Transpiration Lab Essay Example
Transpiration Lab Water is essential to plants in many ways. It first provides the major substance for living, to keep cells from shriveling up and dying. The second major function is to keep the plants rigidity. As plant cells become turgid, full of water, the cells expand, filling the extent of their cell walls, which are kept taught with turgor pressure. If the cells lose water, two problems occur.
First, the cells dehydrate, causing the organism to die. Second, turgor pressure is lost as cells become flaccid, limp and unfilled, causing a loss of support for the plants structure which makes it appear wilted. As aquatic plants evolved into large complex land plants, an adaptation occurred in the center of plants to allow full growth without the problem of water loss. Transpiration Lab Essay Example.A system of vascular bundles extending from the tips of the furthest leaves to the deepest roots of each plant developed, carrying water in xylem sap and sugar in phloem. While phloem can transport sugar in any direction within the plant, xylem can only move water up, from root to leaf. Once in the leaf, the water evaporates through stomatatiny gaps in the lower epidermis of each leaf, which are regulated by guard cellsa process called transpiration The movement of water into and out of the xylem involves water pressure factors in different sections of the plant.
As water slips into the roots through osmosis, a positive water pressure gently pushes the water into the plants roots and supplies a jumpstart for the waters journey up the vascular bundle. However, it is not this pressure that supplies a great force towards the upward movement of water; it is the evaporation of water from the stomata that pulls water upward and out. When the stomata are open to take in carbon dioxide for carbohydrate production, water begins to evaporate and seep out of the tiny holes in each leaf. With a constant pull of water outward, other water molecules are pulled up to replace it. The pull is provided by the cohesive properties of water molecules as each leaving molecule pulls on another molecule which is hydrogen bonded to it. The process continues as a series of movements until all the water molecules in the xylem sap are being pulled upward by their hydrogen bonds to the water molecules ahead of them. Thus the slight negative pressure occurs.
ORDER A PLAGIARISM-FREE PAPER NOW
Different environmental factors can have impacts on the intensity of water evaporation, and thus the rate of plant transpiration. Just like water in an open environment, a dry environment would increase the evaporation of water, and the rate of transpiration. A hot or very bright environment would do the likewise. Conversely, moist, dark, or cool environments would allow for a slower rate of transpiration because water would not be as readily evaporative. When testing the rate of transpiration for any given plant, I hypothesize that plants exposed to copious quantities of light will transpire more rapidly than those in a regular environment.
Methods We selected a bean plant on which to test varied environmental factors on transpiration. The different environments included excessive sunlighta floodlight one meter from the plant, wind/dry aira stationary fan approximately one meter away from the plant on low speed, humid/rainy climateleaves misted, then covered with a clear plastic bag (open at the bottom for air exchange). Normal room conditions were also tested for the control. One bean plant was used for each simulated environment. To set up the experiment, four pieces of Tygon clear plastic tubing were cut to sixteen inches.
Inside each was placed the tip of a 0.1-mL pipette. Taking four ring stands, one paired with each tube/pipette set, each end of the tubing was clamped, so that the tubing made a “U” shape. Transpiration Lab Essay Example. Next the tubing was filled with water so that no air bubbles were present and that water completely filled the tubing and pipette. The four bean plants were each placed into the open end of their respective tubing, then sealed with petroleum jelly around the sides (to prevent accidental water evaporation). The plants were allowed to sit for ten minutes before the initial reading was made, to allow for equilibration.
After recording levels of water for all plant environment simulations, readings were made in ten minute increments until thirty minutes elapsed. After this, the leaves were cut off of each plant to be weighed and measured. With these figures, we found the total surface area of each plant, after which we could calculate the rate of transpiration for each climate. Results To determine the rate of transpiration for each tested bean plant, the cumulative water loss (in milliliters) was divided by the leaf surface area of each plant (in meters squared). This rate was figured for each time increment: initial, ten minutes, twenty minutes, and thirty minutes.
Table 1 shows these calculations for the control, group a, floodlight, b, fan, c, and mist, d. The relationship among the data is shown on Figure 1. The lines for test plants b and c both show high rates for transpiration, while control plant a is at a moderate rate of transpiration and test plant d has a relatively low rate of transpiration compared to the other plants. Conclusion As Figure 1 shows, the plants tested in dryer climates, b and c, showed higher rates of transpiration. This is due to the greater potential for evaporation in their environments.
The extra exposure to light adds heat which dries up water vapor around the plant and inside the leaves, as it leaves through the stomata. The water in the tube was then pulled by the negative pressure created by the evaporation of water, increasing the transpiration rate.Transpiration Lab Essay Example. With plant c, the fan dried water vapor around the plant and in the leaves, causing the area to be dry, thus creating a negative pressure for water in this plant as well. Plant d had a very low rate of transpiration because its environment was very moist. Water was very unlikely to evaporate in the misted enclosure, therefore causing the plant only to need to replace the water which it used to maintain its turgor pressure.
