Top Image: Jon Sullivan - Wikimedia Commons

Overview

Image 1: Plant diagram
Source: Jon Sullivan, Wikimedia Commons

Plants, like animals, are organisms that live and grow around the world. Plants are members of the Kingdom Plantae and include grasses, trees, flowers, bushes, ferns, mosses and many more varieties. Most plants have three basic parts: leaves, stems and roots. Not all plants are the same; some have flowers and some have fruit. Plants can grow from seeds, corms, bulbs or tubers.

Leaves

Leaves are the part of a plant that is specialized for plant food production. Leaves capture energy from sunlight, as well as collect carbon dioxide from the air, while producing oxygen. Many leaves are flat and large in order to catch as much sunlight as possible. However, leaves come in many different shapes, including long skinny needles that are found on pine trees and cacti. The stem is the main structure that supports leaves and flowers. Stems transport food, water and nutrients around the plant to help it grow. Plants often store food in their stems.

Roots

Image 2: Schematic of photosynthesis in plants
Source: Riyasachdeva250, Wikimedia Commons

Roots of a plant normally grow underground. They can help to keep the plant upright and gather water and minerals. Some plants store food in their roots. The two major types of roots are fibrous roots and taproots. Taproots tend to have one major root that grows very deep, while fibrous roots have many roots that grow in all directions. Grasses have fibrous roots, as do corn and rye plants. Radishes, soybeans, carrots and parsnips are all examples of taproots.

Photosynthesis

Photosynthesis is the process of using the sun’s energy to convert carbon dioxide and water into oxygen and usable energy in the form of sugar (glucose).

  • Oxygen is produced during photosynthesis, some of which is used for plant respiration and the rest released into the air.
  • Glucose provides the energy for the plant to form and grow its leaves, stem, roots, fruits, flowers, bark on trees, etc.

Misconceptions

Misconception: Plants are not alive.

Correction: Plants may be different from animals in many ways, but they are like other living things that grow and reproduce.

Misconception: Trees, grass, vegetables, and weeds are not plants.

Correction: They are definitely plants and fall under the Kingdom called Plantae. Scientists are still cataloguing the number of plant species in the world, but current estimates vary from 200,000 up to 400,000 species. Plants come in many different shapes and sizes.

Misconception: Plants take in all substances they need to grow through their roots.

Correction: Only water and nutrients are taken in by their roots. Carbon dioxide and oxygen from the air as well as sunlight are all taken in through the leaves of the plant. Carbon dioxide and sunlight are necessary for the plant to make food, while oxygen is necessary for the plant to respire.

Misconception: Plants breathe by inhaling carbon dioxide and exhaling oxygen.

Correction: Plants do take in air through their leaves but they do not breathe. Carbon dioxide is used with water during photosynthesis to create sugar and oxygen. Plants use some of this oxygen in respiration but release the rest of it back into the air.

Did You Know?

  • Some plants are carnivorous, trapping and eating insects to obtain energy. The best known of these are the Venus flytrap and pitcher plants.
  • Often plants are rooted to the ground, but they may also be “rooted” in water (hydroponic), or in air, such as an orchid growing on the trunk of a tree (aeroponic).
  • A definition of herbs is that they come from the leaf of a plant (sage, bay, basil, oregano, mint, parsley and thyme) while a definition of spices is that they come from the seed, fruit, stem, bark or root (cloves, cinnamon, nutmeg, ginger, saffron, and turmeric).
  • If you hang a pail on a tree branch 3 metres from the ground, how high will the pail be in 50 years? It will still be 3 metres from the ground. The branches and tree trunk grow outwards; only the growing tip at the top of the tree grows upwards.

References

Plant Life Teachers Guide (Accessed November 14, 2016)
U.S. Department of Health and Human Services

Plants (Accessed November 14, 2016)
DK findout!