7.1 - Transport in plants Flashcards
What is the function of the xylem?
They are vessels that transport water and minerals from the roots to the stem and leaves.
What is the function of the phloem?
They are vessels that transport food materials (mainly sucrose and amino acids) made by the plant from photosynthesising regions in the roots and stem.
What are root hair cells and their functions?
They are single-celled extensions of epidermis cells in the root. They grow between soil particles and absorb water and minerals from the soil through osmosis (soil water has higher water potential than cytoplasm of root hair cell).
How does a root hair cell’s surface area impact osmosis?
The root hair increases the surface area of the cells, which is important because it increases the rate of absorption of water by osmosis and mineral ions by active transport.
What is the pathway of water through the plant?
Osmosis causes the water to pass into the root hair cells through the root cortex into the xylem vessels. It is then carried up to the leaves to enter the mesophyll cells.
What is transpiration?
Loss of water vapour from plant leaves by evaporation of water at the surfaces of the mesophyll cells followed by diffusion of water vapour through the stomata.
How is a transpiration stream created?
Water molecules are attracted to each other by cohesion, creating a continuous column of water up the plant. It moves through the xylem vessels in a continuous transpiration stream from roots to leaves via the stem. Transpiration produces a tension or pull on the water in the xylem vessels by the leaves.
How do temperature and humidity affect transpiration rate?
Transpiration increases with increasing temperature and decreases with increasing humidity.
What are the soluble products of photosynthesis?
Sugars (mainly sucrose) and amino acids.
How are soluble products of photosynthesis transported in the plant?
Through the phloem tubes (made of living cells), which are joined end to end and contain holes in the end cell walls to allow easy flow of substances.
What is translocation?
The transport of sucrose and amino acids in phloem, from regions of production to regions of storage or use.
