Useful link: http://www.bio.miami.edu/dana/226/226F09_4.html

Purpose:

This Plant ACTIVITY is part 2 of a series of activities designed to enhance your understanding of cells, cell theory, genetics, evolution, anatomy, organs, organ systems, classification, biochemistry and ecology.

Objectives:

To observe the anatomy of a plant.To research the function of the anatomy of a plantTo compare and contrast the anatomy of a plant with that of a human and other organisms.To apply this knowledge and create a unique model of life on Earth.

DAY 1 OF PLANTS

Seed Dissection Lab

PurposeThe purpose of the lab is to dissect a bean seed in order to identify all of the parts of an embryonic plant (including the cotyledons, radicle, epicotyl, hypocotyl, and seed coat.Background Information:1. There are two kinds of seed-bearing plants: the flowering plants are called “angiosperms”, and the non-flowering plants are called “gymnosperms”. Most seed plants are the flowering kind. There are over 250,000 species of flowering plants, and only about 600 non-flowering plants. Corn and beans are angiosperm seeds.2. A seed is a tiny life-support package. Seeds generally have three parts: a tough covering (seed coat), an embryonic plant consisting of the plumule (embryonic leaves), epicotyl (upper stem), hypocotyl (stem of adult plant), and radicle (roots) , and a food supply (cotyledon). The hilum is the site of attachment to the ovary. In beans, the hilum is a dent in the side of the seed.3. The outer covering of the seed is called the seed coat. The seed coat helps protect the inside of the seed from insects, disease, and damage. Sometimes the seed coat is smooth and paper-thin like that of a pinto bean. A coconut’s seed coat, however, is rough, thick, and hard. A seed cannot develop into a plant until the seed coat is broken.4. The embryo is the tiny plant inside the seed. The embryo gives rise to the root, stem and leaf structures.5. Surrounding the embryo is the food supply. The food supply is the seed’s only source of nourishment as it pushes up through the soil and grows into a young plant. When the food supply is gone, a green plant begins to manufacture its own food through photosynthesis. The food supply for a bean is used up in about two weeks.6. Various environmental conditions trigger germination, including moisture level, light level, and

temperature. When these conditions are met, the seed germinates.7. Germination is the process through which the embryo inside the seed begins to grow. As the seed germinates, it develops roots, a stem, and then leaves. If a seed is not allowed to germinate within a certain length of time, the embryo inside the seed dies. Each plant species has a specific amount of time that a seed can survive before it uses up all of its stored food. The food supply is very important to the seed as it germinates. A bean seed without its food supply grows poorly, if at all. A seed with half of its food supply grows better, but a seed with both halves does the best of all. Seeds from some species of plants need to sprout within two weeks while others can wait as long as two thousand years. Some seeds need to undergo certain conditions, like the cold of winter or, even a forest fire, in order to sprout while others germinate as soon as they fall from the parent plant. Seeds germinate at different rates depending on how much food they have stored.Pre-Lab Questions1. Why were the seeds soaked in water overnight, prior to beginning the dissection?2. What is the purpose of the cotyledon?3. Where does the plant get its food once the seed has germinated?4. What adult plant parts will each of the embryonic parts become?5. Is the seed you are dissecting a monocot or a dicot? How can you tell?Materials:1 Lima Bean, dried and 1 Lima Bean that has been soaked for 24 hours to softenforceps, Paper towels, Dissecting Microscope, blade, dissecting trayProcedure1. Answer the pre-lab questions prior to beginning your dissection.2. Place the seed on a dissecting tray. Using the forceps, carefully tease the seed coat away. Then, gently separate the cotyledons.3. Illustrate (DRAW) what you see on your data sheet.4. Use the dissecting microscope to more closely observe the seed. Illustrate the enlarged bean showing the embryonic plant.5. Label the illustration at the bottom of the page using the terms provided.

Draw and label the following

External seed Split seed Split seed under a dissecting microscope

Label the parts of the following diagram. Be sure to use these terms: hilum, seed coat, plumule, epicotyl, hypocotyl, radicle, cotyledon.

