Record Details
Dynamic simulation model of transpiration process with stomatal control mechanism
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Dynamic simulation model of transpiration process with stomatal control mechanism |
| Names |
Woo, Kwang Bang
(creator) Stone, Louis N. (advisor) |
| Date Issued | 1964-12-11 (iso8601) |
| Note | Graduation date: 1965 |
| Abstract | Because the life processes of the plant are related in a complex way to the balance between the water demand of the atmosphere and the water availability to the plant root, an exploration of the dynamic status of water in the plant is very important. The stomata constitute the main regulating system on the leaf transpiration. At the present time, no integrated analysis of the dynamic system of the soil-plant-atmosphere continuum and the stomatal control mechanism of the plant is possible by means of classical soil physics and biophysics. As an approach to the integrated analysis, a simulation model of the transpiration process with the stomatal control mechanism is presented. Van den Honert suggested the use of Ohm's law describing water flow into, through, and out of plants. In the present study, this hypothesis is expanded to include an analogous storage factor to deal with the dynamic flow of water in the plant. A set of differential equations for water transport in the plant is expressed in terms of the water potential variable. The dynamic description of the water status in the plant is then completed by introducing the system gain which is a function of both the transpiration rate and the soil water condition. The present study on the photosynthetic process is mainly concerned with the diffusion and photochemical processes of the plant-CO₂ system. For the diffusion process of CO₂ through the leaf, two kinds of storage factors have been developed: (1) one for CO₂ reduction process and (2) one for CO₂ storage process. The photosynthetic process is related to the light response of the stomatal movement. The real mechanism of stomatal movement in leaves is still unknown. Many biologists are reviewing (1) a turgor mechanism and (2) the active water transfer theory in the guard cells as an explanation of stomatal movement. Based on their conclusions, a possible model of the stomatal control mechanism is proposed. Adaptive control theory is applied to the development of a model. The resultant model shows a balancing type of the control mechanism. The transfer functions of each part of the system are derived. The dynamic system gain of the transpiration process is realized by the similar type of the Corbin's method of a computer-controlled adaptive control system. The entire system is then simulated on an analog computer; its dynamic characteristics with consideration of various environmental effects are investigated. |
| Genre | Thesis/Dissertation |
| Topic | Plants -- Transpiration |
| Identifier | http://hdl.handle.net/1957/48272 |
