Root Hairs and Water Absorption in Plants PDF

How root hairs absorb water Plants, like all living things, are made mostly of water. Plants need to absorb water almost all of the time. They do this through their roots. The roots absorb water from the soil. Soil is made up of tiny particles of rock. The particles are usually irregularly shaped, a...

How root hairs absorb water Plants, like all living things, are made mostly of water. Plants need to absorb water almost all of the time. They do this through their roots. The roots absorb water from the soil. Soil is made up of tiny particles of rock. The particles are usually irregularly shaped, and all sorts of different sizes. They do not pack together tightly. There are spaces between them, which are filled with air and water. You may remember that special cells called root hairs grow out of the surface of roots, Root hair cells provide a really big surface through which water and mineral ions can be absorbed into the plant. This photograph of root hairs was taken with a microscope. Root hairs are very tiny, but you can just see them without using a lens. This diagram shows a root hair growing in between soil particles. Each root hair is part of a single cell. Water moves into the root hair cell from the soil. It passes through the cell wall and the cell membrane of the cell, and into the cytoplasm. Minerals, including magnesium and nitrate, also move into the root hair cell, along with the water. Magnesium and nitrate are in the form of ions (see Topic 2.4), dissolved in the water between the soil particles. moist soll pothair cell particles cells Inside root nucleus cell wall cell membrane vacuole containing cell sap cytoplasm How water moves up the plant This diagram shows what a root looks like if you cut it across. You can see the root hairs on the outside of the root. In the centre, there are some very special cells called xylem vessels. These are the water transport system of the plant. After water has been absorbed into a root hair cell, it moves from the outside of the root towards the inside. It goes into the xylem vessels in the centre of the root. Xylem vessels are long, tube-like cells. They are dead cells-all of their contents, such as cytoplasm and a nucleus, have disappeared. All that is left is their cell walls, with an empty space inside. Their end walls have completely disappeared too. Many xylem vessels stack on top of one another, making long, empty tubes that reach all the way from the to the highest parts of the plant. roots, up The wood in a tree trunk is made up of xylem vessels. They carry water from the roots all the way to the top of the tree. This photograph shows some xylem vessels. It has been taken with a microscope. The actual diameter of a xylem vessel is only about 0.05 mm --although, as you can see in the photograph, they come in a range of different sizes a xylem vessel, which transports the plant cross shaped ama where xylem bound root hat, for absorbing water and minerals root cap that protects the tip of the root ast grows through the sol.Xylem in roots and stems These two diagrams show the position of xylem in the roots (left) and stems (right) of a plant. They are cross-sections -you are looking down on a cut surface across a root and across a stem. The xylem vessels are shown in red.