Plants

Plants (Botanical)

Plants, also known as the kingdom Plantae, are multicellular organisms in the domain Eukaryota that use photosynthesis to make their own food. They are characterized by their green color due to the pigment chlorophyll, which is involved in capturing light energy. Plants play a crucial role in the Earth's ecosystems, providing oxygen, food, shelter, and a foundation for most food chains.

Classification

The plant kingdom is divided into several groups, including mosses, ferns, conifers, and flowering plants. This classification is based on reproductive characteristics, the presence or absence of vascular tissue, and other morphological features.

• Mosses (Bryophyta) - Non-vascular plants that reproduce via spores and have a life cycle dominated by the gametophyte stage.
• Ferns (Pteridophyta) - Vascular plants that reproduce via spores and have a distinct alternation of generations between the sporophyte and gametophyte.
• Conifers (Coniferophyta) - Cone-bearing plants with vascular tissue, reproducing through seeds produced in cones.
• Flowering Plants (Angiosperms) - The largest group of plants, characterized by the production of flowers and seeds enclosed within a fruit.

Structure and Function

Plants are composed of various organs and tissues that perform specific functions. Key structures include roots, stems, leaves, flowers, and seeds.

• Roots - Organs that anchor the plant and absorb water and nutrients from the soil.
• Stems - Support the plant, transport water and nutrients, and house the majority of photosynthetic activity.
• Leaves - The primary sites of photosynthesis, responsible for converting sunlight into chemical energy.
• Flowers - Reproductive structures that produce seeds for propagation.
• Seeds - Encapsulate the embryonic plant and facilitate dispersal to new growing sites.

Photosynthesis

Photosynthesis is the process by which plants convert carbon dioxide and water into glucose and oxygen, using sunlight as the energy source. This process is crucial for the survival of life on Earth, as it produces the oxygen necessary for respiration and forms the basis of most food chains.

Glossary

• Botany - The scientific study of plants, including their physiology, structure, genetics, ecology, distribution, classification, and economic importance.
• Chlorophyll - A green pigment found in the chloroplasts of plants, algae, and some bacteria, essential for photosynthesis.
• Photosynthesis - The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.
• Vascular tissue - Specialized tissue in plants that conducts water and nutrients. It consists of xylem and phloem.
• Xylem - The vascular tissue in plants that conducts water and dissolved nutrients upward from the root.
• Phloem - The vascular tissue in plants that conducts sugars and other metabolic products downward from the leaves.
• Gametophyte - The sexual phase in the life cycle of plants and algae that undergo alternation of generations, producing gametes.
• Sporophyte - The asexual phase in the life cycle of plants and algae that undergo alternation of generations, producing spores.
• Angiosperms - A group of plants that are characterized by having flowers and fruit with seeds inside. They are the most diverse and widespread plant group.
• Gymnosperms - A group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes. They are characterized by the absence of an outer fruit layer around the seed.
• Metabolism - The set of life-sustaining chemical reactions in organisms, involving the conversion of energy from nutrients.
• Ecology - The branch of biology that deals with the relations of organisms to one another and to their physical surroundings.

Also see

• USDA list of plants
• Glossary of plant materials