Pollen coat signals with respect to pistil activation and ovule penetration in Gasteria verrucosa (Mill.) H. Duval

In the pistil of Gasteria there is an activation by pollen coat proteins leading to water uptake of the pistil. This enhances the growth of pollen tubes of cross pollen. It also activates the ovule to attract the pollen tube. This may be a result of the exposition of the micropylar exudate with the attractant. The micropylar exudate attracts one or more pollen tubes. In vitro tubes may stop before they enter the micropyle which is marked by a swelling of the pollen tube tip. Thereafter they penetrate the funnel shaped micropyle.