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a) Transpiration is the process by which plants lose water vapour; from their surface into the atmosphere. {NB [mark as a whole] REJ If wrong spelling of key words}
b) REJ IN WHOLE If the stated action is not related to stomatal aperture size, temperature, light intensity and when the above are not adequately supported.
i) -Rate of transpiration is low; due to low light intensity at low temperatures;
Low rate of photosynthesis; low concentration of glucose; less turgidity of guard cells.
-Hence fewer stomata are open and have small apertures and the rate of evaporation is low owing to low temperature.
ii) Rate of transpiration increases rapidly with the time of the day; between 6am-noon; light intensity increases; thus, increasing production of glucose in guard cells which by osmosis draw in water hence increasing turgidity of the guard cells and consequently the number of stomata opened and increasing size of stomatal apertures.
-At around noon, too much water lost by the leaves lead to guard cells losing a bit of their turgidity hence reduction in stomatal aperture size and lowered rate of transpiration.
iii) Rate of transpiration decreases with increase in time of the day; due to decreased light intensity; and temperatures which lead to a decrease in the size of stomatal apertures and lowered rate of evaporation.
Kavungya answered the question on June 14, 2019 at 13:28
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