On the Source of Carbon Dioxide in Plants
Between heaven and earth, all things grow, and plants flourish, which is related to the source of carbon dioxide. Looking at nature, there are many sources of carbon dioxide, which are crucial for plant growth.

First, in the atmosphere, carbon dioxide is stored. Wind and gas travel, and it distributes with the airflow. The pores of plant leaves are called solar stomata, which can accommodate external carbon dioxide. During the day, there is sufficient light, and plants perform photosynthesis. The stomata open, and carbon dioxide enters the interior. It meets with water and is transformed into carbohydrates and oxygen by chloroplasts. In this process, carbon dioxide provides carbon sources for plants, helping them build their bodies and thrive.

Second, in the soil, there is also carbon dioxide. Many kinds of microorganisms in the soil decompose organic matter, such as fallen leaves, residual roots, and animal excrement. As this decomposes, carbon dioxide is released. Around plant roots, the concentration of carbon dioxide varies. The root system can absorb this part of carbon dioxide, and the soil aeration status also affects the root system's uptake of it. If the aeration is good, carbon dioxide can easily reach the root system; if the aeration is not smooth, the root system uptake will be blocked.

Third, in the water body, carbon dioxide is also used by plants. Aquatic plants or wetland plants can obtain carbon dioxide in the water. Carbon dioxide in water is partly from the dissolution of the atmosphere, and partly from the respiration of organisms in the water body and the decomposition of organic matter. Aquatic plants use their special structure and physiological mechanism to absorb carbon dioxide in water, perform photosynthesis, and maintain their own growth and ecological balance.

Overall, carbon dioxide is a necessary resource for plant growth, just as grain is for people. The atmosphere, soil, and water are all its sources. The adequacy and stability of the source are related to the rise and fall of plants and the balance of ecology. Therefore, we should cherish nature and protect its smooth carbon dioxide cycle to ensure the flourishing of plants and ecological harmony.