Visualization of the Osmotic Pressure Concept Through Plasmolysis Observation in Rhoeo discolor: A Physiological Study for Science Education

Abstract Plasmolysis is a physiological phenomenon that occurs in certain plant tissues, particularly the epidermis, driven by the process of osmosis. However, osmotic pressure often remains an abstract concept in science education, necessitating a concrete visualization. This study aims to explain the morphological changes in the epidermal cells of Rhoeo discolor before and after plasmolysis, and to analyze the causative factors of this phenomenon. A qualitative descriptive method was employed in this experiment. The epidermal tissues were observed under a microscope at 4x and 10x magnifications. Two treatments were applied: water as a neutral medium and a NaCl solution as a hypertonic medium. The results showed that when exposed to water, the epidermal cells appeared tightly packed with a deep purple color, indicating that no plasmolysis occurred. Conversely, exposure to the NaCl solution caused the cells to become loosely arranged and the deep purple color to fade to pale, confirming the occurrence of plasmolysis. This condition is caused by the hypertonic nature of the salt solution, which draws water out of the cells, causing them to shrink. It can be concluded that the distinct color and structural changes in Rhoeo discolor make it an excellent and highly accessible biological model for visualizing osmotic pressure, thereby enhancing conceptual understanding in science education.