Question

Why time is important in measuring the rate of transpiration of plant​

Answer 1

Transpiration is a process that involves loss of water vapour through the stomata of plants. Transpiration is thought to be a 'necessary cost or evil' to allow the plant to absorb water from the soil. It is an inevitable process. ... Transpiration helps maintain the turgidity in plants.

Answer 2

so you don't lose track of the rate of the transpiration. they change over time.