Fundamental research on reintroduction of an endangered forest plant to the natural forest by the aid of fungi

2006 Fiscal Year Final Research Report Summary

• Project/Area Number: 17580128
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 林学・森林工学
• Research Institution: Kagoshima University
• Principal Investigator: UMATA Hidetaka Kagoshima University, Faculty of Agriculture, Professor, 農学部, 教授 (30041669)
• Project Period (FY): 2005 – 2006
• Keywords: achlorop hyllous orchids / deforestation / Erythrorchis ochobiensis / endangered plants / fungi / Galeola altissima / myco-parasitic plant / re-introduction

Research Abstract

Global deforestation or decline of forests is causing serious damage to forest plants. For example, a considerable number of plant species became extinct or are in the endangered situation. The aim of this investigation is to get fundamental information for conservation of such endangered species. In this study, Erythrorchis ochobiensis (=Galeola altissima, G. ochobiensis) of Orchidaceae was studied as a case for conservation. This orchid is achlorophyllous and is categorized in the critically endangered species in Japan. This orchid associates with wood-rotting basidiomycetes that colonize within the orchid's roots. Because this orchid lost photosynthet c ability, it depends for carbons on mycobionts throughout its life and needs mycobionts for its seed germination, suggesting that the mycobionts must become a useful tool for conservation.
Conservation attempt of E. ochobiensis was performed by transplantation. Firstly, the mycobiont of this orchid was isolated from the orchid's root. Secondary, the mycobiont and the seeds of this orchid were co-cultured in vitro for preparation of protocorms or juvenile orchids. Lastly, these orchids were buried into the soil. The obtained results propose the following items.
(1) Orchids grow only when they were set in soil with the medium on which the mycobiont was growing, indicating that the mycobiont was essential to re-introduction. Success in re-introduction will be obtained surely by that the container where the orchids are growing with mycobionts on a medium is set in soil. (2) Orchids developing roots and stems well are recommendable for re-introduction. (3) Transplanted orchids developed roots and reached logs then associated with the fungi inhabiting logs if those fungi were symbiotic. Field survey of the symbiotic fungi is required before re-introduction. (4) Mycobiont growth is essential for orchid growth. Recommendable seasons for growth and re-introduction are June, August and September, higher temperate and plenty in rainfall seasons.