key term - Plasmodesmata

Definition

Plasmodesmata are microscopic channels that traverse the cell walls of plant cells, allowing for direct communication and transport between adjacent cells. They play a crucial role in the plant's ability to share nutrients, signaling molecules, and other substances, facilitating a coordinated response to environmental changes.

5 Must Know Facts For Your Next Test

1. Plasmodesmata are formed during cell division when the primary cell wall is laid down, creating channels that connect the cytoplasm of neighboring cells.
2. Each plasmodesma is lined with plasma membrane and contains a narrow strand of cytoplasm called the desmotubule, which connects to the endoplasmic reticulum.
3. They allow for the movement of small molecules like ions, sugars, and hormones, as well as larger signaling molecules, enhancing intercellular communication.
4. Plasmodesmata can change their permeability in response to developmental cues or environmental stresses, affecting how substances are shared among cells.
5. In some cases, viruses exploit plasmodesmata to spread from one cell to another, illustrating their role in both plant health and disease.

Review Questions

• How do plasmodesmata facilitate communication between plant cells?
  • Plasmodesmata serve as direct pathways between adjacent plant cells, allowing for the movement of nutrients, hormones, and signaling molecules. By connecting the cytoplasm of neighboring cells, they enable a rapid response to environmental changes and promote coordination in plant growth and development. This direct communication is essential for processes such as resource sharing and stress responses.
• Discuss the structural components of plasmodesmata and their significance in plant physiology.
  • Plasmodesmata consist of a channel lined with plasma membrane that connects the cytoplasm of adjacent cells. Inside this channel is a desmotubule derived from the endoplasmic reticulum. The structure allows for selective transport of various molecules between cells, supporting vital physiological functions like nutrient distribution and stress signaling, thereby enhancing overall plant health.
• Evaluate the implications of plasmodesmata in plant responses to pathogens and environmental stress.
  • Plasmodesmata play a dual role in plant responses; they facilitate intercellular communication that can enhance defense mechanisms against pathogens while also serving as entry points for some viruses. Environmental stresses can cause plasmodesmata to alter their permeability, affecting how effectively plants share resources and signals during stress responses. Understanding this dynamic can help in developing strategies for improving plant resilience against diseases and environmental challenges.

Related terms

Cell wall:

A rigid outer layer that provides structural support and protection to plant cells, composed mainly of cellulose.

Cytoplasm:

The gel-like substance within the cell membrane where cellular processes occur and organelles are located.

Symplastic pathway: A route for water and solute movement through the cytoplasm of interconnected cells via plasmodesmata.