AUTORADIOGRAPHIC STUDIES OF METHIONINE INCORPORATION INTO AND EXCLUSION OF PECTIN FROM POLLEN TUBES OF VARIOUS ORNAMENTAL SPECIES

Pollen from certain ornamental species, specifically Liliaceae and Amaryllidaceae, responded physiological level of methionine and showed promotive growth effects in vitro, whereas some other species did not show much a methionine effect, if any at all.

When pollen from certain species demonstrated the promotive methionine effect, an addition of calcium (Ca) ions to the medium resulted in almost doubled length of pollen tubes.
Pectic substances on the tube wall were suggested to be the Ca-binding sites and become increased in this manner.
This was also suggested by cellulase digestion of pollen-tube walls having distinguishable retaining of the promotive Ca action, whereas pectinase lessened it drastically.
Ethionine greatly inhibited pollen growth, indicating the fact that it suppresses the methylation process leading to pectin synthesis occurring in growing pollen tubes.

Evidence from microautoradiography with ¹⁴C-methyl methionine indicated that the exclusive incorporation takes place in the pollen-tube wall as a pectin precursor.

Fruit Set and Development, XXI IHC

B.H. Kwack

https://doi.org/10.17660/ActaHortic.1983.139.2