Photosynthesis of Orchid

The photosynthesis of orchids mainly depends on the absorption of light energy by chlorophyll in leaves, which makes carbon dioxide and water into organic matter, releases oxygen, and converts light energy into chemical energy, which is stored in the organism. Its main function is to convert inorganic matter into organic matter and store it in various organs. From this, we can understand that light is the key to orchid photosynthesis, the necessary condition to maintain orchid life, and the driving force for orchid growth.

one。 The mechanism of photosynthesis of orchids:

The photosynthesis of orchids is not a simple process, it can be divided into two steps: light reaction and dark reaction. Light reactions can only be carried out with light, while dark reactions can be carried out with or without light. In strong light, the photosynthetic rate was affected by temperature in a certain range, and accelerated with the increase of temperature, and the light reaction was rapid. The whole process of light reaction will be limited by temperature and dark reaction. In the light reaction, the water is decomposed by the light energy absorbed by chlorophyll, that is, with the help of chlorophyll, the water is decomposed into hydrogen and oxygen atoms, and the hydrogen and oxygen atoms form water and release oxygen. The next step in photosynthesis is the dark reaction, which is the fixation and reduction of carbon dioxide. The hydrogen atoms decomposed in the photoreaction are transferred to carbon dioxide molecules through different compounds using chlorophyll as the carrier. Before carbon dioxide can be reduced, it must be fixed into a compound before it can be reduced to organic matter by hydrogen.

two。 Products of photosynthesis of orchids:

The direct products of orchid photosynthesis are carbohydrates, including monosaccharides, disaccharides and polysaccharides, among which sucrose and starch are the most common. There are also proteins, fats and organic acids, which account for a small proportion and are re-synthesized through intermediates of carbohydrate metabolism. These substances will again synthesize a variety of other organic compounds, such as nucleic acids. Auxin. Lignin. Vitamins Plant alkaloids. Anthocyanin and so on. The number of various products of photosynthesis and the age of plants. There is a certain relationship between light and nutrient elements. Young leaves produce more protein, so they are softer. With more light, more carbohydrates are produced, so the leaves are stiff and easy to knot. More carbohydrates are synthesized under red light and more proteins are synthesized under blue light. With the increase of nitrogen nutrition, more protein is produced, otherwise there are more carbohydrates. Therefore, in the case of high nitrogen and weak light, more proteins are formed in the orchid leaves, which can easily cause the orchid plants to grow too long and the leaves soft and lodging.

three。 Factors affecting photosynthesis of orchids:

Like other physiological processes, the photosynthesis of orchids is affected by a series of internal and external factors. The degree of aging of orchid organs. The content of chlorophyll in vivo and external environment have a direct effect on the photosynthesis of orchids. This paper mainly analyzes the influence of external environment on orchid photosynthesis.

1. Light intensity: light is the key to photosynthesis and the energy source of photosynthesis. without light, orchids cannot photosynthesize. There is a close relationship between light intensity and photosynthetic intensity. The commonly used unit of light intensity is lux, which can be measured directly by illuminator. the light intensity of bare land is more than 100000 lux in sunny day in summer, about 25000 lux in sunny day in winter, and less than 10% in cloudy and rainy day. The above data are in Jiangsu and Zhejiang, and the light intensity is different in different areas. Chunlan. The suitable light intensity of lotus petal orchid and spring sword is 6 000 ~ 10 000 lux, while that of Cymbidium and Cymbidium is higher, 9 000 ~ 14 000 lux, 4 000 ~ 6 000 lux, and the light intensity of Yilan should be decreased accordingly. In general, orchids can carry out photosynthesis under weak light, and the weaker the light is, the weaker the photosynthesis is; if the light intensity increases, the photosynthesis also increases. However, when the light intensity reaches a certain degree, when the light intensity increases to the light saturation point, the photosynthesis will no longer increase, and if the light intensity continues to increase, the photosynthesis of orchids will decrease, and at the same time, strong light will often lead to high temperature. it is easy to cause water shortage in leaves and stomatal closure, which leads to insufficient supply of carbon dioxide. Thus it can be seen that the Chinese orchid is a shade-tolerant plant. When the light intensity is strong, shading is needed to reduce the light intensity so that the orchid can photosynthesize normally.

two。 Carbon dioxide concentration: carbon dioxide is the main raw material of photosynthesis, its content will directly affect the progress of photosynthesis. In general, the most suitable concentration of carbon dioxide for photosynthesis of orchids is 0.1%, while the content of carbon dioxide in the air is usually about 0.03%. If the concentration of carbon dioxide in the air is properly increased within a certain range, photosynthesis can be significantly increased. When orchids are cultivated in greenhouse, carbon dioxide fertilization can be used to increase the content of carbon dioxide in the air. I haven't tried it. I don't know what its effect is. I hope the orchid you who have used it can introduce it in detail. In addition, the concentration of indoor carbon dioxide can also be increased by organic fermentation. However, when the concentration of carbon dioxide in the air is too high, it is also disadvantageous to orchid photosynthesis. when the concentration is more than 1%, it will cause orchid protoplast poisoning and stomatal closure, thus inhibiting photosynthesis. at this time, if the light intensity is increased, the utilization concentration of carbon dioxide can be relatively increased. Therefore, ventilation should be installed in the blue room. Air exhaust and lighting equipment.

3. Temperature: in general, orchids can photosynthesize normally at 5-36 degrees, and the most suitable temperature is 15-30 degrees. Below 5 degrees, photosynthesis is inhibited. From the low limit of temperature, photosynthesis increases with the increase of temperature, but when it exceeds 36 degrees, photosynthesis will be very weak or even stop. The effect of temperature on orchid photosynthesis is directly related to light intensity and carbon dioxide concentration. In a certain range, under the condition of higher light intensity and higher carbon dioxide concentration, photosynthesis will also be enhanced. When the light intensity and carbon dioxide concentration are low, the increase of temperature is disadvantageous to the growth of orchids. Therefore, when orchids are cultivated in greenhouse, heating equipment should be equipped with lighting equipment to achieve good results. The temperature in the orchid room should be appropriately reduced at night or on rainy days to increase the temperature difference and promote dry matter accumulation.

4. Water: water is the raw material of photosynthesis, but less than 1% of the water absorbed by orchids is used for photosynthesis, while most of the water is used in other physiological processes and is lost through transpiration. Therefore, the effect of water on photosynthesis is not direct, but mainly affects other physiological activities, thus indirectly affecting photosynthesis. When the water metabolism of the orchid is destroyed, the leaf moisture decreases, causing the stomata to close, preventing the entry of carbon dioxide, thus affecting the photosynthesis of the orchid.

5. Nutrient elements: nutrient elements also have a certain effect on orchid photosynthesis. Magnesium and nitrogen are components of chlorophyll; iron and manganese are involved in the formation of chlorophyll; boron. Potassium. Phosphorus can promote the transport and transformation of organic matter. Therefore, rational fertilization plays a very important role in the smooth progress of orchid photosynthesis. (Xinyuanxuan)