In asymbiotic culture, Goodyera repens germinated and grew well in the presence of 1% glucose and potato extract. Growth on trehalose, a fungal sugar, was comparable with that on glucose. Infected protocorms which grew best on a cellulose carbon source were larger than asymbiotic ones on all media tested.
Asymbiotic protocorms grew slowly and acquired high levels of starch while infected material grew rapidly without accumulating starch. When starch-rich protocorms were infected, their starch became depleted while their growth rate increased, indicating that the fungus suppressed starch synthesis by its host.
When green plantlets were fed with 14CO2, infected plantlets showed greater incorporation into insoluble substances than did asymbiotic ones.