state the importance placing the potted plants in a dark room for 24 hours prior to experiment on photosynthesis.write main events of photosynthesis
Answers
Plants are required to be kept in dark room prior to the experiment to carry out the process of destarching.
Before starting any experiment of photosynthesis, it is important to remove all the starch from the plants to make sure that the starch tested later is formed during the course of the experiment only.
Hence, when a plant is kept in dark before the experiment, it is unable to perform photosynthesis and derives its energy solely from the leftover starch in the plants.
Photosynthesis can be broadly divided into two phases: Light phase and the dark phase.
The main steps of photosynthesis are given below:
1.Absorption- light energy is absorbed by the chlorophyll present in stomata of leaves.
2. Conversion- Light energy gets converted to chemical energy bringing about production of hydrogen and oxygen from water molecules.
3. Reduction- Carbon-dioxide absorbed by the plants gets converted/reduced to carbohydrate molecules.
Solution: For carrying the starch test on the plants, it is important to place the potted plants in a dark room for 24 hours.
The plant is particularly placed in the dark room to destarch it. When the plant is placed in the dark room, photosynthesis does not take place due to absence of light.
The stored starch is removed or used up in the course of time.