The environment for plant a provided a normal room climate. Although evaporation was likely, it did not seem to be a large factor in the plants functions. So, as water did escape from the stomata of the plants leaves, the slow rate created enough negative pressure to replace the water being lost to the air and being used by the plant, which wasnt very much. When this experiment was initially done in our classroom, many faults occurred. Without prior experience handling plants and petroleum jelly, the experiment is difficult.
While it is a good idea to see the experiment in order to understand it, the book provided the best data.
When water is transported from the roots to the mesosphere cells in the leaves, it is evaporates out the stomata, called transpiration, to create a lower osmotic potential. Osmotic potential is the part of the water potential of a tissue that results from the presence of solute particles. Even though the stomata open to release water, it also brings in carbon dioxide to produce sugar and oxygen through a process of photosynthesis. The water absorbed by the roots is moved by osmosis, root pressure, adhesion, and cohesion from high to low areas of water potential.
From the roots, water is transported with osmosis with a pressure pulling the water and minerals up towards the leaves. It is the transpiration pull moving it up with the help of cohesion and adhesion. Transpiration decreases the water potential causing water to move in and pull upward into the leaves and other areas of low water potential.Transpiration Lab Essay Example. Loss of water through transpiration can be facilitated by the opening and closing of the stomata depending on environmental condition.
The rate of transpiration depends on several environmental factors such as light, humidity, temperature, ND air movement, while the rate of evaporation depends on the water potential gradient, which is contributed by gravity, pressure, and solute concentration. The purpose of this experiment is to measure pressure changes on the different types of environmental factors that affect the rate of transpiration. Hypothesis If the temperature of an environment increases, then the rate of transpiration in plants will increase and will reduce the surface area of leaves.
Materials This lab requires a Labiates, Fernier Gas Pressure Sensor, utility clamps, ring tan, a leaf with its stem, plastic tubing clamps, a pipette, a refrigerator, 300 millimeter beaker, plastic syringe, water, and graphing paper. Procedures First, connect the utility clamp on the ring stand with the Gas Pressure Sensor. Then, connect the plastic syringe to one end of the 36-42 centimeter plastic tube. Place the other end of the tube in a 300 millimeter beaker of water. Then, use the syringe to draw water up into the tube until it is full.
After that, connect the plastic tubing clamp on the tube. While bending the tube to make it into a U awards the sky, remove the syringe without spilling any water. Then, put the leaf with its stem in the opening of the tube with the end with the plastic tubing clamp. Carefully push the stem down of tube without spilling, and then squeeze the clamp shut. Then, connect the plastic tube to the Gas Pressure Sensor. There should be a mark on the tube at the starting water to remember for refill later on. Then, the Sensor should be connected to the Labiates.
Collect data for fifteen minutes for the pressure. Then, place the leaf onto graphing paper and trace it. Find the number of surface area. After that, place the leaf in a refrigerator. Clean up the materials and return the next day. Take the leaf out of the refrigerator and set up the equipment again. Connect in the Labiates, and then find the data of the pressure for fifteen minutes. Then, place the leaf onto graphing paper and trace it. After that, calculate the surface area of the refrigerated leaf. Remember to record down other classmates variables of their different environmental conditions.
Plants have adaptations to enable them to increase and decrease water lost including the shedding of leaves in colder temperatures, the peeing and closing of the stomata, thicker cuticles, and different shape of leaves depending on the environment. Transpiration Lab Essay Example. An advantage of closed stomata on a plant is that the plant loses water through the stomata; however to save the water it can close it. A disadvantage is that the open stomata takes in carbon dioxide for photosynthesis, but when it is closed it cannot take in carbon dioxide. The light and the fan decreased the water potential in the leaves and water moved up the stem by the transpiration pull.
ORDER A PLAGIARISM-FREE PAPER NOW
Conclusions During this experiment, it was found out that as temperature increases, the remonstration increased as well and as temperature decreases, the transpiration decreased as well. Therefore, this supports the hypothesis. For the class, it was found out that as sunlight increased, transpiration increased. As wind increased, transpiration increased. As humidity increased, however, transpiration decreased. These conditions led to the increased water potential gradient which causes the transpiration pull to be stronger. The control plant for all of these conditions should be the one with the most normal and stable environment.
In this experiment, there were a few experimental errors such as measurement errors and incorrect us of equipment. The sensor valve was connected to the plastic tubing too early, and therefore the lab had to be restarted. There were also some technical difficulties with the Labiates because the time length was set differently than the instructions. To improve this experiment, there should two experimental temperature conditions. One was the refrigerator and the other one should be beside a heater. This will allow one to see the difference temperature changes of hot, room temperature, and cold. Transpiration Lab Essay Example.