Plants are one of the main forms of life, including trees, shrubs, vines, grasses, ferns, green algae, lichens and other familiar creatures. Plants can be divided into seed plants, algae plants, bryophytes, ferns and so on.
Most of the energy of green plants is obtained from sunlight through photosynthesis, and temperature, humidity, light and fresh water are the basic needs of plant survival. Seed plants have six organs: roots, stems, leaves, flowers, fruits and seeds. Green plants have the ability of photosynthesis-with the help of light energy and chlorophyll, under the catalysis of enzymes, water, inorganic salts and carbon dioxide are used for photosynthesis, releasing oxygen, absorbing carbon dioxide and producing organic substances such as glucose for plants to use.
The role of plants
1. Plants are primary producers in nature: through photosynthesis, plants convert carbon dioxide into carbohydrates, release oxygen and store energy. Carbohydrates are further converted into lipids, protein and other organic substances in plants, and most of these organic substances are stored in various organs of plants as biological energy, except that some of them are used to maintain their own life activities and form the structure of plants. It is estimated that plants on the earth synthesize about 2605 billion tons of organic matter every year, which is equivalent to saving 3 * 10 2 1 joule of chemical energy every year. The value is amazing.
2. The role of plants in natural material circulation: plants not only have the function of synthesizing and storing organic matter, but also have the function of decomposing organic matter, that is, mineralization. Through the synthesis and decomposition of photosynthesis and mineralization of plants, the substances in nature can be circulated and maintained in a certain balance. On the one hand, mineralization decomposes organic matter into carbon dioxide and water through the respiration of animals and plants, on the other hand, it transforms complex organic matter into simple inorganic matter through the decomposition of dead organic matter by bacteria and fungi. The most important are carbon cycle and nitrogen cycle.
3. The role of plants in environmental protection: mainly reflected in its purification of the atmosphere, water and soil. The epidermis of plant leaves contains fur, mucus, grease, etc., which can absorb dust and toxic gases and enrich harmful substances. Some plants have high resistance and the ability to absorb and accumulate pollutants. Plants can purify air pollution, adjust climate, reduce noise and prevent dust. Plants also play an important role in soil and water conservation. Forest cover on the ground can reduce the loss of surface rainwater and the erosion of topsoil, and play a role in slope protection. Store water sources to prevent soil erosion. The transpiration of forest branches and leaves makes water vapor diffuse into the atmosphere, and the water vapor condenses into rain, which reduces the regional drought.