Question

Which is/are correct statement/s?

• A. In flowering plants, tracheids and vessels are the main water transporting elements.
• B. In gymnosperms, tracheids are the chief water transporting elements
• C. The companion cells play an important role in the maintenance of a pressure gradient in the sieve tubes
• D. All of these

Answer 1

Answer: (D)

Gymnosperms lack vessels in their xylem. Tracheids are elongated or tube-like cells with thick and lignified walls and tapering ends. These are dead and are without protoplasm. The inner layers of the cell walls have thickenings which vary in form. In flowering plants, tracheids and vessels are the main water transporting elements. The vessel is a long cylindrical tube-like structure made up of many cells called vessel members, each with lignified walls and a large central cavity.
Companion cells, along with phloem parenchyma play an important role in the maintenance of a pressure gradient in the sieve tubes.