Plant cells often contain ergastic substances , crystals or other deposits of various chemicals. These may be found in the vacuole or the cytoplasm. The compounds involved have a variety of functions. Some ergastic bodies are simply stored food, while others contain compounds known to be repellent or toxic to herbivores. Rip a Zebrina leaf and examine.
Many cells contain stacks of needle-shaped raphides .
A thin section through a Begonia stem will show more rounded crystals, known as druses . Compared to most animals, vascular plants are quite simple in structure. The leaves plus the shoots make up the shoot system , while the roots collectively compose the root system . The arrangement of structures in the shoot system is very stereotyped, and hardly varies despite the great diversity in appearance and growth form of vascular plants. Shoots are constructed in modular fashion, with the basic module being composed of a leaf and a length of stem.