Angiosperm Reproduction, Germination and Development
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| Sexual and Asexual Reproduction |
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| Strawberry plant: What evidence so you see that either sexual and/or asexual reproduction has occurred? | Stawberry stolen: Is this evidence of asexual or
sexual reproduction? |
| Flower Structure |
| Gladiolus Flowers |
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| Gladiolus flower
Is this flower perfect or imperfect? How many stamens are found in this flower? |
Close-up of Gladiolus floral parts
Point to the structure in which the males gametophyte develops. |
Stigma of Gladiolus
What is the purpose of the stigma? Where is the style in this photo? |
Close-up of stigma tip in Gladiolus
Why is the stigma tip moist and sticky? |
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| Longitudinal section of Gladiolus ovary
What will the small white structures develop into? Is the male gametophyte or the female gametophyte produced in these structures? How do the sperm get from the stigma tip to the egg in the ovule? |
Cross section of Gladiolus ovary
Is this a monocot or a dicot flower? Point to the ovules, ovary, carpels, and locules. The ovarian wall will develop into what structure when mature? |
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| Dicot Flowers |
Can you think of a reason why these flowers are so highly colored?
| Daffodil Flowers |
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| Is this flower perfect or imperfect?
Is this a monocot plant or a dicot plant? |
Is this an example of a complete or an incomplete flower? | What are the globular, whitish structures in this photo?
Will they develop into fruits or seeds? |
| Tulip Flowers |
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| Is this flower perfect or imperfect?
Is this flower a monocot or a dicot? |
Are the anthers in this photo mature or immature?
How many cells are in a mature pollen grain? |
| Oat Flowers |
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| Do grasses produce flowers?
Why aren't these flowers of grasses colorful and odorous? |
Point to the stigmas and anthers in the above photo of an oat flower.
Where would the ovary be located? How does cross pollination occur in grasses? Why are grass flowers not highly colored? |
| Wheat Flowers |
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| Point to the anthers in the above photo. |
Diagram and name the floral parts of a monocot flower such as a gladiola.
In order for a flower to be considered complete what must be present?
What determines if a flower is considered incomplete?
Define a perfect flower in botanical terms.
Most grasses have flowers arranged in clusters. What term is used to describe this flower arrangement?
Is the pistil (stamen) sporophyte or gametophyte tissue?
| Gametogenesis in Flowering Plants |
| Pollen Formation |
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Cross section of an anther |
What is the name of the flower structure that pollen development takes place in? |
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What are the red structures in the cells? How many pollen grains will be produced by each of these cells? What genetic recombination event is happening here? Are these cells from the sporophyte or gametophyte generation? |
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Tetrads of pollen grains Are these cells haploid or diploid? |
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| Is this a mature anther or a developing anther ? | What do you think these structures are? What key features did you use to identify them? | Germinating pollen grain.
On what structure does the pollen grain nomally rest as it develops a pollen tube? Is this pollen tube a sporophyte or gametophyte? How many sperms will be transferred by one pollen tube? What are you looking at here? |
In flowering plants the female (male) gametophyte is what?
Microsporangia are the male or female reproductive organs?
Megasporangia are the male or female reproductive organs?
In a mature pollen grain, two nuclei are produced by mitosis. What are they called and what do they produce
Egg Formation
| How many carpels does this flower have?
Point to the ovules. What happens in the ovules that is significant to plant reproduction? |
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How many carpels do you see? |
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Point to the megaspore mother cell in the above photos. Does it first divide by mitosis or meiosis? |
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| Embryo Development |
Are these photos of monocot or dicot embryos?
Point to the cotyledons and radical in these photos. Where is the seed
coat?
What does the seed coat develop from?
What is the function of the cotyledons?
| Seeds |
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Seeds (corn or lima bean)
- Are most of the nutrients for the young plant stored in the cotyledons or the endosperm of this specimen?
- What is the name of this area?
- What is the majority of these composed of? (substance that turned dark when we placed dye on the seeds in lab)
- What will the structure indicated by the pointer develp into?
- What is the object in the seed?
- Is this a monocot or dicot seed?
Where is the hilum?
Indicate where the integuments are located and what they develop into?
Why are many seeds good to eat?
| Fruits |
Possible fruit questions
How many carpels does this fruit have? What do ovules develop into in the fruit? What is the name of this layer? Why do many types of fruit contain seeds with very hard seed coats? What is the structure indicated by the pointer? What does the structure indicated by the pointer develop from? Are all fruits edible? What does the flesh of an edible fruit develop from? A seed is a mature __________ and a fruit is a mature ____________?
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| Investigating the Effects of Hormones on Plant Development |
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| Rosette Mutants |
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Compare the major features of monocot and dicot flowers
How is sexual reproduction in flowering plants adapted to the terrestrial environment?
How are gametophytes formed, gametes produced in flowering plants?
Describe the difference between pollination and fertilization?
Outline the steps in endosperm development.
Describe embryonic development in a dicot seed.
Why do seeds have lots of starch and oil? Why do we eat seeds like wheat, corns, nuts?
A seed has been described as a mature ovule. How can this be true? Explain.
Why are flower petals colored? Are all flowers colorful?
What could prevent self fertilization and genetic inbreeding in perfect flowers (Fig. 38.5 and 38.6 in the Campbell text)?
How might hybridization between species be prevented (pollinator specificity)?
How do flowering plants protect gametes and embryos?
Describe how fruits are adaptations to promote seed dispersal. For example, why are some fruits sweet and colorful?
Make a list of several foods commnly called vegetables that are actually fruits.
The pistil is described as the female part of a plant and the stamens as the male. Criticize this statement by describibg where sperm and eggs are actually produced.
What advantage is it to the plant to undergo asexual reproduction?
What is the principle advantage of sexual reproduction?
True or False: Pollenation and fertilization are the same. Explain your answer
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Credits
Photos by Maria Oehler and Warren Dolphin
Layout by Warren Dolphin and Mark A. Mangum