Answer the following questions: 1. Why are xylem cells mostly dead? 2. Are phloem cells alive? 3. Can the phloem transport materials other than sugars? 4. How does water move in the xylem? 5. What happens if the phloem is damaged?
Answer (1)
Why are xylem cells mostly dead?
Xylem cells are mostly dead because they need to be hollow to efficiently transport water and nutrients from the roots to the rest of the plant. As xylem cells mature, they lose their cellular contents and become a series of connected, tube-like structures. This allows water to flow freely through them without any obstructions, facilitating efficient transportation.
Are phloem cells alive?
Yes, phloem cells are alive. The main components of the phloem, like sieve tube elements, are living cells that facilitate the transport of organic nutrients, particularly sugars, throughout the plant. These cells maintain their cytoplasm, enabling them to actively load and unload materials as needed.
Can the phloem transport materials other than sugars?
Yes, the phloem can transport materials other than sugars. It also carries amino acids, hormones, and other organic molecules essential for plant growth and functioning. The phloem acts as a transportation highway, moving various nutrients and signaling compounds throughout the plant.
How does water move in the xylem?
Water moves in the xylem through a process called transpiration. As water evaporates from the leaves, it creates a negative pressure that pulls more water upwards through the xylem from the roots. This movement is also aided by capillary action and the cohesion of water molecules.
What happens if the phloem is damaged?
If the phloem is damaged, the plant can have difficulty distributing essential nutrients, leading to disrupted growth and potentially death. Severed phloem disrupts the transport of sugars from the leaves to where they are needed in other parts of the plant, starving regions of energy and necessary compounds.
