Changes in Proteins in Pistils after Self- and Cross-Pollination in Japanese Pear

Abstract

The present study was performed to get a clue to a solution for the obfuscating mechanism with reference to self-incompatibility in Pyrus serotina.
1. The growth of pollen tubes showed the slow rate from approximately 36 hours after pollination and stopped completely in 48 hours at the portion near the ovary in a selfed style, but the tubes in a crossed one continued their growth and fertilization occurred in about 96 hours after pollination.
2. In the selfed style, the tips of pollen tubes began to swell in 36 hours after pollination and callose deposited abnormally on the surface of the tubes. However, in a crossed style, sharp tips of the tubes and no abnormality of callose deposition were observed at above time.
3. Soluble proteins and proteins dissociated by Tween 20 in selfed pistils exhibited unchanged level till 48 hours after pollination and increased thereafter gradually. On the other hand, these in crossed pistils decreased leisurely up to 24 hours and displayed steep increase after that time.
4. In the fraction of proteins dissociated by Tween 20, both electrophoretic patterns of proteins from selfed and crossed pistils exhibited little difference till 72 hours after pollination. However, in the fraction of soluble proteins, band 7 peak from the selfed pistils increased the height in 24 hours after pollination and then decreased. The band 7 from the crossed pistils displayed reverse patterns compared with that from the selfed pistils, that is to say, the band 7 decreased in 24 hours after pollination and then continued to increase gradually. Band 7 from the non-pollinated pistils showed intermediate patterns between above bands from selfed and crossed pistils.