Complex sentence: Auxin is also believed to play a part in the shedding of leaves and there color change in the fall in woody plants, when the abscission zone or layer cuts off the movement of auxin from the leaf blade to the leaf.
Split into simpler sentences: Auxin is also believed to play a part in the shedding of leaves and their autumn color change. In woody plants preparing to shed their leaves, the abscission zone or layer cuts off the movement of auxin from the leaf blade to the leaf.