Final answer:
Cutting off the top of a grass stem does not remove all the meristems due to the presence of intercalary meristems located above each node. These intercalary meristems allow the grass to resume growth and replace lost photosynthetic area. This adaptation is important for grasses to continue growing even after grazing or mowing.
Step-by-step explanation:
When the top of a grass stem is cut off, not all of the meristems are removed because there is an intercalary meristem located above each node. These intercalary meristems are present in grass leaves and allow the leaf to resume growth and replace lost photosynthetic area. This is an important adaptation for grasses, as it allows them to continue growing even after grazing or mowing.
Intercalary meristems occur in monocots, such as grasses, and are located at the nodes of stems and at the base of the grass leaf blade. These meristems are activated when the stem or leaf above them is damaged. They enable the grass leaf blade to increase in length from the base, allowing grass leaves to elongate even after repeated mowing.
So, cutting off the top of a grass stem does not remove all the meristems, and growth can still occur from the intercalary meristems located above each node.