The objective of this study was to detect the plant stoma response under the lighting conditions of continuous and 1 to 15 minutes of lighting. In this study, a real-time measurement system was developed to observe a living plant stoma continuously for a long period in a growth chamber, using a microscope and a color TV camera. A video recording system was adopted to obtain details of stoma movement, and images were captured every 30 seconds. From the experimental results, it was observed that the stoma opened slowly 5 minutes after the lights were turned on, and then opened rapidly until it reached the maximum pore size. In guard cells, light stimulus activates a proton pump, the resulting hyperpolarization of the plasma membrane opens voltage-sensitive K⁺ channels, and then the water entering the guard cells opens the stoma after the K⁺ ions have entered. This process may cause 5 minutes of delay, and delay was also observed after the light was turned off. Ten minutes of lighting opened the stoma to the maximum size, as well as 5 minutes of lighting with a 30-minute interval. For better utilization of lighting, these on/off controls were suggested to give a 14% production benefit with 8.3% more energy input.