CYTOCHEMICAL IMMUNOLOCALIZATION OF THE ABUNDANT PISTIL PROTEIN S(K2) IN POTATO (SOLANUM-TUBEROSUM)

S-k2 protein is the most abundant member of the pistil-specific protei ns of Solanum tuberosum. S-k2 protein has been localized by use of a p olyclonal antibody (anti-S-k2) in the pistils of four clones of Solanu m tuberosum. In the stigmas S-k2 protein accumulates to a high level i n the cytoplasm of the internal secretory cells underlying the papilla e one day prior to anthesis. In styles, the intercellular matrix of th e transmitting tissue cells is intensely labelled by anti-S-k2. S-k2 p rotein is present in all four clones and shows the same labelling patt ern. The possible role of the S-k2 protein in pollen tube growth is di scussed.