THE SYMBIOSIS OF CYNANCHUM-VINCETOXICUM ( L) PERS, ASCLEPIAS-CURASSAVICA L AND CEROPEGIA-WOODII SCHL (ASCLEPIADACEAE) WITH MYCORRHIZAL FUNGI (VAM)

Subterranean organs of Cynanchum vincetoxicum, Asclepias curassavica a nd Ceropegia woodii (Asclepiadaceae) were studied in respect to their symbiosis with VAM-fungi. Investigations revealed that both, cultivate d plants and those from their natural habitat, were infected by these fungi. The structure of the endophyte, in these plants, is comparable with those in other flowering plants. The hyphae grow mainly in the in tercellular space within the root cortex and also the vesicles are bui ld intercellularly. Only the arbuscles are build intracellularly. Ther efore, in the Gentianales the Asclepiadaceae do not demonstrate the sa me socalled structural incompatability as it was described for the Gen tianaceae and Loganiaceae.