Homework Assignment

The leaves of a plant are the main photosynthetic organs and are involved in gas exchange and water transportation throughout a plant (Evans et al, 17). A leaf typically consists of an upper and lower epidermis, the mesophyll cells, veins, guard cells and stomata. The mesophyll cells contains spongey cells which have large gaps between each cell to allow oxygen and carbon dioxide circulation. The mesophyll cells contain palisade cells, which are located beneath the upper epidermis. The palisade cells contain many chloroplasts, which are green organelles. Located in the internal layers of chloroplasts is the pigment chlorophyll which is involved in trapping the light energy in photosynthesis (Evans et al, 17).

6. Describe several adaptations that enable plants to reduce water loss from their leaves. Include both structural and physiological adaptations.

Introduction: Photosynthesis can be defined as a solar powered process that removes atmospheric carbon dioxide and transforms it into oxygen and carbohydrates (Harris-Haller 2014). Photosynthesis can be considered to be the most important biochemical process on Earth because it helps plants to grow its roots, leaves, and fruits, and plants serve as autotrophs which are crucial to the food chain on earth. Several factors determine the process of photosynthesis. Light is one these factors and is the main subject of this experiment. The intensity of light is a property of light that is important for photosynthesis to occur. Brighter light causes more light to touch the surface of the plant which increases the rate of photosynthesis (Speer 1997). This is why there is a tendency of higher rates of photosynthesis in climates with a lot of sunlight than areas that primarily do not get as much sunlight. Light wavelength is also a property of

12. Describe two ways (two different things you could measure) to estimate the rate of photosynthesis in a particular plant. What specific measurements would you need to make for each in order to estimate GROSS photosynthesis?

The purpose of this experiment was to investigate the effects of light intensity on the rate of photosynthesis in a Moneywort plant. By observing the plant in distilled water mixed with sodium bicarbonate, different light bulbs were targeted onto the plant. The measurement of the amount of bubbles present on the plant during the trial of the experiment enabled us to identify the comparisons between the activity of the light and the process of photosynthesis.

This type of reaction is an oxidation-reduction (or redox) reaction. This reaction is also [anabolic/catabolic] and [endergonic/exergonic].

Introduction: Metabolism is a term in which defines all of the chemical reactions involving energy production. Some of these chemical reactions involve cellular respiration “by which is the series of metabolic process by which living cells produce energy through the oxidation of organic

The rate value of the spinach leaves that were not given light was negative. The negative change in the amount of oxygen can be explained by the fact that, in cellular respiration, one of the reactants is oxygen.

Photosynthesis is a the process in which plants and other organisms to turn light into energy. To see if this is true I will test to see if spinach leaves discs can be effected by photosynthesis. I predicted that more disc would float in the light than in the dark. After writing down my hypothesis, I started the procedure. I cut up the spinach leaves into the disc and put cold water in the three petri dishes so the leaves would float in the water.

This experiment demonstrates the effects of pH on the rate of photosynthesis by examining the behavior of leaf disks in different pH solutions under light. In this experiment, we used five different pH levels: pH 5, pH 6, pH 7, pH 8 and pH 9. These solutions were created using a combination of hydrochloric acid and sodium hydroxide. Spinancia olcerea or spinach, leaves were used in the experiment to examine the effects of pH on the rate of photosynthesis. The rate of photosynthesis was measured by counting the number of leaf disks that rose to the surface of the solution after each minute. In acidic solutions, the rate of photosynthesis increased while in basic solutions, the rate of photosynthesis decreased.

Stomata closure is a coping strategy that plants use when there is low water available in the soil which prevents cavitation in the vessels of the xylem (Huber, 2015). It is also found that stomatal closure not only helps regulate transpiration in plants that have low water availability, but it also increases its water use efficiency (Huber, 2015). Wind is also considered to be a factor that affects transpiration in plants. Another study observed the effects of stomatal distribution (such as amphistomatous leaves) in leaves of a plant in low wind environments (Foster, 1986). The experiment found that amphistomatous leaves had the greatest transpiration rate at low wind speeds while hyperstomatous leaves had a higher transpiration rate than the hypostomatous leaves (Foster, 1986). Leaves contain what is called a boundary layer that can be defined as a still layer of fluid containing gasses and liquid that surround the leaf that affects the movement of CO2 and water in the leaves depending on its thickness (Bot 201L lab manual, 2016). In this study, the effects of wind will be observed on the transpiration rate and stomatal conductance in the leaves of

Elodea Canadensis, also referred to as American waterweed or common elodea, is an aquatic plant that is usually found in lakes, ponds or even rivers. Elodea helps support aquatic life such as young fish and amphibians by providing shelter and can be consumed as food by ducks and beavers. Elodea, like many other plants, relies upon photosynthesis to acquire its energy and to make food. To determine the importance of light energy in the process of photosynthesis, two Elodea plants were placed inside CO2 saturated water and exposed to different light intensities: one was under full light exposure while another was covered with mesh clothing to reduce the amount of light that it received; the solutions to this plants were then neutralized and compared to a control group which had no Elodea to see the amount of CO2 that each would have left after a period of an hour. The yielded results indicated that under high intensities of light, the Elodea plant photosynthesized and respired at the same rate; and while it was covered, it photosynthesized more because of an indicative decrease in CO2 levels. Therefore light energy is an essential aspect that affects the amount of CO2 that a plant can use in the process of photosynthesis.

We know that light is an important part of both terrestrial and aquatic ecosystems. In a forest system both the canopy and the understory absorb light. The type of forest and leaf cover present determines the amount of light that reaches the understory. This can be measured using the LAI (Leaf Area Index), which is the amount of leaves per unit ground area. Light quantity in forests is affected by several factors such as tree species, age, and density.

Our lab investigated the morphological characteristics of leaves found in the sun and shade on various species of maple and oak trees around campus. Our null hypothesis was Acer and Quercus acclimate similarly with regards to SLW (specific leaf weight), size, and sinuosity. Our hypothesis was Quercus acclimation is greater than Acer SLW, size, and sinuosity. We tested these hypotheses by picking small sections of a branches from both maple and oak trees. A group was assigned either a maple or an oak tree, and needed a total of three different trees per group. Once three different trees were chosen, groups needed three shade leaves and three sun leaves of off each different tree. In total, each group should then end up with 18 leaves for testing. After collecting the leaves, we ran them through the LiCor 3100 leaf area meter to identify the area of each leaf. Major results found by the classes’ mutual data was each one of our p-values were greater than .05. This means that we failed to reject the null hypothesis. Thus, the lab results do not support our hypothesis that Quercus acclimation is greater than Acer SLW, size, and sinuosity.

Plant cells normally contain a large amount of water which is liable to freeze at low temperatures, with grave risk of damage to the protoplasm. Tropical plants are very easily killed by freezing, but it is evident that plants of temperate and arctic regions must have become adapted to survive the period of winter frost, meaning that they have developed cold resistance.