Effect of Orchid Culture Environment on Mineral absorption of Orchid

Temperature cultivation substrate temperature has a significant effect on the absorption of mineral elements. The rate of mineral absorption by roots increases with the increase of substrate temperature, but too high or too low temperature will greatly reduce the amount of mineral absorption. At low temperature, the viscosity of the protoplast increases, which increases the resistance to ions. When it is close to O degree, the active absorption almost stops completely, and there is only passive absorption, so the absorption of mineral elements is very weak. Too high temperature (more than 30 degrees or even 40 degrees) will also weaken the absorption of minerals by roots, because the high temperature gradually passivates the enzymes, affecting the normal metabolism of the pole and also affecting the absorption of minerals. Therefore, the humidity is too low, the soil temperature is too high, should be watered or humidified as appropriate, with water to adjust the temperature.

Under aeration conditions, the viscous weight of substrate or too much water will cause poor ventilation of orchid plants, affect the root activity of orchid plants, reduce the energy supplied for mineral absorption and transport, and thus reduce the absorption capacity of mineral elements. Because of poor ventilation, it directly affects the respiration of the root system.

The acidity and alkalinity of the cultivation substrate affects the solubility of mineral salts, so it has a great influence on mineral absorption. When the alkalinity of culture medium solution increased, the solubility of iron, copper, zinc, calcium, magnesium and phosphorus decreased, thus the absorption decreased. When the acidity of the solution increases, it can increase the solubility of various metal ions, which is beneficial to the utilization of plants, but it is easy to be leached. The most suitable PH value for the growth of Lanlin should be neutral or slightly acidic.

If the concentration of cultivation medium solution is too high, it will reduce the water potential of cultivation substrate solution, affect the water absorption of roots, and hinder the absorption of mineral elements by plants. Therefore, when applying fertilizer, it is necessary to apply fertilizer thinly and diligently in order to facilitate the effective use of fertilizer.

The interaction between ions the existence of one ion affects the effectiveness of another ion, and some show promotive effects, such as phosphorus and potassium can promote the absorption and utilization of nitrogen. The proper combination of nitrogen, phosphorus and potassium has a good effect on increasing the growth of orchid plants. The existence of some ions or too much often inhibit the absorption and utilization of other ions, such as excessive phosphorus often lead to zinc deficiency symptoms. Therefore, the balance of ions should be considered when applying fertilizer.

In addition, the microbial activity of the cultivation substrate, the light intensity and the growth of the root system itself affect the mineral absorption. In the process of cultivation, the optimal conditions for mineral absorption should be created as far as possible to make the orchid forest grow well.

After the mineral ions entered the root, except that some of them were intercepted by special cells, most of them entered the essential part of the stele, and then some of them were transformed into organic matter, but most of them were still in the form of free ions and went up to the aboveground organs with transpiration. The mineral ions absorbed by the roots can be transported up the phloem, and the mineral ions absorbed by the leaves can be transported downward in the phloem. The main reason is that the phloem of the plant can transport mineral elements in both directions.

After transpiration sends mineral elements to the parts that need the most minerals, such as growing points, young leaves, etc., they immediately participate in metabolic activities. Some elements are involved in tissue composition, such as nitrogen and phosphorus in the composition of protoplast, magnesium in the composition of chlorophyll and so on. Among the mineral elements, some elements, such as helium, phosphorus, potassium and magnesium, can be transported from the parts with weak metabolism to the parts with strong metabolism. When these elements are lacking in the environment, they can be transferred from the old leaves to the tender leaves to ensure the normal growth of the leaves. These elements are reused. When lacking these elements, the old leaves are the first to show symptoms. Therefore, in the process of cultivation, the old leaves are often prone to disease or dry up affected by environmental factors. Most of the elements that can be used repeatedly are distributed in the parts with strong metabolism, such as growing points and tender leaves.

Other elements, such as calcium, iron, boron, zinc, aluminum and copper, are fixed and can not be reused after being absorbed by the aboveground part of the plant. The older the organ of the plant is, the greater the content of this element is. For example, the content of calcium in the old leaf is much higher than that in the young leaf. Therefore, the old leaves in the orchid plant are more straight, the tender leaves are softer, and when these elements are lacking in the plant, the disease is easy to occur in the young leaves. Therefore, the young leaves of new buds in Lanshu are more prone to "rot" and "water injury". (Liu Zhongjian)