 12-20. https://doi.org/10.1080/10496475.2011.556985 Yanagihara H., Sakata R., Minami H., Tanaka H., Shoyama Y., and Murakami H., 1996, Immunoaffinity column chromatography against forskolin using an anti-forskolin monoclonal antibody and its application, Analytica Chimica Acta, 335(1-2): 63-70. https://doi.org/10.1016/S0003-2670(96)00371-6 Yasmin R., Javed F., and Arfan M., 2001, Somatic embryogenesis in callus culture of wheat (Triticum aestivumL.) accession 235/2, International Journal of Agriculture and Biology, 3: 163-166.
International Journal of Horticulture, 2026, Vol.16, No.3, 141-148 http://hortherbpublisher.com/index.php/ijh 141 Research Article Open Access The Effect of Stem Recutting and Floral Food on Vase Life of Zinnia elegans Lauren E. Baskin1, Coleman L. Etheredge 1 , James DelPrince 2, Tongyin Li 1, Myles Landers 3 1 Department of Plant and Soil Sciences, Mississippi State University, 75 B. S. Hood Rd., Mississippi State, MS 39762, USA 2 Mississippi State University Coastal Research and Extension Center, Mississippi State University, 1815 Popp's Ferry Rd., Biloxi, MS 39532, USA 3 College of Business, Mississippi State University, 75 B. S. Hood Rd., Mississippi State, MS 39762, USA Corresponding author: cle248@msstate.edu International Journal of Horticulture, 2026, Vol.16, No.3 doi: 10.5376/ijh.2026.16.0013 Received: 15 Apr., 2026 Accepted: 18 May, 2026 Published: 05 Jun., 2026 Copyright © 2026 Baskin et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Baskin L.E., Etheredge C.L., DelPrince J., Li T.Y., and Landers M., 2026, The effect of stem recutting and floral food on vase life of Zinnia elegans, International Journal of Horticulture, 16(3): 141-148 (doi: 10.5376/ijh.2026.16.0013) Abstract Locally grown specialty cut flowers require species-specific postharvest handling recommendations to maintain flower quality and extend vase life. Knowing the best care for flowers once removed from the mother plant is crucial information for farmers, florists, and the common consumer, as this will affect the longevity of the product and happiness of the consumer. This research examined zinnias variation in vase life between the following test groups: zinnias with untrimmed stems in tap water, zinnias with trimmed stems in tap water, zinnias with untrimmed stems in floral food solution, and zinnias with trimmed stems in floral food solution Across both harvests, recut stems held in floral food had the longest average vase life (16.46 d), followed by non-recut stems in floral food (14.70 d), non-recut stems in tap water (12.80 d), and recut stems in tap water (11.70 d). If adding a floral solution to the water is not an option, then the stems should be left untrimmed. Overall, the stems in tap water that were trimmed had the shortest vase life, and the stems in floral food solution that were trimmed lived the longest out of any of the groups. Keywords Floral preservatives; Flower food; Locally grown; Specialty cut flowers; Vase life; Zinnia elegans 1 Introduction The cut flower industry is dynamic and evolving as there have been many shifts in the current times and trends. One trend is the specialty cut flower movement. Specialty-cut flowers are defined as those that are locally produced in small quantities and stored for short time frames; compared to traditional cut flowers, which are produced in mass quantities and shipped globally (Darras, 2021). Specialty cut flower farmers can greatly profit from these niche plants, as one acre of properly maintained land can generate $25,000 to $30,000 in revenue annually (Byczynski, 2008). An example of a specialty cut flower that can be grown locally is the zinnia, Zinnia elegans. Zinnias show an opposite leaf pattern and range in wide varieties of colors with solid, variegated, and bicolor cultivars (Song et al., 2025). These flowers can exhibit a wide variety of flower structures, ranging from very simple petal arrangements to complex petal florets (Song et al., 2025). Zinnias are disease-resistant, when watered in a manner that prevents water from standing on the leaves (Esringü et al., 2022). They should be cultivated in areas with well-draining, fertile soil that receive a minimum of 8 hours of full sun (Fitzpatrick et al., 2024). A balanced fertilizer may be applied throughout the growing season, should the soil have any nutrient deficiencies, to ensure the plants flourish. Zinnias should be harvested just before full maturity, when blooms are almost fully opened, and placed in cool water with a small amount of floral preservative to ensure a maximum vase life for consumers (Laschkewitsch and Smith, 2000). While many studies have been conducted on the vase life of Zinnia elegans (Carlson et al., 2015; Kalinowski et al., 2022), recent research has shown that the vase life of Zinnia may be negatively affected by a commonly recommended practice, cutting the ends of stems frequently (Kalinowski et al., 2022). These recent findings call into question specifically when zinnia stems should be cut to extend their vase life. The vase life of cut flowers is a critical factor in both the commercial floriculture industry and home floral use, directly influencing customer satisfaction and economic value. Once cut from the mother plant fresh cut flowers have a limited supply of sugars and water stored in their stems and leaves and require supplemental sugars and water supply to maintain flower health and prolong vase life (Pun and Ichimura, 2003). To maintain the longest possible vase life, it is
International Journal of Horticulture, 2026, Vol.16, No.3, 141-148 http://hortherbpublisher.com/index.php/ijh 142 recommended that flower preservatives be added to the water when storing and arranging cut flowers (Nguyen and Lim, 2021). Flower preservatives are specifically formulated for cut flower use and are comprised of three main ingredients; sugars, acidifiers, and biocides (Da Silva, 2003; Nguyen and Lim, 2021). Flower preservatives enhance water absorption by lowering the pH of the solution, suppress microbial development, and supply carbohydrates necessary for the metabolic processes of cut flowers (Han 2003; Nguyen and Lim, 2021). In a study completed by (Iqbal et al., 2012), researchers studied zinnias placed in water with various levels of preservation enhancers, Indole-3-acetic acid (IAA), 1-naphthylacetic acid (NAA), and salicylic acid (SA), it was found that salicylic acid was the most beneficial to the flowers, maintaining the longest average vase life. Additionally, it has been found adding a solute such as aluminum sulfate to the water can enhance water uptake and extend the vase life of zinnias (Kalinowski et al., 2022). Blockage of the xylem vessels can hinder water uptake in cut flowers, this can be caused by various factors such as bacterial proliferation and pinched or damaged stems (Chen et al., 2023). Past research has found that bacterial build up can shorten flower life and cause inferior flower quality (Balestra et al., 2005; Jowkar 2015). Bacterial organisms contribute to the breaking down of cells at the end of flower stems, thus creating an obstruction in a flowers vascular system, slowing water uptake. Stems obstruction may also occur due to injuries to the stem during harvest (Dixon and Peterson, 1989). Wound-induced xylem occlusion is a condition that has been found to affect some species of cut flowers (Manzoor et al., 2024). Wound occlusions have been found to occur as a stress response when a flowers stem is cut (Manzoor et al., 2024). Symptoms of water stress due to stem blockage or damage often present as wilting of the flower petals or bending in the neck of the flower, the area just below the flower structure (Dixon and Peterson, 1989). While various factors can influence the longevity of cut flowers, two commonly recommended practices; recutting stems after harvesting and adding floral food to vase water are widely used to enhance vase life (Nell and Reid, 2001; Ahmad and Dole, 2014; Kalinowski et al., 2022). However, recent research has indicated that recutting zinnia stems once cut from the mother plant can reduce the overall vase life of the flower in certain instances (Kalinowski et al., 2022). These findings leave questions regarding best post-harvest practices for Zinnia elegans. The purpose of this study was to investigate how stem cutting and the application of floral food affect the vase life of Zinnia elegans. Specifically, the study aims to determine whether cutting the ends of the stems enhances flower longevity, whether floral food extends vase life when used with both cut and uncut stems, and to identify which combination of these treatments results in the greatest extension of vase life for Zinnia elegans. By comparing the effects of these common postharvest practices, the study seeks to provide evidence-based recommendations for improving the freshness and ornamental value of Zinnia elegans in vase arrangements. 