Respiration

Respiration probably isn’t what you think it is, especially when it comes to plants.

Most of us think of ‘respiration’ as the breathing in and out that we do to oxygenate our blood. But that’s only part of the story. Respiration refers to any process within a living thing that uses a gas exchange to generate or release energy.

Plant respiration

Plants respire through root hairs, outer stem cells, and tiny holes on the underside of leaves called stomata. The stoma can be opened for respiration or closed to conserve water. [In extreme heat, plant respiration can be reduced by as much as 50% due to stomata closure.] The oxygen that enters through the stoma then moves to individual plant cells, where it is used in several different cellular functions. These chemical reactions produce carbon dioxide, which is released by diffusion. Iron and potassium are important components of this process.

Respiration as energy production

We all know that plants absorb water through the roots and create sugars in the leaves using photosynthesis. Those sugars travel through the phloem to the mitochondria of most plant cells, where they are oxidized, or broken down, by oxygen molecules. The oxygen breaks the sugar molecules into carbon dioxide, water, and storable energy, called ATP (adenosine triphosphate).

Respiration and photosynthesis

Everything switches while photosynthesis is taking place. When a plant is actively producing energy from light, carbon dioxide is inhaled and converted into sugar, and oxygen is exhaled. This is called the Krebs Cycle. This means that your plants are providing you with oxygen during the day, and taking it back at night. Thus, the Eternal Balance of oxygen and carbon dioxide in nature is maintained.

You may be surprised to learn, as I was, that respiration without oxygen (anaerobic) is called fermentation. When plants try to respire without oxygen, they make alcohol!​​