scholarly journals An expanded role for in vitro symbiotic seed germination as a conservation tool: two case studies in North America (Platanthera leucophaea and Epidendrum nocturnum)

Lankesteriana ◽  
2015 ◽  
Vol 7 (1-2) ◽  
Author(s):  
Emily Massey ◽  
Lawrence Zettler
Keyword(s):  
North America ◽  
Seed Germination ◽  
Case Studies ◽  
Mycorrhizal Fungi ◽  
Orchid Species ◽  
Symbiotic Germination ◽  
Symbiotic Seed Germination ◽  
Platanthera Leucophaea

Interest in using mycorrhizal fungi to cultivate orchids from seed in vitro (=symbiotic seed germina- tion) has intensified in recent years and this approach is now an important conservation tool worldwide. In North America, symbiotic germination has been attempted for a growing number of orchid species in peril as a means to acquire seedlings suitable for reintroduction.

scholarly journals Low-specific Symbiotic Germination of Dendrobium Huoshanense in Vitro, an Endangered Epiphytic Orchid Endemic From South China

2021 ◽  
Author(s):  
Yan-Jing Tang ◽  
Jun Dai ◽  
Yang Li ◽  
Dong-Yu Zhou ◽  
Yong-Mei Xing ◽  
...  
Keyword(s):  
Seed Germination ◽  
Mycorrhizal Fungi ◽  
Blue Staining ◽  
Fungal Strains ◽  
Epiphytic Orchid ◽  
Symbiotic Germination ◽  
Orchid Seed ◽  
Dendrobium Huoshanense ◽  
Initial Seed

Abstract Background: Dendrobium huoshanense is an endangered epiphytic orchid and is endemic to Anhui province of China with a narrow distribution. In nature, orchid seed germination depends on specific mycorrhizal fungi and it is generally assumed that there is a high specific symbiotic germination in narrow distribution orchid. To evaluate the mycorrhizal compatibility and germination-promoting activity of mycorrhizal fungi of D. huoshanense in vitro, we isolated and identified cultured mycorrhizal fungi from the roots of D. huoshanense and D. officinale. A total of 20 mycorrhizal fungal strains (D. huoshanense (n = 6), D. officinale (n = 12), D. nobile (n = 1), D. moniliforme (n = 1)) were used to test the germination-promoting activity of D. huoshanense. Results: In symbiotic germination tests, the mycorrhizal fungi displayed different efficiency in stimulating D. huoshanense seed germination, nine strains stimulated seed development to an advanced seedling stage, while the rest promoted only initial seed germination to stage 2 or stage 3, and the most effective in promoting rapid seed germination was strain 12825(seb) isolated from D. moniliforme, besides, the second most effective fungus was strain WX-7(seb) isolated from D. officinale, both of them belong to Sebacina isolated from non-D. huoshanense. In this study, all twenty fungal strains formed pelotons inside seeds of D. huoshanense based on the trypan blue staining results. Conclusions: Despite its narrow specific habitat preference, D. huoshanense was found to be a mycorrhizal generalist during symbiotic seed germination in vitro. The study is the first to demonstrate the different abilities of orchid mycorrhizal fungi to promote seed germination, protocorm formation and seedling development of D. huoshanense in vitro, providing important microbiological resources for its conservation and reintroduction in nature.

scholarly journals Tulasnella calospora (UAMH 9824) retains its effectiveness at facilitating orchid symbiotic germination in vitro after two decades of subculturing

2021 ◽  
Vol 62 (1) ◽  
Author(s):  
Lawrence W. Zettler ◽  
Caleb J. Dvorak
Keyword(s):  
Mycorrhizal Fungi ◽  
Terrestrial Orchid ◽  
Orchid Species ◽  
The North ◽  
Symbiotic Germination ◽  
Germinating Seeds ◽  
Tulasnella Calospora

Abstract Background The technique of symbiotic germination—using mycorrhizal fungi to propagate orchids from seed in vitro—has been used as one method to cultivate orchids in North America and abroad for > 30 years. A long-held assumption is that mycorrhizal fungi used for this purpose lose their effectiveness at germinating seeds over time with repeated subculturing. Results We provide evidence for the lingering efficacy of one particular strain of Tulasnella calospora (266; UAMH 9824) to stimulate seed germination exemplified by the North American terrestrial orchid, Spiranthes cernua, as a case study. This fungus was originally acquired from roots from Spiranthes brevilabris in 1999 and sub-cultured during the two decades since. Seeds inoculated with the fungus in vitro developed to an advanced protocorm stage after 16 days, and leaf elongation was pronounced after 42 days. In a pilot study, seedlings co-cultured with Tulasnella calospora 266 were deflasked after 331 days and later transferred to soil under greenhouse conditions where they eventually initiated anthesis. During the course of two decades, seeds of 39 orchid species, cultivars and hybrids spanning 21 genera, germinated in vitro co-cultured with Tulasnella calospora 266. These orchids included temperate terrestrials and tropical epiphytes alike. Conclusions The sustained effectiveness of this fungus is noteworthy because it argues against the concept of mycorrhizal fungi losing their symbiotic capability through prolonged subculturing. This study serves as an example of why in situ habitat preservation is essential for the conservation of orchids as a source of potentially useful mycorrhizal fungi.

