mass transport in plants

• Plants have transport systems because they have a smaller surface area to volume ratio. The need water, minerals and sugars to survive so a transport system moves these substances around the body, it also removes waste. 
• Plants with specialised transport systems are called vascular plants. 
• Xylem - water and mineral ions 
• Phloem - organic substances (sucrose) 
• Transpiration pull is the loss of water by evaporation in the mesophyll layers which generates a negative pressure at the top of the xylem pulling the water up.
• Cohesion is water being a polar molecule that forms hydrogen bonds. 
• Adhesion is when water forms hydrogen bonds with cellulose in the xylem lining. 
• Root pressure is the weakest force, it is the pressure generated when water moves into the roots by osmosis. 
• phloem cell

  A) pit

  B) thick cell wall

  C) empty space

  D) cell wall gap

  
• xylem cell walls are made of cellulose and lignin