What can you see under the scope?
The dissecting scope is used to observe 3-D specimens under different magnifications. The specimens can be viewed at 7x magnification or as high as 50x magnification. Both specimens were found in front of Jenkins Hall on the Armstrong State University Campus. The bud in particular when viewed under the scope showed a different texture than shown with the naked eye an almost satin look to the petal with white hair like structures coming off. The leaf off the Loblolly Bay tree showed a significant color difference from the top and underside of the leaf.
- Edited by Evan and Chris
- Edited by Evan and Chris
Plant Cells and Scientific Drawings
This lab is designed to practice skills and techniques needed for upcoming labs and likely in any scientific field of study. These skills included creating and viewing a wet mount slide under a compound scope, recognizing different slide preparation techniques, identifying visible features of plant cells, using stains to bring out certain features of plant cells, and creating scientific diagrams.
Scientific Drawings
Epidermis of Allium cepa or the onion
This video is of a whole mount section from the epidermis of Allium cepa, or onion. The slide was stained with toluidine blue and viewed at 400x. The video shows cytoplasmic streaming within the vacuoles of the cells. Before adding the stain all you could noticeably see were the vacuoles of the cell, however after the stain was added you could clearly see the vacuole, cell wall, nucleus, and the cytoplasmic steaming within the cell. -Video and summary by Evan
Leaf Cells of Elodea canadensis (Canadian Pondweed)
This is a completely unedited video of the first photo above: a Elodea canadensis leaf cell at 400X total magnification with no stain and before a 5% CaCl solution was added. It also has all the same noticeable structures as the photo. Since the pictures do not do it justice, this unedited video was included because it shows the natural cytoplasmic streaming within a living Elodea canadensis leaf cell. The cytoplasmic steaming is plainly apparent due to the orderly movement of the relatively large, green chloroplasts within the cells.
Overall this was my favorite specimen of the day because I had the opportunity to experience many of the fundamental topics (streaming, osmosis, etc.) discussed in this lecture and prior lectures.
-Caption and video taken by Chris
-Video uploaded by Evan
Overall this was my favorite specimen of the day because I had the opportunity to experience many of the fundamental topics (streaming, osmosis, etc.) discussed in this lecture and prior lectures.
-Caption and video taken by Chris
-Video uploaded by Evan
Bell Pepper Sections
The bell peppers are a good example to see the transition a plastid can perform. The red pepper shows the plastid as a chromoplast, yellow pepper as a chromoplast, and lastly the green pepper as a chloroplast. When viewed under the compound microscope the red pepper had larger and a greater number of chromoplast. One unique thing I noticed was that in the green pepper the chloroplasts were in greater number in the cells near the outer skin of the fruit. -Photos and summary by Evan
Stem cross-section of Tradescantia (Spiderwort)
Section of Solanum tuberosum otherwise known as the potato
The photo to the left is of a section of a potato, Solanum tuberosum. The amyloplasts are stained with iodine which in the presence of starch show up purple. -by Evan
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Section of Unripe and Ripe Parenchyma of the Musa Fruit (Banana)
Photosynthesis: Pigments, Starch, and CO2
This lab was designed to better understand the process of photosynthesis. The first goal of the lab was to separate and identify the various pigments within photosynthetic tissue and understand why having multiple pigments is beneficial to a plant. The second goal of the lab was to observe how carbon fixation, that occurs during synthesis reactions, and how it is dependent on the products of the photo reactions. The third and final goal of this lab was to use a starch test and observe the effect of carbon-starvation on the starch reserves created from the synthesis reactions of photosynthesis. -By Evan
Plant Pigments
With the under-surface side down, we crushed Magnolia grandiflora leaf cells onto the chromatography paper using a glass stirring rod. This released the pigments within the photosynthetic tissue onto the paper, allowing them to be effected by the solvent mixture of petroleum ether and methylene chloride (2:1 mixture). These are the developing solvents for the chromatogram, which is the final product (the dried chromatography paper, after the pigments have been separated) that will then be divided and put into the spectrophotometer (a machine that measures the absorbency of each pigment, in a specific solution, and then prints out the absorbency of light at each wavelength on a graph.) -Photo by Evan -Caption by Evan and Chris
Light Absorption of Chromatography of Four Pigments
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CO2 Consumption in Photosynthesis with Elodea
Starch Test Using Coleus (Plectranthus scutellarioides) Leaf
Next Steps...
