Rapid swelling of pollen grains in the dehiscing anther of two-rowed barley (Hordeum distichum L. emend. Lam.)

Abstract

The role of rapid swelling of pollen grains in anther dehiscence in Hordeum distichum L. emend. Lam. and the mechanism of this swelling were examined. Artificial opening of the floret induced rapid swelling of pollen grains and thecae dehiscence. The theca dehisced as pollen grains became swollen and dehisced anthers had larger pollen grains than indehisced anthers. Septa in the anther segments dehisced as a result of water-induced pollen pressure. These results strongly support the theory that the rapid swelling of pollen grains is a driving force for anther dehiscence. On the other hand, potassium was detected in pollen grains from dehisced anthers, but not in pollen grains in indehisced anthers. This suggests that potassium ions function as a turgor regulator in the rapid swelling of pollen grains. The mechanism of anther dehiscence is discussed in relation to the swelling of pollen grains, as is the possible mechanism of this swelling. (C) 2000 Annals of Botany Company.