Explanation

Long day plant require light period of 14-16 hours for subsequent flowering. This distinctive feature of long day plant is the long light period entirely prevents flowering but long nights interrupted by light, even briefly, cause the infinitive effect of the night to be lost and the plants flower, e.g., Hyocyamus niger (henbane), Spinacea (spinach), Beta vulgaris (sugarbeet), wheat, oat, radish, lettuce.