Unit A Lesson 9: Plant Reproduction
Completion requirements
Unit A Lesson 9: Plant Reproduction |
Learning Targets |
Inquiry Question: How do plants reproduce?
Plants reproduce sexually, passing on their traits to their offspring.
Plants reproduce sexually, passing on their traits to their offspring.
At the end of this inquiry, you should be able to answer the following questions:
- How is sexual reproduction different in plants than it is in animals?
- What are the female and male parts of the plant?
- What are the differences in cross-pollination, self-pollination and cross-fertilization?
Page 33 in your textbook will help you answer these questions about plant reproduction.
Introduction
Plants Reproduce Sexually
As in animals, sexual reproduction in plants requires the joining of a male gamete with a female gamete to produce a zygote and then developing into an embryo. The main difference is that some plant species produce both male and female gametes. Other plants produce only female gametes or male gametes, which is similar to animals and humans.
The Parts of a Flower
Understanding the parts of a flower is very important to understanding how fertilization in plants occurs. Consider Figure 2.11 on page 33. Note the female and male parts of the flower. The pistil is the female part consisting of the stigma, style, and ovary. The stamen is the male part consisting of the anther and filament. The ovary contains the ovule , which contains the female gametes, and the anther contains pollen , which contains the male gametes.
Figure 1 - The structure of a flower.
To help you remember which is the male and female parts, note the word stamen. The 'men' in stamen will help you remember that the stamen has the male parts of the flower.
Watch
The videos "Sexual Reproduction in Flowering Plants" and "Parts of a Flower and Pollination" review the parts of the flower. Study carefully the female and male parts as well as the female and male gametes.
Watch the video "Parts of a Flower and Pollination".
Cross-pollination
Cross-pollination requires a male gamete from one flowering plant and a female gamete from another. Recall that the male gamete is contained within the pollen
and the female gamete is contained within the ovule
. The pollen is located on the male part of the plant (the stamen), and the ovules are located in the female part of the plant (the pistil). How do plants reproduce with pollen and ovules?
Bees and other insects are essential to the pollination process. As they search for the sweet nectar (from which bees make honey, for example) they land on the anther of one flower and get pollen on themselves. Then, they fly to another flower looking for more sweet nectar and the pollen might be dropped on the stigma of that second flower. The pollen follows a pollen tube down the style until it reaches the ovary that contains the ovule. This is where fertilization occurs. We could say that pollination is the result of insects getting their feet dirty!
Bees and other insects are essential to the pollination process. As they search for the sweet nectar (from which bees make honey, for example) they land on the anther of one flower and get pollen on themselves. Then, they fly to another flower looking for more sweet nectar and the pollen might be dropped on the stigma of that second flower. The pollen follows a pollen tube down the style until it reaches the ovary that contains the ovule. This is where fertilization occurs. We could say that pollination is the result of insects getting their feet dirty!
Watch
Watch "Flower Reproduction" to learn more about cross-pollination and cross-fertilization in plants.
Watch the video "Introduction to Pollination" for more good pollination information.
Self-Pollination
Note that flowering plants can self-pollinate because they are technically both male and female, but to keep variation in the species, the plants prefer to cross-pollinate with other plants. This is nature’s way of preserving biodiversity. With the union of male and female gamates, fertilization occurs and the zygote develops as a seed. The seed produces the new flowering plant.
Note that flowering plants can self-pollinate because they are technically both male and female, but to keep variation in the species, the plants prefer to cross-pollinate with other plants. This is nature’s way of preserving biodiversity. With the union of male and female gamates, fertilization occurs and the zygote develops as a seed. The seed produces the new flowering plant.
Watch
Watch the video "Self Pollination" for an example of what this term means.
Interactive
Watch this video titled "Sexual Reproduction in Flowering Plants". Note that the female part of the flower according to your textbook is the pistil, but in this video, it is called the carpel. These names are interchangeable, but you are expected to know
the pistil as the female part.