Effective teaching of water relations in plant cells could include such didactic methods as “questioning the author,” which allow teachers to monitor students'. Plant–water relations concern how plants controlthe hydration of their cells, including the collection of water from the soil, its transport within the plant and its loss. WATER RELATIONS OF PLANT CELLS 1. BERNARD S. MEYER. The Ohio State University. Few topics in the field of plant physiology have been so obscured.
Teaching about Water Relations in Plant Cells: An Uneasy Struggle
Evaporation of water from leaves is primarily controlled by stomata, and if not made good by the flow of water from soil through the plant to the leaves, results in the plants wilting. Resistances to this flow are still not well understood. Plants perform best when they are turgid, that is when the water within their cells has a positive hydrostatic pressure.
The flows of water through plant and soil are driven by gradients in hydrostatic pressure over macroscopic distances, by differences in water potential across semipermeable membranes or by diffusion as water vapour from the leaves to the atmosphere.
Resistance to these flows, and the factors influencing them, vary markedly as the transpiration stream moves from soil, across the roots, longitudinally in the xylem and eventually through the tissue of the leaves to the evaporating surfaces within the leaf. Surface tension generates an upward pull on the water in the capillary tube. Instruments used to measure hydrostatic pressure of soil water. The porous ceramic cup allows water to move between the soil and the inside of the instrument.
Eventually the pressures equalize and the pressure gauge of the instrument then gives the pressure in the soil water. Enough gas pressure is applied to the chamber to bring the water in the soil to atmospheric pressure, when it is on the verge of exuding from the outlet. The open questions were generally applied to obtain in-depth, qualitative data concerning student understanding of osmosis and plasmolysis.
The closed and semiopen questions were applied to obtain quantitative data about the stage of education at which the concepts had been taught and the educational methods that had been used to introduce students to them. The content validity of the questionnaire was established by two experienced biology academics. Next, the pilot study was completed by 32 biology students at Adam Mickiewicz University, and the initial version of the questionnaire was revised.
For example, some of the open questions were clarified by changing them to semiopen or closed items. The final version of questionnaire consisted of 12 questions or tasksof which four were closed, two semiopen, and the other six open see questionnaire in the Supplemental Material.
Plant Cell Water Relations | Jaja Amuenda - raznomir.info
Four of the questions identified the education level at which students became familiar with the concepts of diffusion, osmosis, and plasmolysis and the didactic methods used to teach them. Students were asked to label their questionnaires with the numbers of their student groups and the last four digits of their personal identity numbers according to the scheme G group number and PIN last four numbers e. Participants All the participants were students enrolled in the plant physiology course in The research was carried out in two stages.
First, the diagnostic questionnaire was completed by a group of second-year biology students before starting a course on plant physiology comprising lectures and practical exercises in the field of water relations in plant cells stage 1. Second, the same group of students answered the diagnostic questionnaire after the teaching sequence stage 2.
The size of the participant group at this stage was Structure of Plant Physiology Course The whole plant physiology course comprised 30 hours of lectures, 10 hours of seminars, and 60 hours of practical exercises. The concepts of diffusion, osmosis, and plasmolysis were discussed directly during a lecture and 9 hours of practical exercises two sessions of 4.
During every practical exercise, students in groups of four performed four or five experiments. For each experiment, the students were obliged to write a report containing their results and conclusions. The conclusions were discussed with the teacher and, if necessary, corrected.
One week after the practical exercises, the diagnostic questionnaire for stage 2 was completed. Questionnaire Analysis The questionnaire analysis method was based on Creswell First, the data were organized and prepared for analysis. We then read through all the questionnaires and letter-coded the data; the letter-coded data were used to develop categories for details, see answer key in the Supplemental Material.
The data were interpreted and described on the basis of the created categories. We applied the constant comparison technique when coding the data Glaser and Strauss, In this process, codes and categories were repeatedly refined.