Register      Login
Australian Journal of Botany Australian Journal of Botany Society
Southern hemisphere botanical ecosystems
RESEARCH ARTICLE (Open Access)

Synthetic seed propagation of the therapeutic-honey plants Leptospermum polygalifolium and L. scoparium (Myrtaceae)

Ian D. Darby A , Aaron Wiegand A , Shahla Hosseini Bai B , Helen M. Wallace B and Stephen J. Trueman https://orcid.org/0000-0002-7105-7130 B *
+ Author Affiliations
- Author Affiliations

A Centre for Bioinnovation, University of the Sunshine Coast, Maroochydore DC, Qld 4558, Australia.

B Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, Nathan, Brisbane, Qld 4111, Australia.

* Correspondence to: s.trueman@griffith.edu.au

Handling Editor: Noushka Reiter

Australian Journal of Botany 70(6) 447-454 https://doi.org/10.1071/BT22025
Submitted: 8 March 2022  Accepted: 11 September 2022   Published: 10 October 2022

© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

Context: Increasing demand for therapeutic honey has driven establishment of Leptospermum nectar plantations. Methods for propagation involving synthetic seeds (artificially encapsulated miniature cuttings) may speed production of Leptospermum polygalifolium Salisb. and L. scoparium J.R.Forst. & G.Forst.

Aims: The study aimed to determine how nutrient strength of the encapsulation solution and the presence of benzyladenine (BA) in the emergence medium affect shoot and root emergence from synthetic seeds of L. polygalifolium and L. scoparium.

Methods: Nodes from in vitro shoots of three L. polygalifolium clones (P1, P6, P11) and two L. scoparium clones (S6, S12) were encapsulated in 3% sodium alginate with half- or full-strength Murashige and Skoog (MS) medium, and the synthetic seeds were placed on full-strength MS emergence medium containing 0 or 2.2 μM BA.

Key results: Full-strength MS in the encapsulation solution was effective for shoot emergence of both species. BA increased the percentage of synthetic seeds with shoot emergence in clone P6 but decreased the percentage in clone S12. BA stimulated shoot emergence through callus in clones P1, P6, S6 and S12, and increased the number of shoots per emergent synthetic seed in clones S6 and S12. Surprisingly, the simple use of full-strength MS medium without hormones was highly effective for adventitious rooting, stimulating root emergence and plantlet formation in 26–57% of L. polygalifolium and 100% of L. scoparium synthetic seeds.

Conclusions: These two Leptospermum species are highly amenable to propagation via synthetic seeds. A simple formulation of hormone-free, full-strength MS medium in the encapsulation solution and emergence medium provides high frequencies of plantlet conversion.

Implications: Synthetic seeds have potential to assist in mass production of Leptospermum plants for nectar plantations to meet demand for therapeutic honey.

Keywords: adventitious rooting, alginate encapsulation, callus, cytokinin, mānuka honey, methylglyoxal, propagation, tissue culture.


References

Battersby PF, Wilmshurst JM, Curran TJ, Perry GLW (2017) Does heating stimulate germination in Leptospermum scoparium (mānuka; Myrtaceae)? New Zealand Journal of Botany 55, 452–465.
Does heating stimulate germination in Leptospermum scoparium (mānuka; Myrtaceae)?Crossref | GoogleScholarGoogle Scholar |

Bhatia S, Bera T (2015) Somatic embryogenesis and organogenesis. In ‘Modern applications of plant biotechnology in pharmaceutical sciences’. (Eds S Bhatia, K Sharma, R Dahiya, T Bera) pp. 209–230. (Academic Press: London, UK)

Cangahuala-Inocente GC, Dal Vesco LL, Steinmacher D, Torres AC, Guerra MP (2007) Improvements in somatic embryogenesis protocol in Feijoa (Acca sellowiana (Berg) Burret): induction, conversion and synthetic seeds. Scientia Horticulturae 111, 228–234.
Improvements in somatic embryogenesis protocol in Feijoa (Acca sellowiana (Berg) Burret): induction, conversion and synthetic seeds.Crossref | GoogleScholarGoogle Scholar |

Cheruvathur MK, Najeeb N, Thomas TD (2013) In vitro propagation and conservation of Indian sarsaparilla, Hemidesmus indicus L. R. Br. through somatic embryogenesis and synthetic seed production. Acta Physiologiae Plantarum 35, 771–779.
In vitro propagation and conservation of Indian sarsaparilla, Hemidesmus indicus L. R. Br. through somatic embryogenesis and synthetic seed production.Crossref | GoogleScholarGoogle Scholar |

Clarke M, Le Feuvre D (2021) Size and scope of the Australian honey bee and pollination industry: a snapshot. AgriFutures Australia No. 20-136, AgriFutures Australia Project No. PRJ-012405. AgriFutures Australia, Wagga Wagga, NSW, Australia.

