Mimosa pudica: modelling of mechanical stimulation of plant movements

• Main Author: Neo, De Sheng
• Other Authors: Li Hua
• Format: Final Year Project
• Language: English
• Published: 2016
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/67939
• Institution: Nanyang Technological University

Seismonastic and nyctinastic movements are the two main movements exhibit by Mimosa pudica in response to external stimulation and circadian clock respectively. Both movements activate osmoregulation in the pulvinus. There will be exchanging of water, potassium ions and chlorine ions between the extensor and flexor. There will be a sudden loss of turgor in the cells causing the leaves to close and the petiole will start to bend downwards within a few seconds. The processes are reserved in the recovery phase. Past studies had been focusing on the different possible type of mechanisms behind those movements. Hence, the objectives of this project looks to extend the studies to determine the effect of the dimension of the different parts of the plant and relate the discoveries to real world application, if possible. A total of nine variables are plotted against the closing time, the opening time and the bending angle of Mimosa pudica. The variables are number of stimulation, diameter of the stem, the pulvinus, the petiole, length and width of the leaflet, temperature, humidity and force applied on the leaflet. One of the key findings is that Mimosa pudica has the symptom of fatigue after an average of ten stimulation. This was indicated by the steep increased in the recovery time after ten stimulation. This mimicked the muscles soreness experienced by human beings after numerous repetition of weightlifting. Future studies can look into reducing the recovery time in Mimosa pudica and hence, relate to human beings and bring a breakthrough to athletics’ performance.