Conclusion

1. What was the purpose of the experiment?

2. What were the major findings? (data)

3. Identify the structures of a seed, their function, and state the organ system they belong in.

4. Compare and contrast the seed structures and organ systems of a plant with the comparable human structure and organ systems LAB REPORT FORMATA. Cover pageTitleyour nameblockdateB. Purpose AND objectiveC. All you know about plants listD. Pre-lab questionsE. MaterialsF. ProcedureG. DataH. Conclusion

Clean upBegin to choose which seed you would like to plant on Day 2Assist with soaking the seeds

DAY 2 OF PLANTS - Create Plant Data Sheet, Review Video to plant seed, Plant seed

Set up an initial Data Sheet and include the following information:Title: Plant Data SheetPlant name ________________Number of days to Germination ___________Number of days to bloom _______________Plant height ______________Plant spacing ____________Conditions it Grows best _____________ (full sun, partial sun etc)DRAW YOUR SEED

Create a chart with the following information:

Day Date Time Growth (Y/N) Description (Ht.,# leaves etc)

LABEL YOUR CUPPlace your cup in the tray for your block (name of plant, block, your name)

How to Plant a Seed: Video

Day 3 of Plants: Flower Dissection

Sexual Reproduction in Flowering PlantsFlower Anatomy detail

Introduction

The angiosperms are seed-bearing plants that produce flowers. The seeds, which contain the plant embryo, are produced in the flower. All the parts of a flower are actually modified leaves that are specialized for their roles in the reproductive process. Flower parts are arranged in circles called whorls. They are attached at the enlarged base of the flower, the receptacle.

Flower structures can be divided into two groups: the essential organs and the accessory organs. The essential organs are the reproductive structures, which include the stamens (male) and the pistils (female). The accessory organs are the sepals and petals, which surround and protect the essential organs.

The stamen is the male reproductive organ and consists of two parts: the anther and the filament. The anther is the enlarged structure at the top of the stamen. Inside the anther are pollen sacs. Special cells within the pollen sacs undergo meiosis to form pollen grains. Each pollen grain contains two sperm nuclei. When the pollen grains mature, the pollen sacs split open to release the dust-like pollen. The filament is a thin stalk that supports the anther.

The pistil is the female reproductive organ and consists of three parts: the stigma, style, and ovary. The stigma is an enlarged portion at the top of the pistil that becomes moist and sticky when mature. The style is the middle portion of the pistil. It can be long and slender, short, or even absent, depending upon the species. The ovary is the enlarged structure at the bottom of the pistil. The ovary contains one or more hollow compartments called locules. Each locule contains one or more ovules. Special cells within the ovule undergo meiosis to form ova (eggs) containing egg nuclei.

Pollination occurs when pollen grains land on the sticky surface of the stigma and are trapped there. The pollen grain germinates and a pollen tube emerges from the grain. It releases special enzymes that digest a cell the wall on the surface of the stigma. The pollen tube grows down through the style to the ovary and enters the ovule, making a continuous passageway for the two sperm nuclei to enter the ovum. Fertilization occurs when the sperm nuclei join the egg nuclei. The fertilized egg becomes an embryo. The wall of the ovule thickens and forms a seed, thus enclosing and protecting the embryo. The ovary wall also thickens and develops into a fruit. In some plants such as apples, the ovary walls become fleshy and contain stored sugars and starches. In other plants such as walnuts, the ovary walls become dry and hard.

Use the Flower Observation Chart below to complete the procedure

flower_observation_chart.xls

Download File

Purpose

To study the structure of a typical flower.To study the male and female reproductive organs needed for sexual reproduction in flowering plants.

Materials

fresh flower(s), dissecting microscope, plain paper, clear tape,forceps, scissors, metric ruler, razor blade

Procedure

1. Record your data on the Observations Chart accessible.

2. Obtain a single flower and observe its parts carefully. Flower parts are arranged in a circular pattern. Each circle is called a whorl. The whorls are attached at the enlarged receptacle located at the base of the flower. Please read this overview before you begin your flower dissection: As you examine your flower, you will be carefully removing parts beginning with the outer whorl and working your way in towards the pistil. You will arrange each whorl in a circle on the plain paper, beginning with the sepals asthe largest outermost circle. As you proceed with your dissection, you will carefully tape each whorl of flower parts into position and label them (please use pencil!). As each whorl is observed and removed, you will complete the appropriate information in the Observations column of the chart. Use theinformation in the handout to complete the Function column of the chart.

