Plant Biology: Xylem and Phloem

What is the main function of xylem vessels in plants?

What is unique about the structure of xylem cells?

In which direction does water flow through the xylem?

What is the function of root hairs in plant water transport?

What is the composition of phloem tissue?

In which direction can materials flow through the phloem?

What is the purpose of translocation in plants?

Where are the xylem and phloem found in the root?

What is the main function of the layer of cells that separates the stele from the cortex?

In which part of the root do water and dissolved minerals enter the plant?

What is the reason for the high surface area of root hair cells?

Which process allows mineral ions to enter the root hair cells against their concentration gradient?

What is the shape of the xylem within the stele?

In leaves, which side of the bundle contains the phloem?

Why do root hair cells constantly need to be replaced?

What is the direction of water movement in the root hair cells?

Plant Transport Systems

Plants need to transport materials throughout their body, with a single tree capable of transporting thousands of liters of water from the soil every day.
Xylem vessels transport water from the roots to the top of the plant, only moving in one direction: up.

Xylem

Xylem is made up of dead cells that form long, hollow tubes.
There are no end walls between the cells, and the cells have thick, strong walls that support the plant.
Xylem tissue is found in the center of the stele in the root, and in the inner side of the bundle in the stem.

Phloem

Phloem is made up of living cells, allowing materials to flow in two directions.
Cells have end walls with holes, facilitating the flow of fluid containing sucrose and amino acids.
Materials can travel up or down through phloem, depending on the location of the leaf and where materials are needed.

Root Structure

The root has an inner, central part called the stele, surrounded by an outer part called the cortex.
The stele is separated from the cortex by a layer of cells that controls the flow of water into the xylem.
Xylem is found in the center of the stele, and phloem is found further out.

Water and Mineral Uptake

Water and dissolved minerals enter the plant through root hair cells, which are epidermal cells in a section of the root behind the growing tip.
Root hair cells have a large surface area, allowing for easy water uptake by osmosis.
Mineral ions are taken in by active transport, requiring energy to increase their concentration inside the root hair cells.

Understanding plant transportation systems, including xylem and phloem, is crucial in biology. Discover how plants transport water and dissolved substances.