Appearance of vegetative propagules from nodes of plant such as sugarcane and ginger is mainly because: 

Nodes have meristematic cells

Vegetative propagation is asexual reproduction from various parts in plants. In plants, such as, sugarcane and ginger, appearance of vegetative propagules from nodes is because of presence of meristematic cells in them. Meristematic cells have the ability to divide to form new cells which can differentiate and given rise to permanent tissues.