Effect of Light Illumination on Leaves Movement of Mimosa pudica

Abstract

A study on the effect of light illumination introduced to the leaves of Mimosa pudica was carried out using different light intensities. The leaves will open gradually from the closed condition after the light was illuminated. Plant of M. pudica was placed in the dark box during measurement meanwhile the Petiole (part of the stem) of the plant was at normal position (hanging up). The camera was fixed to the box to monitor the leaves’ movement continuous and real time. By using this method the change of the top view area of the leaves could be observed. A crossed line was drawn on the image recorded and was measured its length. The calculation of the length gives the percentage of leaves at open during the observation time. Ultrasonic apparatus was also used to monitor the change of leaves. From the results, at an illumination intensity of 200 Lux, the percentage of leaves to open completely with respects to the observation time was found to increase nonlinearly by taking the time of 25 minutes. For intensities of 400 Lux, the trend of curve was also similar but increase rapidly. The ultrasonic signals show much stable at 200 Lux comparing to 400 Lux that was fluctuating. That may be due to the relatively faster movement of the leaves to open. This natural phenomenon is interesting and may introduce any change of natural indication that could be explored for further applications.