Pavement cells

Pavement cells are a type of cell found in the epidermis of plants. They are so named because of their interlocking, puzzle-piece shape, which resembles cobblestone pavement. Pavement cells are the most common type of epidermal cell and play a crucial role in protecting the plant from environmental stressors such as pathogens and physical damage. They also contribute to the regulation of gas exchange and water loss through the stomata, which are surrounded by specialized pavement cells known as guard cells.

Structure and Function

Pavement cells are characterized by their irregular shape and the presence of interdigitating lobes and indentations. This complex shape increases the surface area for light absorption and helps in the distribution of mechanical stress across the cell. The cell wall of pavement cells is composed of cellulose, hemicellulose, and pectin, with regions of varying thickness that contribute to the cell's flexibility and strength.

The primary function of pavement cells is to form a protective barrier against physical damage and pathogen invasion. Their interlocking pattern strengthens the cohesion between cells, enhancing the structural integrity of the epidermis. Pavement cells also play a role in water conservation by minimizing water loss through the epidermis, except at the stomatal openings where gas exchange occurs.

Development

The development of pavement cells is a highly regulated process that involves the coordination of cell growth and division. Key regulatory genes and signaling pathways, such as those involving plant hormones like auxin and cytokinin, have been identified in the control of pavement cell shape and patterning. The Rho of plant (ROP) signaling pathway, in particular, is crucial for the establishment of cell polarity and the formation of the interdigitating cell pattern.

Research and Applications

Research on pavement cells has provided insights into the mechanisms of cell shape determination and the role of the epidermis in plant defense and water regulation. Understanding the genetic and molecular basis of pavement cell development has potential applications in agriculture, such as engineering crops with improved resistance to environmental stressors.

See Also

• Epidermis
• Cell wall
• Guard cell
• Stomata
• Plant hormone