A preliminary report on the symbiotic germination of nine Japanese terrestrial orchids

Abstract

To develop an effective propagation method, a symbiotic culture was attempted in nine species of Japanese terrestrial orchids. Seeds of three species of Goodyera (Goodyera biflora var. macrantha, G. foliosa var. laevis, and G. hachijonesis var. matsumurana), when inoculated non-symbiotically or with fungi from the binucleate Rhizoctonia fungus group among the 20 fungus strains tested germinated with virtually the same TTC activity level as embryos. Those on a symbiotic culture with binucleate Rhizoctonia grew markedly well compared with seeds on a non-symbiotic culture. The low germination rates in six of the species in the TTC test results are attributed to the unsuitability of the test culture conditions. There were numerous effective fungal strains with 5 species other than Cypripedium macranthos var. speciosum, which developed a symbiotic relationShip with only one of the fungal isolates tested. Among the 3 species (Aorchis cyclochila, Dactylorhiza aristata, and Gymnadenia camtschatica) the binucleate Rhizoctonia fungal group would be suitable for symbiotic germination and subsequent growth, whereas the 2 species Amitostigma kinoshitae and Ponerorchis graminifolia var. graminifolia, responded better to R. repens.