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. Phototropism is of two types: positive phototropism & negative phototropism. Shoots and all those plant parts which grow above the ground show positive phototropism as the shoot grows towards the light and bends in the process. Roots on the other hand show geotropism which means growth against the light. It is called negative phototropism. Therefore, even after hanging the base portion of the plant upside down, the roots will grow against the direction of light. It will show geotropism always.
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