ISA Certified Arborist Practice Exam

In botanical terms, what does the term "xylem" refer to?

1. The outer protective layer of the tree

2. The tissue responsible for nutrient transport

3. The tissue responsible for the transport of water and minerals from the roots

4. The storage area for carbohydrates in trees

The correct answer is: The tissue responsible for the transport of water and minerals from the roots

Xylem refers specifically to the tissue in vascular plants that is responsible for the conduction of water and dissolved minerals from the roots throughout the plant. This transport system plays a crucial role in maintaining the plant's hydration and overall health, allowing it to undergo photosynthesis and grow properly. Xylem is composed of various cell types, including vessel elements and tracheids, which are specialized for efficient water transport. As water evaporates from the leaves through a process known as transpiration, it creates a negative pressure that pulls more water up from the roots through the xylem. This process is vital for sustaining the life of the tree. Understanding the role of xylem enhances knowledge about how trees function and adapt to their environments, making this concept fundamental for those studying arboriculture or botany.