24 August 2001
Vol 293, Issue 5534

About The Cover

Cover image expansion

COVER A pollen tube (blue), 10 mm in diameter, thrusting into the embryo sac (haploid female gametophyte; orange) of the flowering plant Torenia. The pollen tube is precisely attracted to the embryo sac by two synergid cells in the sac, enabling successful fertilization. 1480 [Scanning electron microscope image: T. Higashiyama and T. Kuroiwa]