Post #4 The Function of CO2 in Your Growing Plants

INTRODUCTION: Carbon dioxide (CO2) is crucial for plant growth, as they use it to create food through photosynthesis. This process converts sunlight into chemical energy in the form of carbohydrates, such as glucose, using water and CO2 as the main ingredients. CO2 enters the leaf through stomata and is eventually transformed into a sugar called glyceraldehyde-3-phosphate (G3P) in the Calvin cycle. Plants use these carbohydrates to grow and develop, as well as store them as starch for energy when photosynthesis is not possible. Approximately 95% of a plant's dry weight comes from CO2 fixed by photosynthesis, with the remaining 5% being minerals and nutrients absorbed from the soil. Thus, plants are primarily composed of air and water, aided by sunlight and soil nutrients. Carbon dioxide (CO2) is a vital gas for plants, as they use it to make their own food through a process called photosynthesis. In this article, we will explain how CO2 is used by plants and how much of a plant's bulk is derived from CO2.

The Function of CO2 in Your Growing Plants

Photosynthesis is the process whereby plants convert the energy from the sun into a chemical carbohydrate molecule, such as glucose. To do this, plants need two main ingredients: water (H2O) and carbon dioxide (CO2). Water is absorbed by the roots and transported to the leaves, where it is split into hydrogen and oxygen by a complex set of reactions involving chlorophyll, the green pigment in plants. Oxygen is released as a by-product, while hydrogen is used to reduce CO2 into carbohydrates.

CO2 enters the interior of a leaf through tiny pores called stomata, which can open and close depending on the environmental conditions. CO2 diffuses into the stroma of the chloroplast, the site of the Calvin cycle reactions, where sugar is synthesized. The Calvin cycle is a series of reactions that use the energy from light-dependent reactions (which occur in the thylakoid membranes of the chloroplast) to fix CO2 into organic molecules. The main product of the Calvin cycle is a three-carbon sugar called glyceraldehyde-3-phosphate (G3P), which can be used to make glucose and other carbohydrates.

Plants use these carbohydrates to grow and develop, as they provide the building blocks for cell walls, proteins, nucleic acids, lipids, and other biomolecules. Plants also store some carbohydrates as starch in their roots, stems, seeds, and fruits, which can be used as a source of energy when photosynthesis is not possible (such as at night or during winter).

So how much of a plant's mass comes from CO2? The answer is most of it. According to one estimate, about 90-95% of the dry weight of a plant (excluding water) is carbon-based, meaning it ultimately comes from CO2 fixed by photosynthesis. The remaining 5% consists of minerals and nutrients absorbed from the soil. This means that plants are essentially made from thin air and water, with a little help from the sun and the soil.