The Importance of Plants

Just the Facts

Introduction to Plant Science

Presented by the National Agricultural InstituteFocus on supporting and enhancing postsecondary agriculture education with resources that promote best practices in agriculture.Revised in August 2016

Objectives

  • Contributions of Plants:

    • Identify two crucial contributions plants make to all other living organisms, such as providing oxygen and serving as the foundation of the food web.

  • Plant Products:

    • List three significant products derived from plants, including food, textiles, and various industrial materials.

  • By-Products:

    • Name three by-products that come from plants, like biofuels, paper, and medicinal compounds.

Chapter 1: Importance of Plants to Humans

Roles of Plants

Foundation of Ecosystems:

  • Photosynthetic processes in green plants form the base of the food chain and are integral to maintaining ecosystem stability and health.

  • Initiate energy flow through ecosystems, allowing energy transfer from one trophic level to another.

  • Incorporate essential inorganic elements, such as carbon, nitrogen, and phosphorus, into living tissues, promoting diversity and sustainability in environmental niches.

Photosynthetic Processes

Energy Cascade:

  • Energy is harnessed from the sun through photosynthesis, converting light energy into chemical energy in the form of glucose.

  • Provides nutrients to herbivores, such as Thomson's gazelle, which, in turn, support carnivores like hunting dogs in the ecosystem.

  • Heat from Earth's surface affects nutrient flow to carnivores, highlighting the interdependence of different species.

  • Nonliving inorganic materials contribute to ecological balance by cycling nutrients through various biological and physical processes.

  • Decomposition, carried out by fungi and bacteria, contributes significantly to nutrient recycling, thus maintaining soil fertility and health.

Energy and Oxygen Supply

Plant Contributions to Biomass:

  • Energy not directly utilized by plants is stored in new tissues, serving as food for herbivores, and eventually for carnivores, illustrating the importance of plants in the energy pyramid.

  • Plants produce oxygen as a by-product of photosynthesis, which is essential for the survival of nearly all living organisms on Earth, powering aerobic cellular respiration.

World Production of Edible Plants

Human and Livestock Food Sources:

  • Various plants provide essential food products for humans, significantly impacting nutrition and health.

  • Dominant forms of crops include starchy roots (like potatoes and cassava) and grains (like wheat, rice, and corn).

Legumes:

  • Legumes such as beans and lentils play a crucial role in human diets due to their high protein content and ability to fix nitrogen in the soil, improving soil health.

Soil Enrichment:

  • Nitrogen-fixing capabilities of legumes, facilitated by symbiotic bacteria (rhizobia) in root nodules, enhance soil health and agricultural productivity, demonstrating the importance of plants in sustainable agriculture.

Important Grain Plants

Key Staple Crops:

  • Major grains such as wheat, rice, maize (corn), sorghum, and barley are staple foods that provide the majority of calories for the global population.

  • Important beverages derived from plant sources include coffee (from Coffea beans), tea (from Camellia sinensis leaves), and fruit juices (from various fruits).

Industrial Uses

Textile Fibers:

  • Plants are foundational to many products, notably cotton (Gossypium), flax (Linum usitatissimum), and hemp (Cannabis sativa), which are key materials in the textile industry.

Wood Utilization:

  • Wood from trees is vital for a range of applications, including the production of tools, furniture, shelter, fencing, and roofing materials, signifying the role of plants in construction and craftsmanship.

Various Industrial Products:

  • Derived from plants, key industrial products include turpentine (from pine trees), dyes (from various plant sources), resin (from conifer trees), mulch (from organic waste), and decorative bark used in landscaping.

Medicinal Uses

Plant-derived Medicinals:

  • Quinine from cinchona bark is a historically significant anti-malarial drug that has saved countless lives.

  • Digitalis from foxglove leaves is utilized as a heart stimulant, emphasizing the importance of plants in modern medicine.

  • Atropine from belladonna is an antispasmodic used in various medical treatments, showcasing the role of plants in pharmacology.

  • Rauwolfia provides tranquilizing agents, illustrating the range of therapeutic applications available through plant derivatives.

World Oil Seed Production

Common Oil Plants:

  • Examples of oil plants include olives, palm, sunflower, peanuts, rapeseed (canola), cottonseed, coconut, and soybean, which are cultivated for their oil used in cooking, cosmetics, and biofuels.

Environmental Protection through Plants

Benefits of Vegetation:

  • Planting vegetation provides numerous ecological benefits, including shade, windbreaks, and erosion control, essential for maintaining healthy ecosystems.

  • Plants play a critical role in protecting watersheds and enhancing biodiversity, showcasing their importance in environmental conservation efforts.

Supporting Agricultural Education

  • Focused on enhancing agriculture, food, and natural resources education at the postsecondary level, promoting research, innovation, and best practices to prepare students for the challenges in agriculture today.