Ch. 8 - Transport in Plants

Function - transport water and minerals throughout the plant Features - 1. Unidirectional 2. Dead cells - have no cell contents 3. Cells are joined end to end with no cross walls to form a long continuous tube 4. Thick walls with lignin - to ensure the plant does not collapse (Lignin is mainly present in wood and stem part of the plant)

Function - transport food and nutrients throughout the plant Features - 1. Bidirectional 2. Living cells - have cell organelles 3. Mainly carries sucrose and amino acids (products of photosynthesis) 4. The process where phloem carries sucrose and amino acid from photosynthesis across the plant is known as translocation.

Soil to root hair cells to root cortex cells to xylem where it diffuses up to the cells in the leaf and leaves the leaf through evaporation.

Transpiration refers to the loss of water from the plant in the form of water vapour through the stomata.

Transpiration pool is a suction range by the loss of water from transpiration, leading to a pool like force. It is supported by the cohesion between water molecules. It follows the principle of capillary reaction.

• Wind • Humidity • Temperature • Opening and closing of the stomata

If there is too much water loss, the plant cells will become flaccid and will cause wilting of the plant. Water loss will only cause wilting if there is insufficient water in the soil.

Translation refers to the movement of sucrose and amino acids (products of photosynthesis) in the flow from sources to sinks

Sources - part of the plant that release sucrose or amino acids Sinks - part of the plant that uses or stores sucrose or amino acids

Sucrose and amino acids may move in different direction due to the growth stage of the plant or the specific time of the year.

If the air bubble moves, we know that transpiration has occurred. The more the air bubble travels - the higher the transpiration rate.