Development of nano-order monitoring system of plant and its environment using bio-speckles

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Purpose of the present research is to develop a highly sensitive measurement system to monitor the various conditions and activities of plant based on optical interferometric techniques using laser speckle, such as electronic speckle pattern interferometry (ESPI), statistical interferometry (SI), speckle difference method. The information concerned with the biological activities such as growth lies in the scattered light field from the surface of the plant. To obtain such information, we have applied SI and ESPI. Aiming to establish an optical method to monitor the influences of environmental conditions and environmental pollution on the plants, experiments were conducted using ozone as a representative substance of air pollution. The SI has achieved extremely high sensitivity to measure the expansion of object. Using SI, the growth speed of the leaves of plants could be successfully measured with the sensitivity of subnano meter scale and with very high temporal resolution of second s … More cale. It was clearly demonstrated that SI could detect the change of the plant growth for the 0.12 ppm ozone exposure, which is the density level to issue a photochemical oxidant warning in Japan. Since there was no method to observe the behavior of plant with such a high temporal resolution at nano menter scale so far, various interesting behaviors of plants were newly revealed through the present research project. One of new discoveries is that the growth speed of the plant is never constant but fluctuating all the time. It was found that the ratio of the standard deviations of fluctuation in growth speed of plant before and after the ozone exposure depends on the ozone density. This quantity may lead to a figure for the air pollution and its influence on the plants.ESPI has applied to observe the blooming process and geotoropism of the plants. The validity of the method to observe the adaptation of plant for the change of environmental conditions was experimentally confirmed.Those optical methods have also applied to observe the growth of plant roots. As experimental results, it was shown that SI is more appropriate for such a thin object as root and because of its high sensitivity. Less