Key terms

• What is the function of xylem in plants?

  Transports water and minerals
• What does phloem transport?

  Organic substances like sucrose
• What is a vascular bundle?

  A structure containing xylem and phloem
• What is the stele in plant roots?

  The central part containing vascular tissue
• What is the role of the endodermis?

  Surrounds the vascular bundle in roots
• What is the Casparian strip?

  A waterproof band in the endodermis
• What does the pericycle do?

  Gives rise to lateral roots
• What is the function of cambium?

  Responsible for secondary growth
• What is transpiration in plants?

  Loss of water vapor from leaves
• What does the cohesion-tension theory explain?

  Water movement through xylem
• What is capillarity in relation to water?

  Water rising in narrow tubes
• What causes root pressure?

  Active transport of ions into xylem
• What is the function of the Casparian strip?

  Forces water through the symplast pathway
• What is the apoplast pathway?

  Water movement through cell walls
• How does the symplast pathway function?

  Water moves through cytoplasm via plasmodesmata
• What is the vacuolar pathway?

  Water movement through vacuoles and cytoplasm
• What are stomata?

  Pores that regulate gas exchange
• What is the role of guard cells?

  Control opening and closing of stomata
• What is the cuticle on leaves?

  A waxy layer that reduces water loss
• What is a potometer used for?

  Measuring the rate of transpiration
• What does wilting indicate in plants?

  Loss of turgor pressure
• What is a xerophyte?

  A plant adapted to dry environments
• What is a hydrophyte?

  A plant adapted to aquatic environments
• What is a mesophyte?

  A plant adapted to moderate water availability
• What is translocation in plants?

  Movement of organic substances through phloem
• What is a source in plant transport?

  Part that produces and exports sugars
• What is a sink in plant transport?

  Part that imports and stores sugars
• What does the mass flow hypothesis explain?

  How solutes are transported in phloem
• What is active loading in plants?

  Transporting sucrose into sieve tube elements
• What are sieve tube elements?

  Main cells of the phloem
• What are companion cells?

  Cells that provide ATP to sieve tube elements
• What are plasmodesmata?

  Small channels between plant cells