scholarly journals Symbiotic and Asymbiotic Germination of Dendrobium officinale (Orchidaceae) Respond Differently to Exogenous Gibberellins

2020 ◽  
Vol 21 (17) ◽  
pp. 6104 ◽  
Author(s):  
Juan Chen ◽  
Bo Yan ◽  
Yanjing Tang ◽  
Yongmei Xing ◽  
Yang Li ◽  
...  
Keyword(s):  
Seed Germination ◽  
Mycorrhizal Fungi ◽  
Calcium Binding ◽  
Germination Rate ◽  
Dendrobium Officinale ◽  
Fungal Colonization ◽  
Fungal Mycelium ◽  
High Concentration ◽  
Symbiotic Germination ◽  
Asymbiotic Germination

Seeds of almost all orchids depend on mycorrhizal fungi to induce their germination in the wild. The regulation of this symbiotic germination of orchid seeds involves complex crosstalk interactions between mycorrhizal establishment and the germination process. The aim of this study was to investigate the effect of gibberellins (GAs) on the symbiotic germination of Dendrobium officinale seeds and its functioning in the mutualistic interaction between orchid species and their mycobionts. To do this, we used liquid chromatograph-mass spectrometer to quantify endogenous hormones across different development stages between symbiotic and asymbiotic germination of D. officinale, as well as real-time quantitative PCR to investigate gene expression levels during seed germination under the different treatment concentrations of exogenous gibberellic acids (GA3). Our results showed that the level of endogenous GA3 was not significantly different between the asymbiotic and symbiotic germination groups, but the ratio of GA3 and abscisic acids (ABA) was significantly higher during symbiotic germination than asymbiotic germination. Exogenous GA3 treatment showed that a high concentration of GA3 could inhibit fungal colonization in the embryo cell and decrease the seed germination rate, but did not significantly affect asymbiotic germination or the growth of the free-living fungal mycelium. The expression of genes involved in the common symbiotic pathway (e.g., calcium-binding protein and calcium-dependent protein kinase) responded to the changed concentrations of exogenous GA3. Taken together, our results demonstrate that GA3 is probably a key signal molecule for crosstalk between the seed germination pathway and mycorrhiza symbiosis during the orchid seed symbiotic germination.

scholarly journals Establishment of an EfficientIn VitroRegeneration Protocol for Rapid and Mass Propagation ofDendrobium chrysotoxumLindl. Using Seed Culture

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Potshangbam Nongdam ◽  
Leimapokpam Tikendra
Keyword(s):  
Acetic Acid ◽  
Seed Germination ◽  
Germination Percentage ◽  
Naphthalene Acetic Acid ◽  
Mass Propagation ◽  
Asymbiotic Seed Germination ◽  
Orchid Species ◽  
Seed Culture ◽  
Leaf Formation

An efficientin vitroregeneration protocol from seed culture has been established successfully forDendrobium chrysotoxum, an epiphytic orchid having tremendous ornamental and medicinal values. Seed germination response was encouraging in Mitra (M) medium enriched with different combinations of auxins and cytokinins. Medium supplemented with 0.4% activated charcoal (AC), 2 mg/L 6-benzyl amino purine (BAP), and 2 mg/L indole-3-acetic acid (IAA) produced best seed germination percentage in 2 weeks of culture. Incorporation of higher concentration of kinetin (KN) or BAP in combination with low auxin in medium induced pronounced shooting and leaf formation. Reduction in leaf development was evident when cytokinins exist singly in medium indicating synergistic effect of auxin and cytokinin in leaf induction. Presence of elevated level of indole-3-butyric acid (IBA) or 1-naphthalene acetic acid (NAA) with low cytokinin content in medium generated morein vitrorooting, though IBA was found to be more effective in rooting induction as compared to NAA. Thein vitroprotocol for asymbiotic seed germination developed from the present investigation can be used for rapid mass propagation of this highly importantDendrobiumorchid species.

scholarly journals A Review on Asymbiotic Seed Germination in Orchids through Plant Tissue Culture

