For example, spines, thorns, and prickles are all sharp plant parts that protect the plant from herbivores. Plant growth is fundamentally different from animal growth. In other words, the overall shape of the adult animal is genetically determined from its earliest developmental stages. Once an animal has become an adult, it may become heavier or fatter, but it will not become larger. Thus the overall shape of the plant is not determined in advance, and the growth is said to be indeterminate.
Meristems are regions of embryonic tissue capable of growing into new plant parts.
Meristems are found in both roots and shoots. Primary meristems make the shoot or root grow longer. This kind of growth is called primary growth. A shoot apical meristem is found within each bud. A root apical meristem is found at the tip of each root, and is protected by the root cap.