Plants are amazing gifts from nature! They give us food, clothes, and even materials for our homes. They are super important because they help keep our world healthy. Just like all living things, plants have special life processes, such as breathing, growing, getting rid of waste, and making new plants. In this article, we will learn about how plants make seeds, focusing on a special part called fertilization.
Plants have a cool way of making new plants, which involves three main steps: pollination, fertilization, and germination. We have talked about pollination and germination before, so now let’s dive into fertilization.
Fertilization is a way plants reproduce, where the male part from pollen joins with the female part (ovum) to create a zygote. This zygote grows into seeds.
Flowers are like the plant’s special organs for making seeds. During pollination, pollen moves to the female part of the flower and enters the ovary. Here, the pollen tube opens into the ovule, allowing the male nucleus to meet the egg’s nucleus, forming a zygote.
To understand fertilization better, let’s look at pollen. Pollen grains are usually yellow and powdery, with two layers:
The embryo sac, or ovary, has three antipodal cells attached to the chalaza. It also has two polar nuclei in the center and three cells near the micropyle (a tiny opening). The biggest cell is the egg cell, with two smaller cells called synergids next to it.
When pollen lands on the stigma, the pollen tube grows and connects to the micropyle of the embryo sac. The generative cell splits into two male parts, which travel down the pollen tube. One male part joins with the egg to make a zygote, and the other joins with the two polar nuclei to form a triploid endosperm nucleus. This endosperm becomes food for the growing embryo.
This special process, called double fertilization, happens in all flowering plants at least once. After fertilization, the ovary turns into fruit, which is why seeds are inside fruits.
The process of fertilization in plants was first discovered by Ralph B. Strasburger in 1884. If you look at seeds, you might see the micropyle as a tiny pore, a reminder of this amazing process.
Fertilization is a key step in the life of plants, leading to seeds and new plants. Understanding this process helps us appreciate nature and shows how complex plant reproduction is. We hope you enjoyed learning about how seeds are formed!
Seed Exploration Activity: Collect different types of seeds from fruits you eat at home, like apples, oranges, or tomatoes. Observe the seeds closely and draw them in your notebook. Can you spot any differences in size, shape, or color? Discuss with your family or friends why you think these differences exist and how they might help the plant grow in different environments.
Flower Dissection: With the help of an adult, carefully pick a flower from your garden or a nearby park. Gently take it apart to see the different parts inside. Can you find the stigma, style, and ovary? Try to locate the pollen grains and the ovule. Draw a diagram of the flower and label its parts. Discuss how each part helps in the process of fertilization.
Pollination Role Play: Pretend to be a bee or a butterfly and act out the process of pollination. Use a small brush or cotton swab to transfer “pollen” (you can use colored powder or flour) from one flower to another. Talk about how pollinators help plants reproduce and why they are important for our environment. Think about what might happen if there were no pollinators.
