3.3 transport in plants

• Xylem vessels are dead cells with thickened walls that prevent them from collapsing under pressure.
• Active loading involves "loading" of sugars into the sieve tubes of the phloem tissues, requiring ATP.
• Translocation is the movement of sugars and amino acids from the leaves to the rest of the plant
• Preventions of water loss by plants are waxy cuticle, losing leaves in winter, and stomata closing
• Xerophytes are plants adapted to live in dry environments, such as cacti.
• A potometer is a device used to measure the rate of transpiration from a plant.
• Environmental factors that effect transpiration are temperature, light intensity, humidity, wind speed and wind direction
• Transpiration is the loss of water vapour from the stomata of a plant
• The casparian strip is a layer of cells that is impermeable to water and solutes
• Root hair cells have a specialised exchange surface for water uptake
• The apoplast pathway is the pathway that transports substances from the cell to the rest of the plant, moving by mass flow.
• the symplast pathway is the pathway of the xylem cells that carry water and mineral ions
• The three water transport pathways through a plant are: symplast pathway, vacoular pathway and apolplast pathway.
• Phloem are the cells that transport sugar from the leaves to the rest of the plant.
• Xylem are dead cells that are hollow and have no chloroplasts. They transport water and mineral ions
• meristem: a region of plant tissue, found at the growing tips of roots and shoots and in the cambium, consisting of actively dividing cells forming new tissue
• vascular tissue: consists of cells specialised for transporting fluids by mass flow