The starch experiment was my favorite and most interesting because it showed how the plant changes and prepares/effected for different conditions within its environment. -Evan
Simple and Complex Tissues
The goal of this lab was to be able to compare and contrast the different types of cells and tissues of the ground tissue system. These cells include parenchyma, collenchyma, and sclerenchyma. After the lab is completed you should be able to recognize the three tissue systems within a plant body. This lab will also show you how to identify water conducting cells within the vascular tissue system and be able to describe their structural features and function. Lastly, the lab will demonstrate the characteristics of the epidermis layer of plants.
Parenchyma and Collenchyma Cells (Ground Tissues)
Sections of Celery
Sclerenchyma Cells (Ground Tissues) in Different Species
Sclerenchyma of Pear fruit
Avocado Fruit
This is a picture of a tissue scraping from the peel of a section of an avocado, Persea americana. The cells were stained with Phloroglucinol-HCl and viewed at 400x. The stain showed brachysclereids or stone cells within the tissue and stained red. They are stained red due to Phloroglucinol-HCl staining lignin within the cell walls red. -Photo and Caption by Evan
Sclerenchyma Fibers of Snake Plant: Cross-Section
Sclerenchyma Fibers of Snake Plant: Longitudinal-Section
Dermal Tissues
Upper and Lower Dermal Tissues of the Inch Plant
The epidermis peel were my favorite cells to view because it showed the vast difference the cells take in each layer of tissue to perform the functions necessary for the plant to survive. -Evan
Vascular Tissues
Longitudinal-Section of Coleus (Plectranthus scutellarioides)
Tracheary Elements, Sclerids, and Parenchyma Tissue in Hoya
Cross-Sections of a Wax plant stem
Genetically Modified Organism Investigation: Part 1
This lab was used to determine and understand the growing trend of genetically modified organisms in agriculture today. The goals of this lab were to be able to explain what a genetically modified organism is, how to extract DNA from a plant food product, know why and how a polymerase chain reaction amplifies a target DNA sequence, and lastly understand some of the implications that genetic engineering of agriculture crops in reference to biodiveristy, ecosystems, co-evolution of plants and their pests, human health, and economics. -by Evan and Chris
The test food we chose for genetic modification were girl scout cookies called do-si-dos. We predict that the cookies will be genetically modified. -by Evan
The cellular contents we are releasing from the ground-up sample contain enzymes (DNases) that can degrade the DNA we are are attempting to extract. The InstaGene matrix is made of negatively charged microscopic beads that "chelate" or grab metal ions out of solution. It chelates metal ions such as Mg2+, which is required as a cofactor in enzymatic reactions. When the DNA is released from the sample in the presence of the InstaGene matrix, the charged beads grab the Mg2+ and make it unavailable to the enzymes that would degrade the DNA we are trying to extract. This allows us to extract DNA without degradation. Boiling the samples destroys these enzymes. -By Chris
PCR has three steps, a denaturing step, an annealing step, and an elongation step. During thermal cycling, the denaturing step of PCR, the DNA template is heated to 94 degrees Celsius to separate (or denature) the double-stranded DNA molecule into two single strands. The DNA is then cooled to 59 degrees Celsius to allow the primers to locate and anneal (bind) to the DNA. Because the primers are so much shorter than the template DNA, they will anneal much more quickly than the long template DNA strands at his temperature. The final step is to increase the temperature of the PCR reaction to 72 degrees Celsius, which is the optimal temperature for the DNA polymerase to function. In this step the DNA polymerase adds nucleotides one at a time at the 3' end of the primer to create a complementary copy of the original DNA template. These three steps form one cycle of PCR. A complete PCR amplification undergoes multiple cycles of PCR, in this case 40 cycles. -By Chris
The results of this experiment will be obtained next week after the PCR is completed and gel electrophoresis is performed.
