Biology 2016 JAMB Past Questions - Question 38: The rate of transpiration is NOT affected by

Correct Answer

A

Explanation

Options B,C and D affect thf rate of transpiration. A stoma consists of two guard cellswith an opening* called stomata! pore. The inner walls of the guard cells arethicker and elastic. This enables the guard cellste changes their shape, thusallowing opening and closing of the stomata! (pores found on the leaves andaerial parts of stems and branches of herbaceous plants.The guard cellshave. lots of chloroplasts that ensure high photosynthetic activity andconsequently exert high osmotic pressureon neighbouring epidermal cells. Waterflows into the guard cells by osmosis.The guard cells move away from each other and the stomatalpore opens Excess water is lost to the atmosphere by transpiration. The rate ofwaterless depends on whether the temperature of the environment is high (on asunnyday) or low on a cold day aswell as the amount of water vapour in the air (humidity).