Light irradiation can cause photosynthesis in plants. Green plants can undergo photosynthesis under sunlight. Photosynthesis mainly relies on blue and red purple light, and light can also emit red and blue purple light, which is absorbed by plants for photosynthesis. Scientific research has found that plants mainly rely on blue-green and red orange light for photosynthesis, which are contained in lighting.

Therefore, plants can also engage in photosynthesis under lighting. Green plants can undergo photosynthesis under the illumination of night lights, but the intensity of the light must reach a certain level. When plants are above the light saturation point, photosynthesis increases correspondingly with the increase of light intensity; When reaching the light saturation point, photosynthesis decreases with the weakening of light intensity; When the intensity is reduced to a certain level, the CO2 absorbed by photosynthesis and the CO2 released by respiration are in a balanced state; The light intensity at this point is called the light compensation point, and the plant can no longer engage in photosynthesis.

So, to be precise, photosynthesis can occur when the light intensity under illumination is above the light compensation point of the green plant, and cannot occur when it is below the light compensation point of the plant.