Britannica
Sources used in this answer
Why can most plants continue growing throughout their life spans?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
plant development
The life cycle of the fern. (1) Clusters (sori) of sporangia (spore cases) grow on the undersurface of mature fern leaves. (2) Released from its spore case, the haploid spore is carried to the ground, where it germinates into a tiny, usually heart-shaped, gametophyte (gamete-producing structure), anchored to the ground by rhizoids (rootlike projections). (3) Under moist conditions, mature sperm are released from the antheridia and swim to the egg-producing archegonia that have formed on the gametophyte's lower surface. (4) When fertilization occurs, a zygote forms and develops into an embryo within the archegonium. (5) The embryo eventually grows larger than the gametophyte and becomes a sporophyte.
Unlike most animals, plants are capable of growing throughout their entire life spans due to the presence of meristems. These are specialized regions of intensely active, undifferentiated cells that serve as permanent sources of new cell production.12345
The ability to grow indefinitely is driven by the following mechanisms:
- Continuous Cell Division: Within meristems, cells known as initials undergo mitosis repeatedly. When an initial divides, one daughter cell remains in the meristem to maintain the population, while the other is displaced to differentiate into the specific tissues required for the plant's development.1345
- Types of Meristems:
- Apical meristems are located at the tips of roots and shoots, facilitating primary growth and the extension of the plant body.135
- Lateral meristems (such as the cambium and cork cambium) are responsible for secondary growth, which increases the girth and thickness of stems and roots.412
- Intercalary meristems contribute to the extension of specific structures, such as the stems of grasses.412
Through these localized zones of division, plants maintain the capacity for ongoing development and organ formation throughout their lives.42