[Campbell Biology P.814] The secondary walls of tracheids and vessel elements are hardened w... | Practice Question

The secondary walls of tracheids and vessel elements are hardened with lignin. What is the primary advantage of this structural feature in water transport?

  • A: It allows for active transport of water against gravity.
  • B: It increases the flexibility of the cells, allowing them to bend with wind.
  • C: It provides support to prevent the collapse of the water-conducting tubes under the tension of water transport.
  • D: It regulates the flow rate of water by opening and closing pores.

Explanation

The text explicitly states: 'This hardening with lignin provides support and prevents collapse under the tension of water transport.' Water transport involves significant negative pressure tension , which could cause unsupported tubes to collapse.