DK Science: Seed Plants
Most plants grow from seeds. These seed plants fall into two groups, angiosperms and gymnosperms. Angiosperms are the flowering plants. Their seeds develop inside a female reproductive part of the flower, called the ovary, which usually ripens into a protective FRUIT. Gymnosperms (conifers, Ginkgo, and cycads) do not have flowers or ovaries. Their seeds mature inside cones. Seeds may be carried away from the parent plant by wind, water, or animals.
Dandelion seeds have feathery parachutes to help them fly far from their parent plant. A dandelion flower is actually made up of many small flowers, called florets. Each develops a single fruit. The fruits form inside the closed-up seed head, after the yellow petals have withered away. When the weather is dry, the seed head opens, revealing a ball of parachutes. The slightest breeze lifts the parachutes into the air.
INSIDE A SEED
A seed is the first stage in the life cycle of a plant. Protected inside the tough seed coat, or testa, is the baby plant, called an embryo. Food, which fuels germination and growth, is either packed around the embryo or stored in special seed leaves, called cotyledons.
SPREADING WITHOUT SEEDS
Seeds are not the only means of reproduction. Some plants create offshoots of themselves – in the form of bulbs, tubers, corms, or rhizomes – that can grow into new plants. This type of reproduction is called vegetative reproduction. As only one parent plant is needed, the offspring is a clone of its parent.
A bulb is an underground bud with swollen leaf bases. Its food store allows flowers and leaves to grow quickly. New bulbs develop around the old one.
A tuber is a swollen stem or root with buds on its surface. When conditions are right, the tuber’s food store allows the buds to grow.
A corm is a swollen underground stem that provides energy for a growing bud. After the food in the old corm is used up, a new corm forms above it.
A rhizome is a horizontal stem that grows underground or on the surface. It divides and produces new buds and shoots along its branches.
GERMINATION OF A RUNNER BEAN
Most seeds require damp, warm conditions in order to sprout. During germination, the seed absorbs water and the embryo starts to use its food store. A young root, or radicle, begins to grow downward. Then a young shoot, or plumule, grows upward. This develops into the stem and produces leaves. The first leaves, called seed leaves or cotyledons, fuel the early growth until the plant’s true leaves appear.
A flower’s ovary usually develops into a fruit to protect the seeds and help disperse them. A fruit may be succulent (fleshy) or dry. Fruit is often tasty and colourful to attract fruit-eating animals. Its seeds can pass through an animal unharmed, falling to the ground in droppings. Seeds may also be dispersed on animals’ coats, by the wind, or by the fruit bursting open.
The seeds of dry fruits are dispersed in various ways. Peapods are dry fruits that split and shoot out their seeds by force. The hogweed fruit forms a papery wing around the seed, helping it to float on the breeze. The strawberry is a false fruit, but it is covered by tiny dry fruits, each with a seed.
Fleshy, brightly coloured, and often scented, succulent fruits are designed to attract the animals that eat and disperse them. Fleshy fruits such as apricots and cherries have a woody stone or pip that protects the seed. Called drupes, these fruits form from a single ovary. Many drupes, formed from many ovaries, may cluster to form a compound fruit, such as a raspberry.Most plants grow from seeds. These seed plants fall into two groups, angiosperms and gymnosperms. Angiosperms are the flowering plants. Their seeds de
What Are Some Examples of Plants With Seeds?
By: Sophie Johnson
21 September, 2017
Plants that produce seeds are either gymnosperms, which make seeds in cones, or angiosperms, which create seeds with flowers. This means that all conifers and all flowering plants bear seeds. Gymnosperms and angiosperms reproduce sexually; that is, they have male and female aspects. Pollen, for instance, contains “male” sperm that must fertilize “female” ovules for successful reproduction to occur. The outcome of that reproduction is seed.
Anise is an herb plant that is grown for its seeds, which have a licorice flavor. The plant is an annual, which means it completes its life in one season–germinating, producing clusters of flowers and then seeding. The plant grows about 2 feet high, enjoying full sun and a well-draining soil. Seedheads are harvested when they turn pale gray.
- Plants that produce seeds are either gymnosperms, which make seeds in cones, or angiosperms, which create seeds with flowers.
- The plant is an annual, which means it completes its life in one season–germinating, producing clusters of flowers and then seeding.
Caraway is another herb that produces seeds for eating. The plant is a biennial, living its life in the space of two growing seasons. The first season, caraway produces vegetation. During its second and last season, the plant reaches its full height of about 2 feet and flowers with small white blooms, which create seeds that ripen to brown by the middle of the summer. At that point, the seeds can be harvested and the plant dies. Like anise, caraway is a sun-lover that likes well-drained soil. It doesn’t do well along the Gulf Coast of the United States.
- Caraway is another herb that produces seeds for eating.
- The plant is a biennial, living its life in the space of two growing seasons.
Mimosas are trees originally from Asia that, as members of the legume family of plants, produce seeds in pods. Before producing the seed pods, the tree blooms in clusters of flowers that look like spiky pink pom-poms. In some places, the tree is considered invasive due the tree’s ability to sprout back from being cut, the fact that it’s a non-native of the United States, and the way it can establish itself apart from where it was originally planted. Seeds can stay viable for decades. Still, its interesting appearance makes the tree a popular ornamental.
Tomato plants, like many plants grown for food, have obvious seeds contained within the fruit. The fruit of flowering plants is actually a mature ovule. Of the three types of tomatoes–determinates, semideterminates and indeterminates–indeterminates are easiest to grow. These are vining tomatoes, producing fruit until frost puts a stop to it. Determinates and semideterminates are bushy, the first growing up to about 18 inches, the latter growing up to 2 feet high. Both stop producing fruit when they’ve achieved full height.Plants that produce seeds are either gymnosperms, which make seeds in cones, or angiosperms, which create seeds with flowers. This means that all conifers and all flowering plants bear seeds. Gymnosperms and angiosperms reproduce sexually; that is, they have male and female aspects. Pollen, for instance, contains … ]]>