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Mycorrhizal fungi/ conservation of Chinese orchids - Coggle Diagram
Mycorrhizal fungi/ conservation of Chinese orchids
Intro - History
China has ~1,200 sp. of orchid
Inc. comm. trade developed for med & horticulture use
Techniques like in-vitro (seed flasking) / cultivation and propagation still not widely applicable
Threatened by collection & habitat loss
G. elata collapse in 1960s drove research for comm. cultivation
Orchids can be myco-heterotopic, achlorophyllous
achlorophyllous wholly dependent on mycorrhizal fungi
Case Study 1 (G. elata and fungi)
resulted in cultivation and propagation of G. elata
G. elata mycorrhizal fungi 'switch' during different growth phases
mechanism not observed in other orchid sp. yet
seeds of G. elata germinated without A. mellea in field observed in 2000
isolation of 12 fungal strains
fungi of 6 other genera stimulation of G. elata germination observed in 1999-2001
1965 - successful cultivation of G. elata - clonal propagation applied as well
the symbiotic relationship of G. elata and A. mellea (fungi) observed in 1911
G. elata as a treatment for several ailments, 2000 years of wild pop. collection led to decline
Isolation - surveying of fungi
problems with isolating fungi -
slow growth after transplant
lack of inflorescence/ bloom in adults
high mortality rate in seedlings
Dendrobium and Cymbidium genera
Dendrobium - medicinal, horticultural interest, epiphytic orchid, population decline due to harvest
Cymbidium - horticultural interest, terrestrial orchid, trade relies on wild populations
necessary to continue comm. propagation, conservation efforts
Approaches
root tissue plating , isolation & production of pure cultures
isolation and culture from singular structures in root cell
molecular assay of these cultures
many fungi still do not grow on artificial media
characteristics of interest when identifying fungi for isolation
improvement in protocorm growth
growth, reproduction of adult
stimulation of seed growth
Protocorm & seedling growth
fungal elicitors - 1996
stim. plant cell production, secondary metabolism production
provide more insight to interspecies mechanisms between orchid and fungi
particularly effective in protocorm and seedling growth stimulation
stimulation of plant hormones
stim. production of disease-resisting chemical compounds
Future
increase in seedling propagation - large scale reintroduction to natural habitats
isolation and identification of symbionts (fungi)
providing fungi symbiont in germination stage - promote transplant survival rate
research on other species
increase in data on orchid-fungi in natural conditions, increase in research on wild populations
use of symbiont application in commercial propagation operations - small, farmer operations as well
relationships, interactions, mechanisms between orchid and fungi present
adaptability of symbiotic relationship - survival of transplant from cultivated to natural conditions
distribution of mycorrhizal fungi in respective habitats
Reference
Liu Hongxia, Luo Y, Liu Hong. 2010. Studies of mycorrhizal fungi of Chinese orchids and their role in orchid conservation in China--a review. Bot Rev. 76:241+.