Occurrence of Coated Vesicles and Alterations in Plasmalemma in Tomato Leaf Cells Infected by Phytophthora infestans Mont. (de Bary) After Treatment with Fosetyl-Al

Treatment of tomato (Lycopersicum esculentum Mill. cv. Bonny Best) leaves with the systemic fungicide Fosetyl-Al (Tris-o-ethyl phosphonate aluminium) induced the formation of haustorial encasements or cell wall deposits in the leaf cells infected by Phytophthora infestans Mont {de Bary). Numerous coated vesicles and extremely invaginated. saclike plasmalemma were found in close spatial association with wall deposits in haustorium infected cells. Wall deposits in non-infected ceils bordering degenerated, infected, cells were also accompanied by the presence of coated vesicles. In leaf tissues without treatment with Fosetyl-Al. no substantial change in the plasmalemma of infeeted cells was observed and coated vesicles were found only in close contact with large, smooth-surfaced vesicles. No coated vesicles were found associated with wall deposits in non-infected, neighbouring cells. The results are discussed in connection with possible functions of both coated vesicles and plasmalemma