They are very active and have dense cytoplasm for rapid division.
Explanation
Meristematic tissues are composed of immature, undifferentiated cells capable of continuous division. These cells are responsible for the growth of the plant in length and girth. Their structural characteristics are directly adapted to facilitate rapid cell division and high metabolic activity.
Analysis of Characteristics:
- High Metabolic Activity: Meristematic cells are metabolically very active. They possess a dense cytoplasm and a prominent, large nucleus to control the rapid division process.
- Absence of Vacuoles: Vacuoles in mature plant cells provide turgidity and serve as storage for nutrients and waste. Meristematic cells do not require storage as they utilize nutrients immediately for energy and synthesis of new protoplasm. Additionally, a large central vacuole would physically hinder cell division (specifically cytokinesis). Therefore, vacuoles are either absent or extremely small.
- Cell Wall Nature: These cells have thin, elastic primary cell walls made of cellulose to allow for easy division and expansion. They do not have thick walls.
- Living State: Meristematic cells are living cells. Dead cells, such as sclerenchyma, cannot divide.
Key Takeaway:
Meristematic cells lack vacuoles because their primary function is rapid division, requiring dense cytoplasm and immediate resource utilization rather than storage or structural turgidity.