Everybody knows that flowering plants usually grow from seeds, but have you ever wondered where the seeds come from? Seeds are made when pollen from the male part of a flower reaches the ovule from the female part of a flower.
It seems simple enough, but there are actually several different ways that plants can reproduce! In this article you will to learn about some of the methods of plant reproduction, as well as some of the advantages and disadvantages of these different modes of reproduction. There are many reasons why it is important for scientists to study plant reproduction. For example, plants are very important for the foods you, your family, your friends, your teachers, and even your pets eat.
We can eat plants directly, like fruits and vegetables. We need plants for our other foods too, like the grass that cows eat to give us milk, cheese, and yogurt. By learning about the plants that we need for food, scientists can figure out how we can grow more of these plants, how to grow them more efficiently, and how to use less of valuable resources such as land and water, in the cultivation of these foods. Other than food, can you think of more ways that we use plants?
Self-fertilizing plants, known as selfers , make pollen that can fertilize their own ovules Figure 1A. If a flower has both female and male parts, it is called hermaphroditic.
Sometimes there are separate female and male flowers, but they are on the same plant. Monoecious plants are examples of selfers because they do not need two separate plants in order to reproduce.
How many of the selfers pictured in Figure 2 do you know? Cross-fertilizing plants, known as outcrossers , need two separate plants in order to reproduce. Sometimes, a flower can have both pollen and ovules, but they cannot fertilize each other; this is called self-incompatibility. For outcrossers to successfully reproduce, the pollen and ovules need to be from separate plants.
In other cases, the two sexes are completely separate, with some plants making only male flowers and other plants making only female flowers. This is similar to how reproduction works in most animals. The pollen from the male plants needs to travel to the ovules of the female plant in order to produce seeds.
How many of the outcrossers pictured in Figure 2 do you know? There are still a lot of mysteries about how and why some types of outcrossers are dioecious. Scientists decided to look at the DNA from many different kinds of dioecious plants to try to understand what makes them male or female.
There is a lot you can learn from DNA that may not be so obvious from just looking at or growing a plant. A DNA sequence is a lot like letters on a keyboard: the letters by themselves do not mean anything, but when they are put together they can form words.
Scientists compared the genes from several dioecious plants to figure out which genes were important in determining whether a plant is male or female. They discovered that there are several ways a plant can determine gender. For example, there can be genes in the DNA that make plants male or genes that prevent them from becoming female [ 1 ].
Looking at plant DNA is not the only way scientists can learn about the differences between male and female plants. For example, they can study the shape differences between male flowers and female flowers.
You can do this too! Unlike humans, plants cannot move around. This means that plants need to use other strategies to move pollen to ovules to make seeds. For outcrossers, the male plants do not need to spend their energy making seeds, so they can spend more energy on making and dispersing high-quality pollen.
Similarly, since female plants do not need to make pollen, they can spend more energy on making high-quality ovules. This means that they can pass on more resources to their offspring to improve their chances of survival. Furthermore, because dioecious plants need two different plants to reproduce, the offspring will have more variety in the genes they get from the parents. This is especially important if the environment changes, because the offspring with greater variety in their genes will be more likely to have genes that help them adapt to a new environment.
Male cones make pollen, which is carried to female cones by the wind. After the female gametes are fertilised by male gametes from the pollen, the female cones produce seeds, which are then scattered away from the plant by wind or animals. Most gymnosperms are trees. There are about 20 native gymnosperms in New Zealand, including our tallest tree, the kahikatea Dacrycarpus dacrydioides , white pine.
Ferns, mosses, liverworts and green algae are all plants that have spores. Spore plants have a different life cycle. A parent plant sends out tiny spores containing special sets of chromosomes. These spores do not contain an embryo or food stores. Fertilisation of the spores takes place away from the parent, usually in a damp place. An embryo is formed and a new plant grows from it. For more information, view the Fern life cycle interactive. New Zealand has about species of ferns and over species of moss.
Classification helps us put order into the world around us. Scientists start with very big categories like plants and animals and continue to divide the groups based on shared characteristics — like methods of reproduction. Take a bag of thawed frozen broad beans to school and hand a few to each student.
Students can remove the seed coat and split the bean to reveal the embryo inside. Use magnifying glasses to examine the embryos. Add to collection. Nature of science Classification helps us put order into the world around us.
Activity idea Take a bag of thawed frozen broad beans to school and hand a few to each student. Go to full glossary Add 0 items to collection. Download 0 items. Twitter Pinterest Facebook Instagram. Email Us.
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