Question

Which one of the following is not a characteristic of meristematic cells ? (a) Presence of intercellular spaces (b) Thin cellulosic cell walls (c) Presence of prominent nucleus (d) High metabolic rate

Short answer

Option (a) 'Presence of intercellular spaces' is not a characteristic of meristematic cells.

Step-by-step solution

Understanding Meristematic Cells

Meristematic cells are undifferentiated cells located in the meristems of plants where growth occurs. Key characteristics of these cells include being tightly packed with little or no intercellular spaces, thin and flexible cell walls to accommodate cell division, a prominent nucleus due to active cell division, and a high metabolic rate to drive growth.

Identify Non-characteristic Option

After understanding the characteristics of meristematic cells, we review the options to identify which one is not a characteristic. Options (b), (c), and (d) correspond to true characteristics of meristematic cells. Option (a) mentions the presence of intercellular spaces, which is not a characteristic of these cells since they are tightly packed.

Conclusion

Based on the characteristics of meristematic cells, option (a) 'Presence of intercellular spaces' is not a characteristic of meristematic cells, as they typically don't have intercellular spaces. The correct answer is therefore option (a).

Key concepts

Plant Growth and Development

Plant growth and development are fascinating processes that center around the activity of meristematic cells. These cells are the engine of plant growth, constantly dividing and differentiating to form various tissues and organs.

In plants, growth is not random but highly organized and occurs specifically at growth points known as 'meristems'. There are different types of meristems, such as apical meristems found at the tips of roots and shoots, and lateral meristems, which contribute to the growth in girth. Meristematic cells located at these sites have the unique ability to divide indefinitely, leading to the elongation of roots and shoots and increasing the plant's height and size.

For students studying plant biology, understanding that meristematic cells undergo rapid and perpetual cell division, Expansion, and differentiation is key to grasping the fundamentals of how plants grow and develop. These cells are vital because they give rise to various specialized tissues that form the complex architecture of a plant.

Cell Division in Plants

Cell division is a cornerstone of plant growth and a defining characteristic of meristematic cells. Unlike animal cells, which can divide throughout the entire organism, plant cells typically divide in specific regions containing meristematic cells.

The most common type of cell division in plants is mitosis, a process that ensures each new cell has the same number of chromosomes and roughly the same amount of genetic material as the parent cell. This process maintains the genetic consistency throughout the plant's life cycle.

Understanding mitosis involves recognizing the stages of the cell cycle—interphase, prophase, metaphase, anaphase, and telophase—alongside cytokinesis, which is the actual division of the cell’s cytoplasm. Key to this process are the characteristics of meristematic cells we've explored: their active metabolism, large central nucleus, and thin, flexible walls, which together facilitate swift and successive cell divisions necessary for plant growth.

Plant Tissue Types

Plants are composed of various tissue types, each with a distinct role in the plant's overall function and structure. Broadly, plant tissues can be categorized into three main types: meristematic, permanent, and reproductive tissues.

• Meristematic tissues, as discussed, are where active cell division occurs, leading to plant growth. These include apical, lateral, and intercalary meristems.
• Permanent tissues are derived from meristematic cells and have ceased to divide. They are specialized for various functions such as photosynthesis (parenchyma), support (collenchyma), and water transportation (xylem).
• Reproductive tissues give rise to flowers and seeds, enabling the plant to propagate its species.

Each tissue type originates from the division of meristematic cells, followed by cell differentiation, where cells become specialized in structure and function. The absence of intercellular spaces in meristematic cells highlights their difference from some permanent tissue types, like parenchyma, which may have intercellular spaces to facilitate gas exchange.