Genetically Modified Organisms: Part 2
The purpose of this lab was to determine results on wether our test food was genetically modified by using gel electrophoresis. The goals of the lab were to be able to explain the process and interpret the results of gel electrophoresis using the PCR samples from last week. Understand why positive and negative controls were neccesary to validate the results. The last goal of the lab was to discuss the implications of GMOs on the environment, biodiversity, co-evolution of plants and their pests, human health, and economics. -By Evan
Gel electrophoresis uses electrical current to move different weighted DNA extractions through a gel. The different sized sample, or amount of base pairs, move through the gel at different speed and are measured by a comparison of the molecular weight ruler which moves at a known rate. The DNA moves through the gel because of the charge created by the device. DNA has an overall negative charge this means that the negative charged DNA will be pulled down toward the positive node. Under a UV light the gels will show bands, which are the different sized DNA that have moved through the gel. -By Evan and Chris
Results of Gel Electrophoresis
Our test food was do-si-dos, a girl scout cookie. The results show that in lane four our PCR product with a GMO primer did have a band at the 200 base pair line. The fact that the sample indicated the GMO primer means that do-si-dos tested positive for genetically modified DNA sequences (i.e. the have genetically modified DNA). The other samples were needed as controls and to test for any contamination of the PCR product.
If we were to repeat this procedure we would use a different known GMO sample since the results show something went wrong and we have multiple bands in lane six we would also repeat the experiment and use multiple samples to verify out results. - By Evan and Chris
- Lane one held a sample with a non-GMO food with plant primers. This is a positive control to test for the presence of plant DNA in the non-GMO organism.
- Lane two held a sample with a non-GMO food with GMO primers. This is a negative control to indicate that the non-GMO does not contain genetically modified DNA as well as to check for any contamination, either from the grinding of the non-GMO sample or from pipetting the different mixes into the PCR.
- Lane three held a sample of our test food with plant primers. This indicates weather or not we have successfully extracted plant DNA from our food sample, verifying the quality of the DNA.
- Lane four held a sample of our test food with GMO primers. This is to test whether our food was genetically modified or not.
- Lane five held a sample of a known GMO with plant primers. This is a positive control to indicate whether or not the plant primer is working.
- Lane six held a sample of a known GMO sample with GMO primers. This positive control indicates whether or not the GMO primer is working.
- Lane seven is holds the molecular weight ruler which is used as a reference to determine our product bands' sizes.
If we were to repeat this procedure we would use a different known GMO sample since the results show something went wrong and we have multiple bands in lane six we would also repeat the experiment and use multiple samples to verify out results. - By Evan and Chris
Bryophytes (non-vascular plants) and
Ferns (seed-free vascular plants)
Non-Vascular Plants: The Mosses
Moss Spores (Polytrichum sp.)
Living Moss Protonema (Phylum: Bryophyta)
Haircap Moss (Polytrichum sp.) Gametophytes with Sporophytes Attached
Peat Moss (Sphagnum sp.) Gametophyte Tissue
Stained with Phloroglucinol-HCl
Non-Vascular Plants: The Liverworts
(Phylum: Hepaticophyta)
Liverwort (Marchantia sp.) Thallus (Gametophyte)
Seed-Free Vascular Plants
Fern Sporophytes
(Phlebodium sp. - Family: Polypodiaceae)
Holly Fern (Cyrtomium falcatum) Frond with Sori
Fern (Psilotum) Stem Cross-Section
Stained with Phloroglucinol-HCl
Other Fern Sporophytes (Phylum: Monilophyta)
C-Fern (Phylum: Monilophyta) Observations
C-Fern Gametophytes in Culture Plates
C-Fern Sperm
The Seed Plants: Gymnosperms and Angiosperms
This week we studied and observed the seed plants, angiosperms and gymnosperms. The goals of this weeks lab were to recognize gymnosperms and angiosperms, understand their life cycle, and recognize the gametophyte and sporophyte generations. Other goals were to identify parts of flowers and understand their function, understand terms relating to ovary position, floral organs, and floral symmetry. The last goal was to prepare diagrams and record important features revealed during a floral dissection. -By Evan
The Cones
Ginkophyta
Coniferaphyta
The long needle pine showed an excellent example of how a plant adapted to decrease its chance for self-fertilization. This tree develops its female cones toward the top of the tree, while the male cones develop toward the bottom this prevents pollen falling from above onto female cones below. -By Evan
Flower Dissections
The flower dissection was my favorite part of this lab. It was interesting to see the many ways to describe a flower since before this I did not ever really think about flowers in those terms. -by Evan