Transporting water
Plants require transport systems to move water, dissolved food and other substances around their structures in order to stay alive.
Plants require water for two major reasons:
- For photosynthesis. In most flowering plants this happens in mesophyll cells in the leaves.
- To transport materials, eg Naturally occurring, inorganic chemical substances. Minerals are necessary for both plant and animal health..
Water taken up by the roots of a plant is transported through a plant to the leaves where some of it passes into the air. The stages of the process are:
1. Soil to xylem
- Water enters A specialised cell that increases the surface area of the root epidermis to improve the uptake of water and minerals.: tiny hairs covering the ends of the smallest roots. They provide a large surface area for the absorption of water by the process of osmosis.
- Water then moves from cell to cell through the root cortex by osmosis down a concentration gradient. This means that each cell has a lower water concentration than the one before it.
- In the centre of the root the water enters the xylem vessels - vein-like tissues that transport water and minerals up a plant.
2. Xylem to leaf to air
Water molecules move up the Narrow, hollow, dead tubes with lignin, responsible for the transport of water and minerals in plants. to the leaves where they exit and move from cell to cell. Water moves from the xylem vessels into the mesophyll cells where it can be used for photosynthesis.
Some of the water evaporates into the surrounding air spaces inside the leaf and then diffuses out through the Tiny holes in the epidermis (skin) of a leaf. They control gas exchange by opening and closing and are involved in loss of water from leaves. Singular is stoma. into the surrounding air. The opening and closing of the stomata is controlled by guard cells in the epidermis.
Watch the video below to see how to prepare a leaf slide to investigate stomata under a microscope.
