photoperiodism is a flowering response of plants caused by fluctuation in day length and season
– depend on minimum light requirement of plants
– short day, long day or day neutral plants
– it’s controlled by phytochrome system
– it’s non-directional in response
phototropism is a response of plants/plant parts to direction of light
– shoots bends toward light source
needed for photosynthetic parts to intercept maximum available light
– it’s controlled by differential auxin concentration.