2 Materials and Methods 2.1 Zinnia propagation protocol The seeds for this study were purchased from Johnny’s Selected Seeds, and the variety was Benary’s Giant Deep Red. The zinnia seeds were initially planted on May 27th, 2025, in 72 cell seed trays, for a total of 864 possible plants. The seeds were then placed in greenhouses located on Mississippi State University campus for 4 weeks to germinate. After the initial 4-week germination period, the seedlings were transplanted into raised beds located in the Thad Cochran research center at Mississippi State University’s on June 25th, 2025. Each seedling was planted approximately 15 cm apart in soil consisting of a mixture of topsoil and humus. There were 400 seedlings planted over 11 beds. Each raised bed was equipped with soaker hoses, allowing the plants to receive adequate water during their growing season. Plants received one application of an all-purpose fertilizer (Expert Gardner 10-10-10, Fort Lauderdale, FL). The fertilizer was evenly spread over the raised bed and worked into the top 5-10 cm of soil. 2.2 Zinnia harvest protocol For this study, zinnia stems were harvested when the outer petals fully expanded and one row of florets opened (Kalinowski et al., 2022). Zinnia stems were cut to a uniform length (45 cm) and placed in tap water to maintain hydration overnight (Kalinowski et al., 2022). The zinnias were left to hydrate in a plastic bucket of tap water at
International Journal of Horticulture, 2026, Vol.16, No.3, 141-148 http://hortherbpublisher.com/index.php/ijh 143 room temperature for one hour before being placed in a floral cooler set at 7 °C for 24 hours to ensure the flowers were properly hydrated before the experiment. The plastic buckets used in this experiment were sanitized with a bleach and water solution prior to the start of the experiment. A total of 200 flowers over two harvests were studied. The first round of 100 flowers was harvested on September 2nd, 2025, and after the 24-hour hydration process, the study began on September 3rd. The second harvest of 100 flowers took place on September 16th, 2025, and the study began on September 17th. There were exactly 2 weeks between the harvest dates. 2.3 Experimental protocol The experiment was conducted as a 2×2×2 factorial design with vase solution, stem recutting treatment, and harvest date as factors. Each of the four treatment groups had 5 replicates (vases), making a total of 20 vases, 5 flowers per vase, per harvest. All vases were made of clear glass, cylindrical in shape, 19 cm high with an 8.5 cm diameter opening. Treatments were replicated across two harvests collected two weeks apart from the same zinnia plants. Flowers were randomized within each treatment group to reduce bias. The following are the four independent groups the zinnias were randomly assigned to: (1) Stems placed in tap water and left untrimmed; (2) Stems placed in tap water and trimmed at an angle; (3) Stems placed in tap water with floral food (Floralife, Flower Food 300) and left untrimmed; (4) Stems placed in tap water with floral food and stems trimmed at an angle. The tap water groups were each filled with 355 mL of water measured out with a measuring cup. The floral food solution groups were filed with 355 mL of the solution. The floral solution was prepared by mixing the powdered floral preservative with tap water at 10 g/L. The floral preservative used in this study was FloraLife original 300 flower food (FloraLife, Kent, Ohio). The room in which the experiment took place had an average air temperature of 21 °C with an average 18.29 μmol/m2/s of light available for 12 h/d at 50% to 60% relative humidity. Vases were placed away from heating, ventilation, and air conditioning systems within the room and remained stationary, not being randomly rotated, during the monitoring and evaluation of the vase life of the zinnias. The water and flower food solution was changed in all vases across all treatments every 3 d, with floral food added back into the vases within floral food treatment groups. A new floral preservative solution was made each time the water was replaced in the vases, the pH of the water was not tested. The zinnias within the treatment groups that received additional stem cuttings had approximately 2.54 cm trimmed off the bottom of their stems every 2 d from the time of harvesting. 2.4 Experiment monitoring and evaluation Flower quality was monitored every 24 hours and evaluated using established protocols in previous studies investigating cut flower vase life longevity (Jones and Hill, 1993; Clark et al., 2010; Aalifar, 2020). Stems were discarded when 50% of the flower was wilted, petals dropped or had turned brown/discolored and/or neck bending/drooping, drying or general stem decline, and/or mold growth of any kind was observed on the flower (Jones and Hill, 1993; Clark et al., 2010; Aalifar, 2020; Kalinowski et al., 2022). 2.5 Data analysis Data from the survey were entered into IBM SPSS Statistics (version 30; IBM Corp., Armonk, NY, USA) and analyzed using analysis of variance (ANOVA) tests, post hoc Duncan’s multiple range test, and frequency statistics. 3 Results and Analysis 3.1 Vase life findings for first harvest of Zinnia elegans ANOVA tests were used to determine if there were differences in vase life between the treatment groups. Significant differences were found in the minimum, maximum, and average vase life within the first harvest. Post hoc tests were used to determine where these differences occurred. Zinnia stems that did not receive a stem cutting and were placed in tap water and stems that did receive a cutting in tap water showed similarities between the test
