Harry’s World: Photosynthesis

Photosynthesis is one of the most important aspects of plant growth, but how does this process actually work?

Photosynthesis involves turning the sun’s energy into chemical energy that a plant can process and use to grow. What is the light from the sun? It is actually something known as PAR or Photosynthetically active radiation. This is used to describe a certain wavelength that is between 400 to 700 nanometers, and the specific wavelength that plants use during photosynthesis. PAR is measured in µmols.

Plants can only absorb a certain amount of µmols, generally between 1100 and 1300. This designation is important to remember because often when buying lights to grow with manufacturers discuss lumens, which is useless as lumens is what the human eye can detect. The plant absorbs the light from the red and blue wavelengths due to the high amount of chlorophyll in the leaves.

So how does this radiation coming off the sun get absorbed into the plant and turned into important nutrients? This occurs via the cell walls, which are comprised of cellulose. Cellulose is a form of specialized sugars and is known as a structural carbohydrate because it is used to support and protect the plant. Humans have skeletons keeping us upright, but plants have cell walls comprised of cellulose.

How do the cell walls work? There are small holes called plasmodesmata, which allows nutrients in. Water can be lost from the cell walls when plants transpire, which is why you see the leaves droop when the plant isn’t getting enough water.

Basically the plant absorbs the sunlight through the leaves and the cell membranes buried deep within. It converts these lightwaves into sugars. Synthesizing the CO2 and H2O into sugar and oxygen, which the plant uses as food. The “photo” part of photosynthesis comes from the Greek word “phos,” meaning light. The process explained above represents the synthesis part.

I hope this gives you a bit more insight into the biological workings of your plants, giving you a bit more insight into how your plant lives.

Keep on growing!