Picture of the Day

Tubes From Pollen Headed For An Egg Cell

Pictured here are pollen tubes emerging from pollen grains on the stylar surface of Austrobaileya scandens, a vine endemic to the Australian rainforest. The stigma is the part of the flower that receives pollen, and it can be very far from the egg.

The pollen tubes exit the pollen grain from a slit-like opening that can be most clearly seen in the pollen grain on the right side. The tubes are about 10 microns (one one hundredth of a millimeter) wide, but they can grow well over 6 millimeters to reach an egg, all in less than 24 hours after pollination, which is when this photo was taken.

Visit Website | Image credit: Joseph H. Williams, Department of Ecology and Evolution, University of Tennessee