Why Do Plants Need Air to Survive?

Plants use carbon dioxide that animals exhale.

The earth's atmosphere contains three gases vital to plant life: oxygen, carbon dioxide and nitrogen. These gases are exchanged or used internally by plants to transpire or make food. Air allows the sun's energy to heat the earth and create weather, such as warmth and water, which is needed for plant life.

Weather

Weather is caused by movement of various air masses of different temperatures.

If there was no atmosphere on earth, the sun's energy would not translate into warmth. The sun heats the air, causing wind. As air moves it picks up water vapor and as air temperatures change, clouds and precipitation form. Without water, plants cannot live, regardless of their location on the planet.

Nitrogen

The majority of the air is made up of nitrogen. Falling rain is inundated with nitrogen gas molecules that are trapped and carried in the water droplets to the soil, providing nourishment to plants.

Carbon Dioxide

Plant life absorbs carbon dioxide gas from air to form carbohydrates during the process of photosynthesis. The carbon atom in carbon dioxide is needed to form the basic molecule of sugars, the food needed for plants to grow.

Oxygen

Although plants do not need large amounts of oxygen for its plant cell processes, a lack of oxygen on earth would prevent animal life from respiring and releasing carbon dioxide. Carbon dioxide is necessary for plants to form sugars during photosynthesis.

Soil Porosity

Bald cypress trees have protruding "knees" of roots for gas exchange.

Air exists in soil to varying degrees, allowing for water molecules to move into topsoil layers. Compacted soils have diminished air pockets between soil particles, and can cause asphyxiation of roots, especially if plants are not adapted to wet or dense, heavy soils.

References

• Estrella Mountain Community College: Photosynthesis
• The Earth's Atmosphere

Resources

• Composition of Air