Monitoring of the influence of environmental conditions on plant growth using statistical interferometry

In this study, we are developing optical methods to monitor the condition of plant, i.e., biological activity or growth, aiming to investigate the influence of the environmental conditions. The statistical interferometry developed by the authors has been applied to measure the growth of the plant. This method utilizes the statistical properties of a fully developed speckle field and has the advantage of simple optical system to achieve measurements with an extremely high accuracy. In the experiments to demonstrate the validity of the method, the growth speeds of the plants were measured under various environmental conditions of watering and light illumination. It has been clearly demonstrated that the statistical interferometry has a high sensitivity for monitoring the growth of the plant at a nanometer scale with a high temporal resolution of second scale.