Plasmolysis of rusted flax: a fine-structural study of the host–pathogen interface

Abstract

Plasmolysis of rust-infected flax tissue after treatment with sucrose, mannitol, or calcium chloride solutions caused withdrawal of the host plasmalemma from the cell wall and movement of the host protoplast towards the haustorium. The extrahaustorial membrane, however, was not displaced from its position along the haustorial neck or around the haustorial body. In sucrose and mannitol solutions the extrahaustorial matrix was unchanged in volume, which suggests that it is either a more rigid structure than has usually been suggested or an artifact of fixation. After calcium chloride treatment, the matrix was frequently slightly distended and some plasmolysis of the haustorial protoplast was generally observed; this did not occur in the sucrose or mannitol solutions. The possible significance of these findings is briefly discussed.