Cochrane A, Crawford AD, Errington G, Cuneo P, Viler M, Wood JA, Perrins L (2021) Seed and vegetative material collection. In ‘Plant germplasm conservation in Australia: strategies and guidelines for developing, managing and utilising ex situ collections in Australia’. (Eds AJ Martyn Yenson, CA Offord, PF Meagher, TD Auld, D Bush, DJ Coates, LE Commander, LK Guja, SL Norton, RO Makinson, R Stanley, N Walsh, D Wrigley, L Broadhurst) pp. 85–117. (Australian Network for Plant Conservation: Canberra, ACT, Australia)

Cokcetin NN, Pappalardo M, Campbell LT, Brooks P, Carter DA, Blair SE, Harry EJ (2016) The antibacterial activity of Australian Leptospermum honey correlates with methylglyoxal levels. PLoS ONE 11, e0167780
The antibacterial activity of Australian Leptospermum honey correlates with methylglyoxal levels.Crossref | GoogleScholarGoogle Scholar |

Cooper R, Molan P, Krishnamoorthy L, Harding K (2001) Manuka honey used to heal a recalcitrant surgical wound. European Journal of Clinical Microbiology and Infectious Diseases 20, 758–759.
Manuka honey used to heal a recalcitrant surgical wound.Crossref | GoogleScholarGoogle Scholar |

Cunha ACMCM, Paiva HN, Barros NF, Leite HG, Leite FP (2009) Relaçaõ do estado nutricional de minicepas com o enraizamento de miniestacas de eucalipto. Revista Brasileira de Ciência do Solo 33, 591–599.
Relaçaõ do estado nutricional de minicepas com o enraizamento de miniestacas de eucalipto.Crossref | GoogleScholarGoogle Scholar |

Darby ID, Hosseini Bai S, Wallace HM, Trueman SJ (2021a) Adventitious rooting of cuttings from the therapeutic honey plants, Leptospermum polygalifolium and L. scoparium. Rhizosphere 17, 100306
Adventitious rooting of cuttings from the therapeutic honey plants, Leptospermum polygalifolium and L. scoparium.Crossref | GoogleScholarGoogle Scholar |

Darby ID, Hosseini Bai S, Wallace HM, Trueman SJ (2021b) Micropropagation of the therapeutic-honey plants, Leptospermum polygalifolium and L. scoparium (Myrtaceae). Australian Journal of Botany 69, 310–317.
Micropropagation of the therapeutic-honey plants, Leptospermum polygalifolium and L. scoparium (Myrtaceae).Crossref | GoogleScholarGoogle Scholar |

Gantait S, Mitra M (2019) Applications of synthetic seed technology for propagation, storage, and conservation of orchid germplasms. In ‘Synthetic seeds. Germplasm regeneration, preservation and prospects’. (Eds M Faisal, A Alatar) pp. 301–321. (Springer: Cham, Switzerland)

Gantait S, Kundu S, Ali N, Sahu NC (2015) Synthetic seed production of medicinal plants: a review on influence of explants, encapsulation agent and matrix. Acta Physiologiae Plantarum 37, 98
Synthetic seed production of medicinal plants: a review on influence of explants, encapsulation agent and matrix.Crossref | GoogleScholarGoogle Scholar |

George EF (1993) ‘Plant propagation by tissue culture. Part 1. The technology.’ (Exegetics Ltd: Edington, UK)

Grainger MNC, Manley-Harris M, Lane JR, Field RJ (2016) Kinetics of conversion of dihydroxyacetone to methylglyoxal in New Zealand mānuka honey: Part I – Honey systems. Food Chemistry 202, 484–491.
Kinetics of conversion of dihydroxyacetone to methylglyoxal in New Zealand mānuka honey: Part I – Honey systems.Crossref | GoogleScholarGoogle Scholar |

