[Adhesion of algal spores]

The paper describes the adhesion of algal spores to glass surfaces with different degrees of roughness (surface tension, contact angle and adsorption capacity were taken as indices of roughness). It was observed that spores of various species and different types can be devided into two classes based on the manner in which they attach themselves to glass surfaces: the first type prefers smooth surfaces, and the second type prefers rough surfaces. Changes in the attaching property of the cell are associated with zygote formation - e.g. gametes of Acetabularia belong to the first type and mature zygotes to the second one. In green, brown and red algae both reaction types are observed in mobile and immobile cells. The adhesion process is temperature independent between 13 and 23°C. An influence of surface active compounds on the attachment process was observed; it was found that for example a Silicon film on the glass surface cancels differences in the attaching properties.The observations are believed to give some information on the surface properties of free-living unicellular stages of algae. These are discussed in connection with structural changes in the reacting surfaces during the pairing process and in connection with the first step in the settlement of epiphytic algae and the production of underwater fouling.