Parts of a Flowering Plant

Casablanca Lily
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Plants are eukaryotic organisms that are characterized by their ability to produce their own food. They are vital to all life on earth as they provide oxygen, shelter, clothing, food, and medicine for other living organisms. Plants are very diverse and include organisms such as mosses, vines, trees, bushes, grasses, and ferns. Plants can be vascular or nonvascular, flowering or nonflowering, and seed bearing or non-seed bearing.

Angiosperms

Flowering plants, also called angiosperms, are the most numerous of all the divisions in the Plant Kingdom. The parts of a flowering plant are characterized by two basic systems: a root system and a shoot system. These two systems are connected by vascular tissue that runs from the root through the shoot. The root system enables flowering plants to obtain water and nutrients from the soil. The shoot system allows plants to reproduce and to obtain food through photosynthesis.

Root System

The roots of a flowering plant are very important. They keep the plant anchored in the ground and obtain nutrients and water from the soil. Roots are also useful for food storage. Nutrients and water are absorbed through tiny root hairs that extend from the root system. Some plants have a primary root, or taproot, with smaller secondary roots extending from the main root. Others have fibrous roots with thin branches extending in various directions.

All roots do not originate underground. Some plants have roots that originate above ground from stems or leaves. These roots, called adventitious roots, provide support for the plant and may even give rise to a new plant.

Shoot System

Flowering plant stems, leaves, and flowers make up the plant shoot system.

  • Plant stems provide support for the plant and allow nutrients and water to travel throughout the plant. Within the stem and throughout the plant are tube-like tissues called xylem and phloem. These tissues carry water, food, and nutrients to all parts of the plant.
  • Leaves are the sites of food production for the flowering plant. It is here that the plant acquires light energy and carbon dioxide for photosynthesis and releases oxygen into the air. Leaves can have various shapes and forms, but they all basically consist of a blade, veins, and a petiole. The blade is the flat extended part of the leaf. The veins run throughout the blade and provide a transport system for water and nutrients. The petiole is a short stalk that attaches the leaf to the stem.
  • Flowers are responsible for seed development and reproduction. There are four main flower parts in angiosperms: sepals, petals, stamens, and carpels. The stamen is considered the male portion of a plant and the carpel is considered the female portion. Pollen is produced in the stamen and the female ovary is contained within the plant carpel. Pollen is transferred from stamen to carpel by plant pollinators such as bugs, birds, and mammals. When the ovule (egg cell) within the ovary becomes fertilized, it develops into a seed. The ovary, which surrounds the seed, becomes the fruit. Flowers that contain both stamens and carpels are called perfect flowers. Flowers that are missing either stamens or carpels are called imperfect flowers. If a flower contains all four main parts (sepals, petals, stamens, and carpels), it is called a complete flower.

    Sexual Reproduction and Flower Parts

    Flowers are the sites of sexual reproduction in flowering plants. The stamen is considered the male portion of a plant because it is where sperm is produced and housed within pollen grains. The carpel contains the female reproductive organs.

    1. Sepal: This typically green, leaf-like structure protects the budding flower. Collectively, sepals are known as the calyx.
    2. Petal: This plant structure is a modified leaf that surrounds the reproductive parts of a flower. Petals are typically colorful and often scented to attract insect pollinators.
    3. Stamen: The stamen is the male reproductive part of a flower. It produces pollen and consists of a filament and an anther.
      • Anther: This sac-like structure is located at the tip of the filament and is the site of pollen production.
      • Filament: A filament is a long stalk that connects to and holds up the anther.
    1. Carpel: The female reproductive part of a flower is the carpel. It consists of the stigma, style, and ovary.
      • Stigma: The tip of the carpel is the stigma. It is sticky in order to collect pollen.
      • Style: This slender, neck-like portion of the carpel provides a pathway for sperm to the ovary.
      • Ovary: The ovary is located at the base of the carpel and houses the ovules.

    While flowers are necessary for sexual reproduction, flowering plants can sometimes reproduce asexually without them.

    Asexual Reproduction

    Flowering plants are able to self-propagate through asexual reproduction. This is accomplished through the process of vegetative propagation. Unlike in sexual reproduction, gamete production and fertilization do not occur in vegetative propagation. Instead, a new plant develops from parts of a single mature plant. Reproduction occurs through vegetative plant structures derived from roots, stems, and leaves. Vegetative structures include rhizomes, runners, bulbs, tubers, corms, and buds. Vegetative propagation produces genetically identical plants from a single parent plant. These plants mature faster than and are sturdier than plants that develop from seeds.

    Summary

    In summary, angiosperms are differentiated from other plants by their flowers and fruit. Flowering plants are characterized by a root system and a shoot system. The root system absorbs water and nutrients from the soil. The shoot system is composed of the stem, leaves, and flowers. This system allows the plant to obtain food and to reproduce.

    Both the root system and shoot system work together to enable flowering plants to survive on land. If you would like to test your knowledge of flowering plants, take the Parts of a Flowering Plant Quiz!