Researchers discover what’s behind nature’s perhaps largest erection — which is not that big

In the plant kingdom, the sexual organ of a male pollen grain grows up to a thousand times its own length as it sniffs its way forth to a female egg cell to deliver its two sperm cells. Now researchers at the University of Copenhagen have advanced the understanding of what makes pollen ‘penises’, called pollen tubes, grow. The newfound knowledge may prove valuable to understanding human nerve cells.