Why do most plants continue growing throughout their lives?

Unlike most animals, which typically reach a mature size and stop growing, most plants continue to grow throughout their entire lives because they remain perpetually embryonic. This ability is primarily due to the activity of meristems, which are specialized regions of undifferentiated cells capable of continuous division.1234

These meristematic regions function as follows:

• Persistent Growth: Within meristems, cells undergo mitosis to produce new cells. In persistent meristems, one daughter cell remains meristematic to continue the cycle, while the other differentiates into specialized tissues, allowing the plant to add new organs and increase in size indefinitely.345
• Types of Meristems: Apical meristems at the tips of roots and shoots drive primary growth (extension), while lateral meristems are responsible for secondary growth, increasing the girth and thickness of stems and roots.42
• Cellular Processes: Beyond cell division, plant growth is supported by the ability of individual cells to enlarge, facilitated by elastic cell walls, and by the influence of internal hormones such as auxin, cytokinins, and gibberellins.2