Ricerc@Sapienza

All tissues and organs in vascular plants derive from a pool of undifferentiated,
totipotent cells known as stem cells that divide repeatedly and asymmetrically to
feed a growing organ with newly amplified cells. The evolution of stem cells and
their organization
within meristems of different types allowed the diversification
of vascular
land plant species, which have spread and diversified since the mid-Devonian
period (about 400 Mya).
Stem cells are set aside very early during de novo organogenesis to sustain