3. The sepals form the outermost whorl of the flower. The sepals are leaf-like structures that are usually green in color. Sometimes, the sepals are the same color as the petals, or appear to be another set of petals of a different color. The function of the sepals is to protect the inner part of the flowerbefore it blossoms. Gently remove the sepals, tape them into position onto the paper, and label them. On the chart, record the following observations:

a) How many sepals does your flower have?

b) Describe the appearance of the sepals (color, markings, etc.).

4. The petals are found directly under the sepals. The color and odor of the petals help to attract birds and insects to the flower for pollination. Gently remove the petals, tape them into position onto the paper, and label them. On the chart, record the following observations:

a) How many petals does your flower have?

b) Describe the appearance of the petals (color, markings, etc.).

5. The stalk-like structures inside the petals are the stamens, the male reproductive organs. Depending

on the species, the stamens may be attached to the receptacle, to the petals, or to the pistil. The enlarged portion at the top of the stamen is the anther. Inside the anther are pollen sacs,which produce pollen grains. When the pollen grains mature, the pollensacs split open, releasing the dust like pollen grains. The filament is the thinstructure that supports the anther. Gently remove the stamens, tape theminto position onto the paper, and label them. On the chart, record the following observations:

a) How many stamens does your flower have?

b) To which structure(s) were the filaments attached?

c) Have the pollen sacs opened? How can you tell?

d) If pollen grains are visible, describe their appearance.

6. The central structure of the flower is the female reproductive organ, the pistil. The top of the pistil is the stigma. When mature the stigma is enlarged, and its surface is moist and sticky. The style is the middle portion of the pistil. It supports the sigma. Some flowers lack a style. The ovary is the enlargedstructure at the bottom of the pistil. The ovary contains one or more hollow compartments known as locules. The locules contain ovules, which in turn, contain the egg nuclei. Carefully remove the pistil by cutting it from the stem just under the ovary. Using pencil, make a life-sized sketch of the entire pistil (just the outline) in the center of the plain paper and label it. Cut the style just at the top of the ovary, tape it next to your sketch, and label the stigma and style. Using the ruler, measure the length of the style in millimeters. Cut a thin cross-wise section of the ovary and tape it under the stigma and style. Label the ovary wall, locules and ovules. Using the dissecting needle, carefully pick the ovules out of one of the locules. Try to estimate how many ovules are contained in one locule. On the chart, record the following observations:

a) What color is the pistil?

b) Describe the appearance of the stigma. Is the stigma mature? How can you tell?

c) How long is the style (in mm)?

d) Describe the appearance of the ovary.

e) How many locules does the ovary contain?

f) Approximately how many ovules are contained in one locule?

7. Check your flower parts sheet and your chart for the following:

· All flower parts are correctly taped in place.

· All flower parts are labeled correctly (in pencil).

· The pistil is drawn on the paper (in pencil).

· Your name(s) and class period are written on the paper.

· The Observations column of your chart is completed.

Discussion - Please write the answers to the following questions in your lab databook using complete sentences.

1. Which does your flower produce in greater numbers: ovules or pollen grains? Explain why this would be important in terms of reproductive success.

2. What are some adaptations of flower petals to help attract pollinators?

3. How is the stigma of your flower adapted to capture and hold pollen?

4. Describe where pollination and fertilization occur.

5. Explain the differences between pollination and fertilization.

6. a) In which part of the male reproductive organ are the pollen grainsmade?b) In which part of the female reproductive organ are the egg cells made? c) By which nuclear process are these gametes formed?

7. How do the sperm nuclei in a pollen grain reach the egg nucleus in anovule?

8. a) Which part of the flower becomes the seed? b) Which part becomes the fruit?c) Which part of the fruit contains the embryo?

Conclusion

Check your chart to be sure that the function column is complete. Then summarize the information presented in this lab by creating a brief outline and writing it in your lab report. Your outline should

include information about types of flower parts, male and female structures, pollination, fertilization, and development of seed and fruit. Use the Introduction as your guide!