Colorado Agriscience Curriculum
Section: Plant Reproduction
Unit 4: Plant Reproduction
Lesson Number 1: Introduction to Plant Reproduction
Colorado Agricultural Education Standards:
AS 11/12.4 The student will demonstrate an understanding of physiological processes in agriculturally important plants
HRT 11/12.2 The learner will understand and describe the anatomy of horticulture plants.
Colorado Science Standards:
SCI 1.1 Asking questions and stating hypotheses, using prior scientific knowledge to help guide their development
SCI 3.1 Students know and understand the characteristics of living things, the diversity of life, and how living things interact with each other and with the environment.
SCI 3.3.5 Using examples to explain the relationship of structure and function in organisms.
SCI 3.3.6 Describing the pattern and process of reproduction and development in several organisms.
Student Learning Objectives (Enablers)
As a result of this lesson, the student will …
Objective 1: Define Propagation, Sexual Reproduction, & Asexual Reproduction
Objective 2: List and explain the different types of flowers & Seeds.
Objective 3: Define pollination, fertilization and germination.
Time: Instruction time for this lesson: 55 minutes + lab (This lesson ends with a lab that could be done in the first half of the next class period. Lesson number two in this unit begins with a lab which can be done the second half of day 2. Lesson 1 & 2 should take approximately three days with one day beginning used for the two labs.
Tools, Equipment, and Supplies
Projector with power point or color overheads
Corn and bean seed (Classroom application)
Dissection Kit (Classroom application)
Key Terms.
Propagation Sexual Reproduction Asexual Reproduction
Monocots Dicots Sepals
Petal Stamens Pistil
Stigma Style Ovary
Pollination Fertilization Germination
Interest Approach
Begin by discussing the production of seed corn.
Who can tell me how seed corn is produced?
Elicit responses and facilitate a class discussion.
Seed corn is produced by utilizing two different verities of field corn. The first verity is planted in rows of four and is called the “cow” row. The second verity is planted on each side of the four cow rows and is called the “bull” row. The corn plants are grown as any other crop of corn until the plants begin to tassel. When the cow rows begin to tassel a machine or crew must go through the field and remove all of the tassels from the cow rows. Why is this?
Class discussion.
Very good, the tassels are removed from the cow rows so that they can not pollinate them selves. The tassels are left on the bull rows so that as they mature they will pollinate the cow rows. This creates a cross breed of corn or what is known as a hybrid. When the seed corn is harvested the bull rows are not used as seed corn, why? Very good, they are not hybrids sense they pollinated themselves. Let’s take this new found knowledge and further explore the fascinating field of plant reproduction and genetics.
Summary of Content and Teaching Strategies
Objective 1. Define Propagation, Sexual Reproduction, & Asexual Reproduction
Slides 1 – 4
Slide 2: Discuss what the meaning of the word propagation is. It is simply to multiply and to insure the continuation of the species. In agriculture do we want random propagation or controlled? For agriculture purposes we are propagating plants to preserve or enhance there genetic contributions to the desired crop. Discuss what is involved in both sexual and asexual reproduction, through discussion see how much information the class, as a whole, can develop about these two forms of propagation.
Slide 3: Sexual reproduction results in the production of genetically unique plant. How is this done? What are the different methods of pollination? Why in alfalfa seed production must honey bees be used for this purpose? Alfalfa is a plant that is incapable of self pollination. Honey bees are used for the purpose of pollination with the fringe benefit of honey production. Sexual reproduction in plants results in the formation of an embryo which occurs when pollen and the ovum are united. Sexual reproduction results in the formation of a genetically unique individual with contributions from both parents.
Slide 4: Does asexual reproduction occur in plants in nature? Very good, it does. Do any of you know what species of plants propagate asexually in nature? Good, examples are strawberries, Canadian thistle, bind weed, and morning glory. What is another name for asexual reproduction? Excellent, asexual propagation is synonymous with plant cloning. It is simply the production of a new plant where pollen and ovum where not united. It occurs in nature and in the agricultural industry as well. Asexual reproduction can be done with parts of leaves, stems, and roots of the parent plant. Asexual reproduction results in the formation of a new plant that is genetically identical, or a clone, to the parent plant. In the case of Canadian thistle whole colonies may be clones of each other because female and male reproductive anatomy occurs on different plants.
Objective 2. Reexamine and explain the different types of flowers & Seeds.
Slides 5- 9
Slide 5: Who can remember what the two classifications of seeds are? Very good, the two types are called monocots and dicots. Which classification are generally broad leaf plants? Good, dicots are generally broad leaf plants and monocots are from the grass family.
Slide 6: Monocots are seeds with one seed leaf or cotyledon. Thus the name “mono” meaning one and “cot” referring to the cotyledon. Monocots seeds are solid, their leaves have parallel venation, and their roots are fibrous and advantageous. Examples of monocots are corn, wheat, oats, and barely.
Slide 7: Dicots are the second classification of seeds. Dicots are plants with two seed leaves or two cotyledons. Their veins are webbed and their leaves are broad instead of the blades of monocots. Examples of dicots are beans, potatoes, sugar beets, and sunflowers.
Slide 8: Who can tell me what the two types of flowers are? Very good, the two types of flowers are Perfect and Imperfect Flowers. These are sometimes called Complete Flowers and Incomplete Flowers.
Slide 9: The diagram is an example of a perfect or complete flower. An incomplete flower is missing one or more of the labeled parts.
Objective 3. Define pollination, fertilization and germination.
Slides 10- 11
Slide 10: Who can tell me what pollination is? Great job, pollination is the transfer of pollen from the anther to the stigma of a flower of the same species. This can be accomplished by a variety of means including wind, gravity, bees, or manual pollination.
Slide 11: If pollination is the transfer of pollen from the anther to the stigma what is fertilization. Great job, fertilization is the union of the pollen and ovum. Once the ovum is fertilized a chemical reaction occurs forming a hard lining around the seed to prevent any further pollen from uniting with the ovum. Germination is the sprouting of the seed. It is essentially seedling growth and development. The germination stage is over when the plant is capable of photosynthesis.
Review/Summary.
We have reviewed a lot of material today. We have established that plant propagation can be accomplished sexually or asexually. Sexual propagation involves the union of pollen and ovum and results in a genetically unique plant. Asexual propagation occurs both manually and in nature. It is the formation of a new, genetically identical plant from part of a leaf, stem, or root of the parent plant.
The two classifications of seeds are monocot and dicot. Dicots have two cotyledons and are broadleaf plants while monocots have one cotyledon and are from the grass family. The two types of flowers are perfect and imperfect which are also called complete and incomplete flowers. Pollination is the transfer of pollen from the anther the stigma of a plant while fertilization is the union of pollen and ovum. Finally, germination is the periods of time of seedling growth before the plant can perform photosynthesis. Are there any question?
.
Application
Extended classroom activity:
Acquire examples of monocot and dicot seeds such as corn and beans. Soak them overnight and have the class dissect the seeds to identify the different anatomy of each type of seed. Upon completion of this lab have the students perform a lab write up.
FFA activity:
Life Knowledge lesson: HS 28 Objectives 1 & 2: Just as each plant plays a specific role in the universe, so does each person. It is important for students to realize that their unique talents and abilities are important to the success of their own society or community.
SAE activity:
Research career opportunities in the fields of seed production. Have students create a report on five careers in this field.
Unit 4, Lesson 1 2