In vitro propagation of myco-heterotrophic Gastrodia elata

Gastrodia elata must establish symbiotic associations with different compatible fungi at seed germination and during vegetative growth. One of the major problems associated with its field production is the degeneration of tubers, which is mainly caused by multiple regeneration via vegetative propagation using immature tubers. To overcome this problem, an in vitro asexual propagation method via artificial pollination was developed. Seeds were first germinated on medium containing a leaf-disc from four different Quercus species, previously infected with Mycena osmundicola. Among the four species tested, Q. acutissima was determined to be the best organic resource and the germination rate reached up to 40.4% when a leaf-disc (2 x 2 cm) was provided. Subsequent infection with Armillaria mellea allowed the protocorms to further develop into immature tubers, which can be directly used for field production. In this study, we established an in vitro symbiotic propagation system of G. elata, which might be an efficient way to prevent degeneration of G. elata tubers and the reduction of yield in the field.