Explain why the leaves in girdled trees are still able to receive mineral ions from theroots.

Girdling, also known as ring-barking, is the process of removing a ring of bark from a tree. This process interrupts the flow of nutrients and water in the tree's vascular system, specifically the phloem, which transports sugars and other metabolic products downwards from the leaves. However, it does not affect the xylem, which transports water and mineral ions upwards from the roots.

Here are the steps explaining why the leaves in girdled trees are still able to receive mineral ions from the roots:

1. The tree's roots absorb water and mineral ions from the soil. This is a process that is not affected by girdling.

2. These water and mineral ions are transported upwards through the xylem vessels, which are part of the tree's vascular system. The xylem vessels are located inside the tree, deeper than the phloem, so they are not affected by the girdling process.

3. The water and mineral ions reach the leaves, where they are used for photosynthesis and other metabolic processes.

4. Even though the downward transport of sugars and other metabolic products from the leaves is interrupted by the girdling, the upward transport of water and mineral ions from the roots is not. Therefore, the leaves are still able to receive these necessary substances.

5. However, it's important to note that while the leaves can still receive water and mineral ions, the tree overall will be negatively affected by the girdling process. The inability to transport sugars and other metabolic products from the leaves to the rest of the tree will eventually lead to the tree's death.