Photosynthesis mainly occurs in green leaves. Due to the flat shape of the leaf blade, the leaf has a large contact surface with air and sunlight. Photosynthesis takes place in chloroplasts. During this process, due to the energy of sunlight, the plant, with the help of green chlorophyll from the leaves, forms the organic substances it needs from inorganic ones – carbon dioxide and water. Photosynthesis is always supported by root nutrition – the absorption of water and mineral salts from the soil. Photosynthesis does not occur without water.
Photosynthesis is a very complex multi-step process that consists of two main stages.
Stage 1 (light phase)
A prerequisite is the participation of solar energy!
The process starts with light. It activates chlorophyll (a substance found in chloroplasts). And activated chlorophyll breaks down the water molecule into hydrogen and oxygen. Oxygen is released into the air.
Stage 2 (dark phase)
This stage of photosynthesis is called dark, because here all processes take place without the participation of light. At this stage, in the course of many chemical reactions involving carbon dioxide and active components obtained at the first stage of photosynthesis, an organic substance (carbohydrate) is formed – sugar (glucose).
Plant use of photosynthetic products
The entire complex step-by-step process of photosynthesis goes on in chloroplasts without interruption, while the green leaves receive solar energy. Glucose is converted almost immediately into other carbohydrates such as starch. These organic substances flow through the sieve tubes of the bast from the leaves to all parts of the plant: to the buds, generative organs. Other organic substances, including proteins and fats, are formed from glucose and minerals in plant cells during numerous transformations.
All these organic substances go to the growth and development of the plant – that is, to build its body, and are also deposited in storage tissues and are used during respiration.