Mimosa Pudica : experiment for response of Mimosa Pudica subject to environmental stimuli

• Main Author: Chong, Yi Yang
• Other Authors: Li Hua
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/78322
• Institution: Nanyang Technological University

Mimosa Pudica - very common types of plants that can be found everywhere in Singapore. It is also known as the sensitive plant because of its unusually way of behaving. Its leaves will fold, and the stems will droop when been touched. These behaviours allow the plants to avoid from its predator by making the plants look smaller and with the sharp spines on its stems. Experiment was carried to give a better understanding of Mimosa Pudica mechanical stimulation. “Gravity”, are one of the experiment focuses and which is new set of experiment that are not done by any student working on Mimosa Pudica in the past. Experiment was carry on by controlling the force applies on the plants using bare hand, follow by placing the plant in horizontal and vertical position to meet the ‘gravity’ effect and to do result comparison. Hydrostatic pressure (also called turgor pressure), an important part to plant. Pressure keep the plants upright by exerting pressure on the cell wall, a rigid stem and leaf expanded out for sunlight and water is need for photosynthesis. This means that without water, plants cell will collapse and wilts and well-water plant is turgid, keeping the plant upright. Result shows that time require to close are shorten at night then on day time, reason being is that on night time the leave is already on the closing position and this process might take up to about less than a second to close before the complete stop of petiole. While vertical and horizontal position show a similar result that heavy force apply on plants will give faster closing time. Result also shows that during night time, time require is shorter compare to the day, this may due to the starting closing position is different from the day. Horizontal position shows faster closing time than vertical position. Which therefore conclude that gravity do play a part in the closing time, not just the turgor pressure. Vertical and horizontal data concluded that light and heavy touch did not cause or give extra help to the plants petiole angle movement. Although, it did not give any help by tapping on plants either on night and day. However, day and night result shows that during night-time, the amount of angle bend will be much more lesser than on day-time. Lastly, it was concluded that mimosa pudica angle movement are not cause by its plants size, either the plants diameter or length increases or decrease, it did not give an increase or decrease in plant movement but a constant uneven movement.