GROWTH OF CROSS‐ AND SELF‐POLLEN TUBES IN THE STYLES OF BRASSICA OLERACEA

Abstract

SUMMARYIncompatible pollen tubes grew at approximately the same rate as compatible pollen tubes in the styles of Brassica oleracea. This is further evidence that in this species the chief barrier to the growth of incompatible pollen tubes is the stigmatic surface and that there is no positive inhibition of incompatible pollen tubes in the style. There were usually very many more pollen tubes at the top of the style than at its base, which indicated considerable variation in growth rate between the pollen tubes in a single style. The fastest pollen tubes in a style typically had a growth rate of 0.40–0.70 mm/h but the mean rate of growth was 0.14–0.34 mm/h.