[Campbell Biology P.840] The text mentions several structural features that facilitate bulk ... | Practice Question

The text mentions several structural features that facilitate bulk flow in plants. Which of the following correctly identifies such features? Select all that apply

  • A: The presence of abundant cytoplasm and organelles within sieve-tube elements.
  • B: The branching of veins in leaves, ensuring cells are close to vascular tissue.
  • C: Perforation plates at the ends of vessel elements.
  • D: Mature tracheids and vessel elements being dead cells with no cytoplasm.
  • E: Porous sieve plates connecting sieve-tube elements.

Explanation

The text explicitly mentions that 'the absence or reduction of cytoplasm in a plant's "plumbing" facilitates bulk flow through the xylem and phloem.' This includes mature tracheids and vessel elements being dead cells with no cytoplasm, and sieve-tube elements being almost devoid of organelles. It also states that 'Bulk flow is also enhanced by the perforation plates at the ends of vessel elements and the porous sieve plates connecting sieve-tube elements.' Lastly, 'the branching of veins ensures that no cell is more than a few cells away from the vascular tissue' facilitates efficient delivery.