STIGMATIC RNASE IN SELF-COMPATIBLE PEACH (PRUNUS-PERSICA)

In peach, which is self-compatible, the stigma was found to actively secrete RNase. This stigmatic RNase was developmentally regulated, reaching maximum activity at the beginning of anthesis. A major 21-kD stigmatic RNase was detected by SDS-PAGE. Both this 21-kD stigmatic RNase and pancreatic RNaseA significantly inhibited pollen germination and pollen tube length in vitro. Pollen tube length was fully recovered in the presence of RNA as a competitive inhibitor of the 21-kD stigmatic RNase. These in vitro studies appear to indicate that in peach, the 21-kD RNase plays a role in the pollination process.