Background: Cypripedium subtropicum is a unique, endangered lady's slipper orchid with evergreen leaves on non-dormant shoots that is native to southwestern China. This study documents the major developmental events in C. subtropicum seed development from fertilization to seed maturity, determines the optimum period for seed collection, and examines the cytokinin requirements for asymbiotic germination and protocorm survival.
Results: Structural studies revealed that embryo development proceeded after successful fertilization at 60 days after pollination (DAP). At 105 DAP, a globular embryo with the shrinking inner seed coat was observed, and seeds collected at this time point exhibited optimal germination. After 120 DAP, most seeds had a mature embryo within the capsule, and within the cells of the embryo proper, numerous proteins/lipid bodies were present as the main storage products. In addition, the inner seed coat had compressed into a thin layer that tightly enclosed the embryo, while the outer seed coat had progressively elongated, resulting in a hair-like appearance of the mature seed. Histochemical staining using Nile red and toluidine blue O (TBO) indicated that the lignified inner and outer seed coats may lead to coat-imposed dormancy. Seeds collected at this stage germinated poorly. Analyses of cytokinin preferences and optimal concentrations for germination and protocorm survival showed that both 6-(γ,γ-dimethylallylamino) purine (2iP) and 6-benzylaminopurine (BA) enhanced germination compared with the control, although higher concentrations of BA (4 and 8 μM) suppressed germination. The protocorm survival rate improved with increasing 2iP concentration.
Conclusions: This study provides a reproducible procedure for culturing immature seeds of C. subtropicum based on a defined time schedule of seed development. In addition, the cytokinin 2iP was shown to improve germination and protocorm survival. This study provides a scientific basis for seedling establishment through asymbiotic seed culture for further reintroduction efforts.
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http://dx.doi.org/10.1186/s40529-022-00359-4 | DOI Listing |
Curr Microbiol
January 2025
Faculty of Science, Department of Biology, Ondokuz Mayis University, Samsun, 55139, Türkiye.
Interactions with mycorrhizal fungi are increasingly recognized as crucial ecological factors influencing orchids' distribution and local abundance. While some orchid species interact with multiple fungal partners, others show selectivity in their mycorrhizal associations. Additionally, orchids that share the same habitat often form relationships with different fungal partners, possibly to reduce competition and ensure stable coexistence.
View Article and Find Full Text PDFPlants (Basel)
December 2024
State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
(Orchidaceae) boasts high ornamental value due to its pleasant aroma, foxtail spike, and elegant floral morphology. Inducing to become tetraploid enhances horticultural traits and facilitates fertile intergeneric hybrids through crosses with other market-available tetraploid species. The experimental design involved the application of colchicine at varying concentrations-0.
View Article and Find Full Text PDFPlant Cell Rep
January 2025
Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
Excessive auxin accumulation inhibits protocorm development during germination of Paphiopedilum spicerianum, delaying shoot meristem formation by downregulating boundary genes (CUC1, CUC2, CLV3) and promoting fungal colonization, essential for seedling establishment. Paphiopedilum, possess high horticultural and conservational value. Asymbiotic germination is a common propagation method, but high rates of protocorm developmental arrest hinder seedling establishment.
View Article and Find Full Text PDFBraz J Microbiol
December 2024
Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.
Orchidaceae is one of the largest plant families and stands out for its wide variety of flowers with ornamental and environmental importance. Cattleya is one of the main commercial genera, presenting a great diversity of species and hybrids that attract the attention of collectors, orchid enthusiasts, and consumers. In their natural environment, orchids associate with mycorrhizal fungi, which are responsible for providing carbon and other nutrients during seed germination.
View Article and Find Full Text PDFCommun Integr Biol
December 2024
Central Department of Botany, Tribhuvan University, Kirtipur, Kathmandu, Nepal.
We isolated endophytic strains from the healthy roots, stems, and leaves of to investigate their plant growth-promoting activities in vitro. Subsequently, Indole acetic acid (IAA) was quantified and the gene (responsible for IAA synthesis in fungi) was amplified and sequenced. Finally, a germination assay was performed with seeds of and a plant growth assay with protocorms of to test their plant growth-promoting activities.
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