There are two main sources of energy for autotrophs, one is light energy conversion, and the other is chemical synthesis. Among them, chemical synthesis refers to the process of synthesizing organic matter through a series of chemical reactions by using ATP and NADPH produced by photosynthesis. This process occurs in the photosynthetic system of plant chloroplasts and includes two stages: light reaction and dark reaction. In the photoreaction, light energy is captured and converted into chemical energy to generate ATP and NADPH；; In dark reactions, ATP and NADPH are used to convert carbon dioxide and water into organic substances, such as glucose. This process is an important way for autotrophs to maintain their lives and develop.

Chemical synthesis is one of the most important energy sources of autotrophs, which provides a lot of organic matter and energy for the growth, reproduction and adaptation of autotrophs. The importance of chemical synthesis is not only reflected in plants, but also involves the survival and metabolism of many microorganisms. Through this process, autotrophs can not only use light energy for their own metabolism and life activities, but also provide nutrients and energy for other organisms to maintain the balance and stability of the whole ecosystem.