Abstract: A field investigation on the selection behavior of Cuscuta japonica on their hosts showed that among the test plant communities,the number of coiling, the time of haustorium occurring,and the rate of coiling of C.japonica on hosts followed the order of B.papyrifera,W.chinensis,I.cairica,and L.camara; but the length of the elongation of C.japonica growing tips from coiling to haustorium occurring was with the order of L.camara,I.cairica,W.chinensis,and B.papyrifera. Furthermore,the growing tips of C.japonica coiled 3 circles in left direction on all selected hosts in 12 hrs,but grew away after contacting PVC rods within 24 hrs.The host diversity of C.japonic was beneficial to the survival of both C.japonica and its hosts.The selection behavior of C.japonica on their hosts had no correlation with the total N contents of different hosts.It could be postulated that the secondary metabolites of hosts made a contribution to the selection behavior of C.japonica on their hosts.

Key words: Bacteria, Transport, Sorption, Model, Column experiment