Mimosa Pudica : experiment of light stimulation of plant movements

The Mimosa Pudica is an interesting and unique plant which is often found all around Singapore. It has been known for its ability to close up upon being stimulated. The purpose of this study is to determine the reactions of the Mimosa Pudica under light stimulation. Lights from different parts of th...

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Bibliographic Details
Main Author: Cheong, Collin ZhiWei
Other Authors: Li Hua
Format: Final Year Project
Language:English
Published: 2018
Subjects:
Online Access:http://hdl.handle.net/10356/75125
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Institution: Nanyang Technological University
Language: English
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Summary:The Mimosa Pudica is an interesting and unique plant which is often found all around Singapore. It has been known for its ability to close up upon being stimulated. The purpose of this study is to determine the reactions of the Mimosa Pudica under light stimulation. Lights from different parts of the visible light spectrum were used in conducting this experiment to observe the relationship between the intensity of light and the wavelength of light with respect to the fatigue time and closing time of the Mimosa Pudica. Plants were placed in a cardboard box and the leaves were allowed to naturally close up to expand their energy from photosynthesis. A single light source is provided through a hole on the top of the box. The leaves were allowed to naturally open up under the exposure to the light source. The plants were monitored through a phone placed on the other hole on the box. Once the leaves were fully opened, the time taken was recorded using an online multi stopwatch website. The plants were then mechanically stimulated, prompting them to close up and the process was repeated until transition to the fatigue phase was reached. After which the experiment was repeated using different coloured light and intensity. The results showed that the Mimosa Pudica is reactive to both blue and white light while being unreactive to green, red and yellow light. Initial data showed that the fatigue transition cycle for white light was longer as compared to blue light. Further analysis on blue light stimulation at high intensity revealed that the fatigue transitioning phase ranged from the 2nd cycle to the 5th cycle. Plants also demonstrated positive response to UV light stimulation, with the response being similar to blue light stimulation. The author recommends the use of a more precise measuring instrument such as red light interferometer to improve the accuracy of the experiment. Effects of different types of UV light can also be studied.