Final answer:
The removal of upper grass meristems stimulates axillary meristems, leading to an increase in tillers. Grasses have intercalary meristems, enabling regrowth after the tips are removed or damaged. This adaptation allows grasses to effectively recover from grazing or mowing.
Step-by-step explanation:
The removal of upper grass meristems typically stimulates axillary meristems (at the base of the stems) to become active, leading to an increase in the number of tillers. Meristems are regions of plant growth where cells actively divide to produce new tissues. Grasses have a special type of meristem known as the intercalary meristem, located at the base of leaf blades and nodes; this allows the plants to regrow even after the tips have been removed or damaged, as often happens with grazing or mowing.
Grasses exhibit primary growth only, which is driven by meristematic activity at the tips of the roots and shoots, including tillers. When the shoot's apical meristem is removed or damaged, the axillary meristems, which are generally suppressed by the apical dominance of the main stem, are released from this inhibition. As a result, they can become active and promote the growth of new tillers, enhancing the grass's ability to spread and utilize space and resources effectively.