Grunennvaldt RL, Paungfoo-Lonhienne C, Trueman SJ, Gallart M (2022) Effects of organic and inorganic fertilisers and Paraburkholderia sp. SOS3 on growth and drought responses of the therapeutic-honey plant Leptospermum polygalifolium. Rhizosphere 21, 100471
Effects of organic and inorganic fertilisers and Paraburkholderia sp. SOS3 on growth and drought responses of the therapeutic-honey plant Leptospermum polygalifolium.Crossref | GoogleScholarGoogle Scholar |

Hermanns R, Mateescu C, Thrasyvoulou A, Tananaki C, Wagener FADTG, Cremers NAJ (2020) Defining the standards for medical grade honey. Journal of Apicultural Research 59, 125–135.
Defining the standards for medical grade honey.Crossref | GoogleScholarGoogle Scholar |

Hung CD, Dung CD (2015) Production of chrysanthemum synthetic seeds under non-aseptic conditions for direct transfer to commercial greenhouses. Plant Cell, Tissue and Organ Culture (PCTOC) 122, 639–648.
Production of chrysanthemum synthetic seeds under non-aseptic conditions for direct transfer to commercial greenhouses.Crossref | GoogleScholarGoogle Scholar |

Hung CD, Trueman SJ (2010) Nutrient responses differ between node and organogenic cultures of Corymbia torelliana × C. citriodora (Myrtaceae). Australian Journal of Botany 58, 410–419.
Nutrient responses differ between node and organogenic cultures of Corymbia torelliana × C. citriodora (Myrtaceae).Crossref | GoogleScholarGoogle Scholar |

Hung CD, Trueman SJ (2011a) Encapsulation technology for short-term preservation and germplasm distribution of the African mahogany Khaya senegalensis. Plant Cell, Tissue and Organ Culture (PCTOC) 107, 397–405.
Encapsulation technology for short-term preservation and germplasm distribution of the African mahogany Khaya senegalensis.Crossref | GoogleScholarGoogle Scholar |

Hung CD, Trueman SJ (2011b) Topophysic effects differ between node and organogenic cultures of the eucalypt Corymbia torelliana × C. citriodora. Plant Cell, Tissue and Organ Culture (PCTOC) 104, 69–77.
Topophysic effects differ between node and organogenic cultures of the eucalypt Corymbia torelliana × C. citriodora.Crossref | GoogleScholarGoogle Scholar |

Hung CD, Trueman SJ (2012a) Alginate encapsulation of shoot tips and nodal segments for short-term storage and distribution of the eucalypt Corymbia torelliana × C. citriodora. Acta Physiologiae Plantarum 34, 117–128.
Alginate encapsulation of shoot tips and nodal segments for short-term storage and distribution of the eucalypt Corymbia torelliana × C. citriodora.Crossref | GoogleScholarGoogle Scholar |

Hung CD, Trueman SJ (2012b) Preservation of encapsulated shoot tips and nodes of the tropical hardwoods Corymbia torelliana × C. citriodora and Khaya senegalensis. Plant Cell, Tissue and Organ Culture (PCTOC) 109, 341–352.
Preservation of encapsulated shoot tips and nodes of the tropical hardwoods Corymbia torelliana × C. citriodora and Khaya senegalensis.Crossref | GoogleScholarGoogle Scholar |

Hung CD, Trueman SJ (2012c) Cytokinin concentrations for optimal micropropagation of Corymbia torelliana × C. citriodora. Australian Forestry 75, 233–237.
Cytokinin concentrations for optimal micropropagation of Corymbia torelliana × C. citriodora.Crossref | GoogleScholarGoogle Scholar |

Irish J, Blair S, Carter DA (2011) The antibacterial activity of honey derived from Australian flora. PLoS ONE 6, e18229
The antibacterial activity of honey derived from Australian flora.Crossref | GoogleScholarGoogle Scholar |

Kulus D (2019) Application of synthetic seeds in propagation, storage, and preservation of Asteraceae plant species. In ‘Synthetic seeds. Germplasm regeneration, preservation and prospects’. (Eds M Faisal, A Alatar) pp. 155–179. (Springer: Cham, Switzerland)

Lyne AM, Crisp MD (1996) Leptospermum jingera (Myrtaceae – Leptospermoideae): a new species from north-eastern Victoria. Australian Systematic Botany 9, 301–306.
Leptospermum jingera (Myrtaceae – Leptospermoideae): a new species from north-eastern Victoria.Crossref | GoogleScholarGoogle Scholar |

