water flow through plants

water flow through plants

1. transpiration rate is increased by four main things

   • light intensity
     • The brighter the light, the greater the transpiration rate. Stomata begin to close as it gets darker. Photosynthesis can't happen in the dark, so they dont need to be open to let co2 in. When stomata are closed, water can't escape
   • temperature
     • The warmer it is, the faster transpiration happen. When it's warm the water particles have more energy to evaporate and diffuse out of the stomata
   • air movement
     • If there's lots of air movement (wind) around a leaf, transpiration happens faster. If the air around leaf is very still, the water vapour just surrounds the leaf and doesn't move away. This means there's a high concentration of water particles outside the leaf as well as inside it, so diffusion doesn't happen quickly. If it's windy, the water vapour is swept away, maintaining a low concentration of water in the air outside the leaf. Diffusion then happens quickly, from an area of high concentration to an area of low concentration
   • air humidity
     • If the air around the leaf is very dry, transpiration happens more quickly. This is like what happens with air movement. If the air is humid there's a lot of water in it already, so there's not much of a difference between the inside and the outside of the leaf. Diffusion happens fastest if there's a really high concentration in one place, and a really low concentration in the other

2. Stomata open when the guard cells become turgid and closes when they become flaccid