Plants actively show a response to light maybe to specific wavelengths which allows them to adjust and adapt to their surrounding environment and accelerate their growth. Plants have the ability to sense or detect light. Special molecules called photoreceptors help the plant in sensing light. The photoreceptors are made up of a special protein which is linked to chromophore ( light absorbing pigment). The main photoreceptor is phototropin.
To observe phototropism, perform the following simple experiment.
Take two small potted plants. Place one plant near the window and the in the other one cover the base of the plant tightly and hang the part upside down. Observe the plant for 1-2 weeks. You will observe that the plant placed near the window bends towards in the direction of incoming light. The growth of plant parts towards light is called as positive phototropism. Whereas in the other plant you will observe that even after placing the roots in light, it grows away from the light showing negative phototropism.
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