International Journal of Horticulture, 2026, Vol.16, No.3, 141-148 http://hortherbpublisher.com/index.php/ijh 144 groups, both had a minimum vase life of 8 d (Table 1). Zinnia stems that did not receive a stem cutting and placed in floral food solution and stems that did receive a cutting in floral food solution also showed similarities between the test groups, as they also shared a similar minimum vase life of 12 d and 11 d, respectively (Table 1). There were differences between tap water and floral food solution test groups, as the vase life varies by 3-4 d between the two groups. The zinnias within the flower food solution groups were found to live longer than zinnias in the tap water groups. Table 1 Vase life of cut Zinnia elegans flowers under four postharvest treatments during the first harvest Dependent variable No cut + tap water Cut + tap water No cut + flower food Cut + flower food df F value Pvalue Minimum days 8a 8a 12b 11b 3 9.790 0.001* Maximum days 21b 15a 20b 22c 3 12.333 0.001* Average days 13.56b 11a 15.24b 16.76c 3 25.395 0.001* Note: *Significant at P ≤ 0.05, Means within a row followed by different lowercase letters are significantly different according to Duncan’s multiple range test at P≤0.05 Regarding the differences in maximum vase life, it was found zinnia stems that did receive a stem cutting and placed in tap water had a maximum vase life of 15 d, while stems that did receive a cutting and placed in floral food solution had a maximum vase life of 22 d (Table 1). Untrimmed stems in tap water and untrimmed stems placed in floral food showed similarities between the groups, having similar maximum vase lives of 21 d and 20 d, respectively (Table 1). When analyzing the average number of days flowers remained alive in each treatment group, it was found zinnia stems that did receive a stem cutting and placed in tap water and stems that did receive a cutting and placed in floral food solution were significantly different from all the other groups and each other. The zinnias that were cut and placed in tap water had an average vase life of 11 d, while the zinnias that were cut and placed in a flower food solution had an average of 16.76 d, a difference of 5.76 d. 3.2 Vase life findings for second harvest of Zinnia elegans ANOVA tests were run on the data to determine any differences between the test groups, looking specifically at vase life. Significant differences were found within the second harvest treatment groups based on their maximum, minimum, and average vase life. Post hoc tests examined where these differences occurred. Test results revealed that the uncut stems in tap water and the cut stems in tap water showed similarities, as the two trials shared a minimum vase life of 7 d. The cut stems in tap water and uncut stems in flower food showed statistical similarities in the study. Uncut stems in a floral food solution and cut stems in floral food solution showed similarities, as they had a minimum vase life of 10 d and 9 d, respectively (Table 2). Table 2 Vase life of cut Zinnia elegans flowers under four postharvest treatments during the second harvest Dependent variable No cut + tap water Cut + tap water No cut + flower food Cut + flower food df F value Pvalue Minimum days 7a 7ab 10bc 9c 3 6.202 0.005* Maximum days 19a 19ab 21bc 21c 3 5.920 0.006* Average days 12.04a 12.40a 14.16b 16.16b 3 13.920 0.001* Note: *Significant at P ≤ 0.05, Means within a row followed by different lowercase letters are significantly different according to Duncan’s multiple range test at P≤0.05 ANOVA also indicated differences in the maximum vase life for zinnias in the second harvest based on the treatment groups. Post hoc analysis found the uncut zinnia stems in tap water and cut stems in tap water showed similarities between the test groups. These two trials shared a maximum vase life of 19 d. The cut stems placed in tap water and uncut stems placed in a floral food solution showed similarities in their test groups as well. These two test groups had a difference between the maximum vase life of 2 d. The uncut stems and trimmed stems both placed in the floral food solution showed similarities, as their maximum vase life was both 21 d.