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Purnima Paramanik ◽  
◽  
Dipak Kar ◽  
Subrata Raha ◽  
◽  
...  
Keyword(s):  
Seed Germination ◽  
Mineral Nutrients ◽  
Symbiotic Association ◽  
Organic Additives ◽  
Asymbiotic Seed Germination ◽  
Orchid Species ◽  
Mycorrhizal Association ◽  
Commercially Important

Orchid seeds are very small, dust like in appearance, fusiform in shape, lacking endosperm and have undifferentiated embryo covered by transparent seed coat. Mycorrhizal association is required for seed germination of naturally growing orchids. In this symbiotic association, orchid species are dependent on mycorrhizal association for supply of mineral nutrients. In in-vitro condition, such demand of minerals may be compensated by external supply of sugar and mineral nutrients that are required for seed germination of orchid. Several orchids are responded by this asymbiotic seed culture and have commercial importance. Therefore, formulation of efficient in-vitro protocol is important for commercially important orchid species as well as endangered orchid species for conservation. This review paper is focused on various aspects of asymbiotic seed germination of orchids and the role of organic additives in successful seed germination.

scholarly journals ASYMBIOTIC GERMINATION OF CYPRIPEDIUM CALCEOLUS VAR. PARVIFLORUM (ORCHIDACEAE) IN VITRO.

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 618d-618
Author(s):  
Chin-Chang Chu ◽  
Kenneth W. Mudge
Keyword(s):  
Seed Germination ◽  
Suspension Culture ◽  
Agar Medium ◽  
Germination Rate ◽  
Coconut Water ◽  
Mature Seed ◽  
Orchid Species ◽  
Cypripedium Calceolus ◽  
Chilling Treatment

Seeds from mature seed pods of Cypripedium calceolus var. parviflorum were germinated on 1/4 MSMO (Sigma) + 100ml/l coconut water + 1% sucrose +/- 8g/l agar (pH 6.0), and with or without prechilling at 5C for 8 weeks. Protocorm with apex (stage 3) was use as an index of germination. Seeds sown on agar medium withou chilling treatment resulted in a 40% germination rate in 120 days but the germination was very uneven. Seeds germinated on agar medium with prechilling developed more synchronously with 92% germination in 60 days (ie. about 120 days after sowing). Suspension culture of seeds without prechilling resulted in 85% germination after 90 days. The synchronization of seed germination in suspension culture was intermediate between that on agar with and without prechilling. Protocorms germinated in suspension culture appeared morphologically identical to those germinated on agar medium. All stage 3 protocorms developed further on the same agar medium in darkness. Both agar and suspension culture in media containing coconut water provided reliable seed germination methods for this orchid species.

scholarly journals In vitro seed germination in Cymbidium elegans Lindl. and Dendrobium densiflorum Lindl. ex Wall. (Orchidaceae)

2010 ◽  
Vol 6 ◽  
pp. 100-102 ◽  
Author(s):  
Shreeti Pradha ◽  
Bijaya Pant
Keyword(s):  
Seed Germination ◽  
Basal Medium ◽  
Naphthalene Acetic Acid ◽  
Genetic Constitution ◽  
Ms Medium ◽  
Orchid Species ◽  
C Elegans ◽  
Protocorm Formation ◽  
Dendrobium Densiflorum

A comparative study of in vitro seed germination of two endangered orchid species, viz. Cymbidium elegans Lindl. and Dendrobium densiflorum Lindl. ex Wall., was carried out on Murashige and Skoog's (MS) medium, supplemented with different concentrations and combination of 6-benzylaminopurine (BAP) and á-Naphthalene acetic acid (NAA). The hormone-free MS medium and MS medium supplemented with various growth hormones were found effective for in vitro seed germination of both species. However, the seeds of these two species showed variation in their germination behavior. Hormone-free MS basal medium was found most effective for seed germination of D. densiflorum; whereas, basal medium supplemented with BAP (1mg/l) was effective for C. elegans. The seeds of D. densiflorum showed quick response in earlier germination, protocorm formation and further development into seedlings in comparison to C. elegans. In C. elegans, germination of immature seeds started after nine weeks of inoculation; whereas in D. densiflorum, the initiation of germination started after five weeks of culture. The variations in seed germination, protocorm formation and seedling differentiation in the two orchid species might be due to the differences in their genetic constitution and the presence of different endogenous growth stimulating substances present in their seeds. The present study has provided useful information for in vitro clonal mass multiplication of these commercially important orchid species. Key-words: growth hormone; in vitro study; orchid.DOI: 10.3126/botor.v6i0.2917 Botanica Orientalis - Journal of Plant Science (2009) 6: 100-102

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