Abstract
The medicinal effects and techniques for cultivating Anoectochilus formosanus are well-documented, but little is known about the mycorrhizal fungi associated with A. formosanus. Rhizoctonia (Thanatephorus) anastomosis group 6 (AG-6) was the most common species isolated from fungal pelotons in native A. formosanus and represented 67 % of the sample. Rhizoctonia (Ceratobasidium) AG-G, P, and R were also isolated and represent the first occurrence in the Orchidaceae. Isolates of AG-6, AG-R, and AG-P in clade I increased seed germination 44–91 % and promoted protocorm growth from phases III to VI compared to asymbiotic treatments and isolates of AG-G in clade II and Tulasnella species in clade III. All isolates in clades I to III formed fungal pelotons in tissue-cultured seedlings of A. formosanus, which exhibited significantly greater growth than nonmycorrhizal seedlings. An analysis of the relative effect of treatment ( {widehat{p}}_i ) showed that the low level of colonization ( {widehat{p}}_i = 0.30hbox{--} 0.47 ) by isolates in clade I resulted in a significant increase in seedling growth compared to isolates in clades II (0.63–0.82) and III (0.63–0.75). There was also a negative correlation (r = −0.8801) with fresh plant weight and fungal colonization. Our results suggest that isolates in clade I may represent an important group associated with native populations of A. formosanus and can vary in their ability to establish a symbiotic association with A. formosanus. The results presented here are potentially useful for advancing research on the medicinal properties, production, and conservation of A. formosanus in diverse ecosystems.Electronic supplementary materialThe online version of this article (doi:10.1007/s00572-014-0616-1) contains supplementary material, which is available to authorized users.
Highlights
The genus Anoectochilus (Orchidaceae), which comprises more than 40 species, is widespread throughout tropical regions
A representative isolate of Rhizoctonia was selected from each sample site by using hyphal anastomosis and nuclear staining criteria (Sneh et al 1991)
Our results suggested that isolates of anastomosis groups (AGs)-G in clade II and Tulasnella species in clade III sampled from A. formosanus in central regions and other green orchids in northern regions did not increase germination of A. formosanus seeds and promote increased plant development (Fig. 5)
Summary
The genus Anoectochilus (Orchidaceae), which comprises more than 40 species, is widespread throughout tropical regions. Several species of this genus are used in Chinese folk medicines, such as Anoectochilus formosanus Hayata and Anoectochilus koshunensis Hayata, which are terrestrial orchids and distributed only in Taiwan and Okinawa (Japan) (Gutiérrez 2010). Pot culture and transplantation of the tissue-cultured plantlets in soil without colonized mycorrhizal fungi have been challenging due to poor plant growth and increased susceptibility to mites (Chang et al 2007) and plant pathogenic fungi Fusarium oxysporum f. We hypothesized that plant survival could be increased by inoculating seeds or tissue-cultured plantlets with mycorrhizal fungi. There is a paucity of knowledge regarding the mycorrhizal associations between native A. formosanus and its associated mycorrhizal fungi
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
