A study of the capacity of soils to induce nodules in Alnus glutinosa (L.) Gaertn. and Myrica gale L., with special reference to the specificity of the endophytes.

One hundred soil samples from sites in North, Centre and West of Spain were examined for their capacity to induce nodules in alder (Alnus glutinosa) and bog myrtle (Myrica gale). Soils from A. glutinosa communities particularly from places where Myrica was absent, were checked for their infectivity towards M. gale. There was a good correlation between the results, since there was not one single sample which could induce nodules in Myrica which did not do the same in alder. The nodules formed on M. gale plants grown in soils collected from alder habitats showed acetylene-reducing activity at a level comparable to that described in the literature, in the case of other Myrica species. Considering together the results now obtained and in previous work, the possibility of cross-inoculation between M. gale and A. glutinosa, is again put forward and it is thus held that no specificity can be assigned, for the time being, to the respective endophytes.