1 Department of Life Sciences, University of Siena, 53100 Siena, Italy. giampiero.cai@unisi.it.
2 Department of Biological, Geological and Environmental Sciences, Alma Mater Studiorum University of Bologna, 40126 Bologna, Italy. stefano.delduca@unibo.it.
The pollen tube was a fundamental step forward in the evolution of terrestrial plants; in fact, it allowed plants to liberate themselves from water demand during reproduction [...].