Plant show variable response related to developmental, physiological and growth. They respond to a particular wavelength of light. A plant shows directional growth in response to light. In general, shoot moves towards the light and roots move away from it. Plants actively show a response to light maybe to specific wavelengths which allow them to adjust and adapt to their surrounding environment and optimize growth. For example, some type of seeds only grows and germinate when they receive light. There are some plants which grow in the shade of neighbouring plants, they can increase their growth rate to get more sunlight. This shows that plants have an ability to detect or sense light. Special molecules called photoreceptor help the plant in sensing light. The photoreceptor is made up of a special protein which h are linked to chromophore (light absorbing pigment. Phototropism is of two type: negative phototropism and positive phototropism. Shoots which grow towards light show positive phototropism while roots growing away from light show negative phototropism.
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