2.55 Rate of transpiration

• Water lost from leave due to humidity, wind speed, temperature and light intensity. So, if we return to transpiration is the lost of water through the leave is cause by evaporation.
• The absorption of the sunshine generate the heat which transformed the water here in the leave into the gas face here above the Stamata pores, and then the important thing is the diffusion through the pores, so we need to think about the diffusion gradient from inside the pore in this region here and this region here. So, we call this one A and this one B.
• So, the concentration gradient for water vapor, if there’s a big different then we would have high rate of transpiration, if we the difference between A and B is small then we will have a low rate of transpiration.
• So, the factors that would cause a large different would be for instance if the humidity here is very low, and the second one would be if the wind blows away the water vapor here, that will keep the different large so, high wind.
• If the temperature is high will get more evaporation so, high temperature and the fourth one is light intensity so, if high light intensity will have high rates of photosynthesis and water movement.
• Low humidity, high wind, high temperature and high light intensity will all lead to large different in the concentration in A and B which will result in fast diffusion and high rate of transpiration.
• Conversely, if the different is small between A and B where humidity is high , where the wind speed is low, so high humidity around the Stamata pores the different will be small, the rate of diffusion will be small.
• If the wind speed is low that water vapor would built up around here, and the gradient is shallow, small again so that would be low rate of transpiration.
• Three low temperatures, low rate of evaporation and that will result a small different low rate but low light intensity and the rate of photosynthesis would be and slow and low. So the key features of understanding the rate of transpirations are the different between the concentration of the water here and here.
•  And how humidity, wind speed, temperature and light intensity effect transpiration depends on creating small and large differences here.