MPI (Ministry for Primary Industries) (2021) ‘New Zealand honey exports.’ (Ministry for Primary Industries: Wellington, New Zealand) Available at https://www.mpi.govt.nz/dmsdocument/42360-New-Zealand-honey-exports [Accessed 26 April 2022]

Murashige T, Skoog F (1962) A revised medium for rapid growth and bio assays with tobacco tissue cultures. Physiologia Plantarum 15, 473–497.
A revised medium for rapid growth and bio assays with tobacco tissue cultures.Crossref | GoogleScholarGoogle Scholar |

Naz R, Anis M, Alatar AA, Ahmad A, Naaz A (2018) Nutrient alginate encapsulation of nodal segments of Althaea officinalis L., for short-term conservation and germplasm exchange. Plant Biosystems 152, 1256–1262.
Nutrient alginate encapsulation of nodal segments of Althaea officinalis L., for short-term conservation and germplasm exchange.Crossref | GoogleScholarGoogle Scholar |

Norton AM, McKenzie LN, Brooks PR, Pappalardo LJ (2015) Quantitation of dihydroxyacetone in Australian Leptospermum nectar via high-performance liquid chromatography. Journal of Agricultural and Food Chemistry 63, 6513–6517.
Quantitation of dihydroxyacetone in Australian Leptospermum nectar via high-performance liquid chromatography.Crossref | GoogleScholarGoogle Scholar |

Oberschelp GPJ, Gonçalves AN (2016) Assessing the effects of basal media on the in vitro propagation and nutritional status of Eucalyptus dunnii Maiden. In Vitro Cellular & Developmental Biology – Plant 52, 28–37.
Assessing the effects of basal media on the in vitro propagation and nutritional status of Eucalyptus dunnii Maiden.Crossref | GoogleScholarGoogle Scholar |

Offord CA, Makinson RO, Guja LK, Auld TD (2021) Options, major considerations and preparation for plant germplasm conservation. In ‘Plant germplasm conservation in Australia: strategies and guidelines for developing, managing and utilising ex situ collections in Australia’. (Eds AJ Martyn Yenson, CA Offord, PF Meagher, TD Auld, D Bush, DJ Coates, LE Commander, LK Guja, SL Norton, RO Makinson, R Stanley, N Walsh, D Wrigley, L Broadhurst) pp. 23–53. (Australian Network for Plant Conservation: Canberra, ACT, Australia)

Pijut PM, Wowste KE, Michler CH (2011) Promotion of adventitious root formation of difficult-to-root hardwood tree species. Horticultural Reviews 38, 213–251.

Rai MK, Jaiswal VS, Jaiswal U (2008) Encapsulation of shoot tips of guava (Psidium guajava L.) for short-term storage and germplasm exchange. Scientia Horticulturae 118, 33–38.
Encapsulation of shoot tips of guava (Psidium guajava L.) for short-term storage and germplasm exchange.Crossref | GoogleScholarGoogle Scholar |

Rihan HZ, Kareem F, El-Mahrouk ME, Fuller MP (2017) Artificial seeds (principle, aspects and applications). Agronomy 7, 71
Artificial seeds (principle, aspects and applications).Crossref | GoogleScholarGoogle Scholar |

Sharma N, Gowthami R, Pandey R (2019) Synthetic seeds: a valuable adjunct for conservation of medicinal plants. In ‘Synthetic seeds. Germplasm regeneration, preservation and prospects’. (Eds M Faisal, A Alatar) pp. 181–186. (Springer: Cham, Switzerland)

Shipton WA, Jackes BR (1986) Clonal propagation of Leptospermum spp. by tissue culture. Plant Cell Reports 5, 5–8.
Clonal propagation of Leptospermum spp. by tissue culture.Crossref | GoogleScholarGoogle Scholar |

Somerville KD, Bunn E, Rollason A, Turner SR (2021) Tissue culture. In ‘Plant germplasm conservation in Australia: strategies and guidelines for developing, managing and utilising ex situ collections in Australia’. (Eds AJ Martyn Yenson, CA Offord, PF Meagher, TD Auld, D Bush, DJ Coates, LE Commander, LK Guja, SL Norton, RO Makinson, R Stanley, N Walsh, D Wrigley, L Broadhurst) pp. 109–128. (Australian Network for Plant Conservation: Canberra, ACT, Australia)

