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

全球森林砍伐或森林减少正在对森林植物造成严重损害。例如，相当数量的植物物种已经灭绝或处于濒危状态。这次调查的目的是为保护这些濒危物种获得基本资料。本研究以兰科植物赤藓属（=Galeola altissima， G. ochobiensis）为研究对象。这种兰花是无叶的，在日本被列为极度濒危物种。这种兰花与寄生在兰花根部的木材腐烂担子菌有关。由于这种兰花失去了光合作用能力，它一生都依赖于真菌体来获取碳，并且它的种子萌发也需要真菌体，这表明真菌体必须成为一种有用的保护工具。采用移植的方法对其进行保存尝试。首先，从兰根中分离出该兰花的真菌菌体。其次，将真菌与该兰花的种子进行体外共培养，制备原球茎或幼兰花。最后，这些兰花被埋在土里。所得结果提出了以下几点。(1)兰科植物只有在真菌菌生长的培养基中才能生长，说明真菌菌对重新引入至关重要。将兰花与真菌菌体一起生长的容器置于土壤中，肯定能成功地重新引种。(2)根、茎发育良好的兰科宜重新引种。(3)移栽兰花生根并到达原木，与栖息在原木上的真菌共生。在重新引入之前，需要对共生真菌进行实地调查。(4)真菌生长对兰花生长至关重要。适宜生长和重新引种的季节是6月、8月和9月，气候温和，雨量充沛。少

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. … More 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. Less