What is ‘Phototropism’? How does it occur in plants? Describe an activity to demonstrate phototropism

What is ‘Phototropism’? How does it occur in plants? Describe an activity to demonstrate phototropism.

Phototropism is defined as the growth movement of plants in response to light stimulus. You will note that in plants, bending of shoots towards light is called positive phototropism whereas, the bending of roots away from light is called negative, phototropism.

Activity: Take 2 seedlings of mustard plant. Keep them in a small bottle containing water. Now close bottle with a split cork, then keep it inside a wooden box that is provided with a small opening on one side. Now keep box near to a light source in such a way that “opening in box faces light source”.

Response of a plant to light: After 2-3 day, you will see that “shoots bend towards light, but roots bend away from light.” This type of growth movement in response to light stimulus is termed as “phototropism”.

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