International Journal of Horticulture, 2026, Vol.16, No.3, 141-148 http://hortherbpublisher.com/index.php/ijh 145 When comparing the average vase life between the four treatment groups, ANOVA showed that uncut and cut stems placed in tap water had similarities between the trials within the second harvest test group, as did uncut and cut stems placed in a floral food solution. While there were differences between tap water and floral food trials, the variation between uncut stems versus cut stems placed in tap water had an average vase life difference of 0.36 d. The difference between the floral food solution groups, both uncut and cut stems, was 2 d. However, the two flower food groups both average higher vase life than the tap water groups by 1.76-4.12 d. 3.3 Vase life findings for combined harvest data of Zinnia elegans The data from both harvests was combined and analyzed as a whole to determine if there were differences in the treatment groups based on the collective data for all 200 flowers. ANOVA tests were run on the data to determine any differences in vase life among the test groups. Significant differences were found between the maximum, minimum, and average vase life based on the treatment group the flowers were placed. Post hoc tests used to determine where these differences occurred. ANOVA revealed that the uncut stems and the cut stems across all test subjects placed in tap water showed similarities, as well as uncut stems and the cut stems across all test subjects placed in a floral food solution showed similarities. It is important to note that the differences were between the water type, tap water and floral food, rather than between the factor of if the zinnia stem was trimmed or not. In both tap water groups, the overall minimum day was 7 d, while the floral food solution test group’s minimum days were 10 d for uncut and 9 d for cut stems. This is 2-3 d longer than the minimum for both tap water test groups (Table 3). Table 3 Combined vase life from harvest one and two of cut Zinnia elegans flowers under four postharvest treatments Dependent variable No cut + tap waterI Cut + tap water No cut + flower food Cut + flower food df Fvalue Pvalue Minimum days 7a 7a 10b 9b 3 12.979 0.001* Maximum days 21ab 19a 21b 22c 3 13.046 0.001* Average days 12.8a 11.7a 14.7b 16.46c 3 27.096 0.001* Note: *Significant at P ≤ 0.05; I Average over 2 replications; Means within a row followed by different lowercase letters are significantly different according to Duncan’s multiple range test at P≤0.05 When analyzing the maximum vase life, it was found the uncut stems placed in tap water showed similarities between both cut stems in tap water and uncut stems in floral food solution, however, cut stems in tap water and uncut stems in floral food indicated differences from each other. Both uncut stems in tap water and uncut stems in floral food had a maximum vase life of 21 d. The cut stems and uncut stems in tap water were also found to be similar, having a difference of 2 d in maximum vase life. In this trial, the cut stems in the floral food solution were significantly different from all the other test groups, having the longest vase life of 22 d (Table 3). ANOVA revealed that for average vase life, there were similarities between uncut and cut stems that were placed in tap water. Both the uncut stems and the cut stems that were placed in the floral food solution differed from each other as well as the tap water groups. The average vase life for uncut stems in tap water was 12.8 d and cut stems in tap water was 11.7 d, a difference of 1.1 d. Conversely, the uncut stems in the floral food solution group lived an average of 14.7 d and cut stems in the floral food solution averaged 16.46 d. 3.4 Comparison of vase life between harvest groups ANOVA tests were used to determine if there were any differences in the vase life of the zinnias between the first and second harvest group. No statistically significant differences were found between the maximum, minimum, or average days of vase life between the first and second harvest groups, indicating that vase life between harvests was relatively the same (Table 4).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==