Abstract: Using isotopic labelling technique (with 32P. 15N. 86Rb), we demonstrated that Gastrodia elata Bl. might draw nutrients from the soil besides their main nutritional source Armillariella mellea (Vahl. ex Fr) Karst. Hence the soil may considered as its second nutritional source.The nutritional components in the soil(fertilizer)are able to enter Gartrodia elata directly or indirectly though the mediation of Armillariella mellea. They may influence the interrelationship between Gastrodia elata and Armillariella mellea, and the growth of the former. Therefore, the study of the influence of fertilization technique on the yield and quality of Gastrodia elata is of signifi- cance.

Key words: source, secondary, nutrients