Igcse Model Questions Vol1 2018 Biology Question 5

A researcher is studying water movement in a mature bean plant (Phaseolus vulgaris) grown in a pot. The plant is watered with 500 mL of water at the start of the experiment. Over the next 72 hours the following observations are recorded: - The soil moisture sensor shows that the water content of the soil has fallen by 150 mL. - A potometer attached to the stem records a total water loss of 120 mL. - The fresh weight of the plant increased by 20 g (assume 1 g ≈ 1 mL water taken up for growth). The ambient temperature during the experiment was 25 °C and relative humidity 60 %. The researcher knows that, for this species, the rate of transpiration increases by about 10 % for each 1 °C rise in temperature, all other factors being constant.