Plant Draft 5

In addition to red light, they tested the effects of blue light on the plants. Blue light is received by phototropins in plants. Phototropins are in control of stomatal opening and chloroplast movement. When the rice stems were exposed to the blue light, it had a dosage dependent pattern. At a low fluence rate of blue light, the rice stems had similar root growth and angle to rice stems that were grown in the dark. In comparison, at a high fluence rate of blue light, the rice stems had similar root growth and angle to stems that were grown in white light. The direction of rice roots growth in response to white light was found to be reversible. They studied four different rice plants in different setups; one plant was exposed to white light and ethylene for four days, and it grew roots that went downwards. The next plant was grown in darkness, and its roots grew upwards.