Spiteri M, Rogers KM, Jamin E, Thomas F, Guyader S, Lees M, Rutledge DN (2017) Combination of 1H NMR and chemometrics to discriminate manuka honey from other floral honey types from Oceania. Food Chemistry 217, 766–772.
Combination of 1H NMR and chemometrics to discriminate manuka honey from other floral honey types from Oceania.Crossref | GoogleScholarGoogle Scholar |

Stephens JM, Schlothauer RC, Morris BD, Yang D, Fearnley L, Greenwood DR, Loomes KM (2010) Phenolic compounds and methylglyoxal in some New Zealand manuka and kanuka honeys. Food Chemistry 120, 78–86.
Phenolic compounds and methylglyoxal in some New Zealand manuka and kanuka honeys.Crossref | GoogleScholarGoogle Scholar |

Stuepp CA, Wendling I, Trueman SJ, Koehler HS, Zuffellato-Ribas KC (2017) The use of auxin quantification for understanding clonal tree propagation. Forests 8, 27
The use of auxin quantification for understanding clonal tree propagation.Crossref | GoogleScholarGoogle Scholar |

Trueman SJ, Richardson DM (2007) In vitro propagation of Corymbia torelliana × C. citriodora (Myrtaceae) via cytokinin-free node culture. Australian Journal of Botany 55, 471–481.
In vitro propagation of Corymbia torelliana × C. citriodora (Myrtaceae) via cytokinin-free node culture.Crossref | GoogleScholarGoogle Scholar |

Trueman SJ, Pegg GS, King J (2007) Domestication for conservation of an endangered species: the case of the Wollemi pine. Tree and Forestry Science and Biotechnology 1, 1–10.

Trueman SJ, McMahon TV, Bristow M (2013) Production of cuttings in response to stock plant temperature in the subtropical eucalypts, Corymbia citriodora and Eucalyptus dunnii. New Forests 44, 265–279.
Production of cuttings in response to stock plant temperature in the subtropical eucalypts, Corymbia citriodora and Eucalyptus dunnii.Crossref | GoogleScholarGoogle Scholar |

Trueman SJ, McMahon TV, Grant EL, Walton DA, Wallace HM (2014) Designing food and habitat trees for urban koalas: graft compatibility, survival and height of tall eucalypt species grafted onto shorter rootstocks. Australian Journal of Botany 62, 196–204.
Designing food and habitat trees for urban koalas: graft compatibility, survival and height of tall eucalypt species grafted onto shorter rootstocks.Crossref | GoogleScholarGoogle Scholar |

Trueman SJ, Hung CD, Wendling I (2018) Tissue culture of Corymbia and Eucalyptus. Forests 9, 84
Tissue culture of Corymbia and Eucalyptus.Crossref | GoogleScholarGoogle Scholar |

Watt MP, Thokoane NL, Mycock D, Blakeway F (2000) In vitro storage of Eucalyptus grandis germplasm under minimal growth conditions. Plant Cell, Tissue and Organ Culture (PCTOC) 61, 161–164.
In vitro storage of Eucalyptus grandis germplasm under minimal growth conditions.Crossref | GoogleScholarGoogle Scholar |

Wendling I, Trueman SJ, Xavier A (2014a) Maturation and related aspects in clonal forestry – part I: concepts, regulation and consequences of phase change. New Forests 45, 449–471.
Maturation and related aspects in clonal forestry – part I: concepts, regulation and consequences of phase change.Crossref | GoogleScholarGoogle Scholar |

Wendling I, Trueman SJ, Xavier A (2014b) Maturation and related aspects in clonal forestry – part II: reinvigoration, rejuvenation and juvenility maintenance. New Forests 45, 473–486.
Maturation and related aspects in clonal forestry – part II: reinvigoration, rejuvenation and juvenility maintenance.Crossref | GoogleScholarGoogle Scholar |

Williams SD, Pappalardo L, Bishop J, Brooks PR (2018) Dihydroxyacetone production in the nectar of Australian Leptospermum is species dependent. Journal of Agricultural and Food Chemistry 66, 11133–11140.
Dihydroxyacetone production in the nectar of Australian Leptospermum is species dependent.Crossref | GoogleScholarGoogle Scholar |

Woodward AJ, Bennett IJ, Pusswonge S (2006) The effect of nitrogen source and concentration, medium pH and buffering on in vitro shoot growth and rooting in Eucalyptus marginata. Scientia Horticulturae 110, 208–213.
The effect of nitrogen source and concentration, medium pH and buffering on in vitro shoot growth and rooting in Eucalyptus marginata.Crossref | GoogleScholarGoogle Scholar |