plant transport

• in plants, the roots move water by osmosis
• the symplast pathway is when water moves down the concentration gradient by diffusion from root hair cells to xylem and moves through plasmodesmata
• the apoplast pathway is when water is moved by the attraction of water molecules across adjacent cell walls. the water and minerals are transported until it reaches the casparian strip
• the casprian strip is a waterproof layer that can let substances enter to cytoplasm with the help of active transport
• translocation of water takes place in the xylem and is the uptake of minerals and water
• translocation of water can be an active process as there is greater resistance to move through the xylem
• transpiration is the loss of water vapour through the surface of the plant
• movement of water in the xylem depends on transpiration then moves into the spongy mesophyll layer through osmosis
• tension is formed when water leaves the xylem to enter cells and goes all the way down to the roots
• tension is formed due to the cohesion of water. the polar nature means water molecules stick and create high tensile strength
• molecules adhere strongly to the walls of xylem and pores in cellulose cell walls. these forces pull water in the xylem upwards and then leaves plants through transpiration
• stomata opens in the light and mostly closed at night. transpiration rate increases until all stomata is open

  
• at a certain light intensity, an increase of temperature means increased amount of evaporation from the spongy mesophyll layer

  
• high air humidity lowers transpiration because of the reduced concentration gradient inside of the lead and air

  
• greater wind speed means that the shell of still air around the stomata is reduced so increases diffusion rates across membranes