22 April 2011
Vol 332, Issue 6028

About The Cover

Cover image expansion

COVER False-colored two-photon microscopy image showing green fluorescent protein–labeled pollen on the stigma (the top of the pistil) of Arabidopsis thaliana. On page 434, Michard et al. describe a plant signaling mechanism that directs the growth of pollen tubes, which carry sperm cells to the ovule at the base of the pistil, and that is analogous to amino acid–mediated communication commonly observed in animal nervous systems. Image: L. Boavida and J. A. Feijó, Instituto Gulbenkian de Ciencia and Universidade de Lisboa, Portugal