Microclimatic environment of Gastrodia elata cultivation

Gastrodia elata, also known as red arrow, Dingfeng grass, water potato, etc., is a famous Chinese and foreign precious medicinal materials, known as the "king of medicinal materials", with high medical and health care value. Gastrodia elata is usually referred to as its dry tuber. In terms of plant taxonomy, Gastrodia elata belongs to perennial herbs of Orchidaceae, but it is different from the green plants we often say, its plant is a fleshy single seedling, yellowish red, rootless, no green leaves, can not carry out photosynthesis. During the whole period of growth and development, it must "symbiosis" with a kind of fungus called Armillaria mellea and rely on its own lysozyme to dissolve the hyphae of Armillaria mellea, so as to obtain the water and nutrition of Armillaria mellea to maintain its own growth.

Gastrodia elata as a valuable traditional Chinese medicine, people should not only pursue yield, but also pay attention to quality, that is, to fully ensure the content of active ingredients, otherwise it is possible that "although the material is not fake, but the species is different, the medicinal properties are different". Only under specific environmental conditions can Chinese herbal medicines with specific medicinal properties and efficacy be produced. Yan Ying's famous saying in the Spring and Autumn period, "tangerine born in Huainan is orange, and born in Huaibei is trifoliate orange" vividly illustrates the environmental conditions, especially the importance of climatic conditions to the production of Chinese medicinal materials. Fructus Aurantii and orange peel are two commonly used Chinese medicinal materials, but their main treatment objects and efficacy are obviously different.

China has complex topography and a variety of climate types, especially in the vast mountain areas, there may be suitable areas for Gastrodia elata cultivation. In order to cultivate Gastrodia elata, it is necessary to understand the requirements of environmental conditions for the growth of Gastrodia elata. Only by selecting or creating a microclimatic environment suitable for the growth of Gastrodia elata according to local conditions, and using agricultural technical measures to fully meet the needs of the growth of Gastrodia elata, can we produce high-quality Gastrodia elata and obtain better economic benefits.

Temperature is the primary factor affecting the growth of Gastrodia elata. Gastrodia elata likes to grow in cool summer and not very cold in winter. It is sensitive to temperature. The temperature will directly affect the growth, yield and quality of Gastrodia elata. The effective accumulated temperature of Gastrodia elata from young to long is about 3800 ℃, and the commodity is better when it is about 4000 ℃. Generally speaking, when the ground temperature reaches more than 12 ℃, Gastrodia elata cells become active, and they can begin to digest and absorb Armillaria mellea as nutrients for their own growth and expansion, and the activity increases with the increase of temperature; the ground temperature reaches 20 ℃-25 ℃, which is the optimum temperature for the growth of Gastrodia elata and Armillaria mellea, and the growth and development of Gastrodia elata is the fastest at this time. However, when the soil temperature continued to rise above 30 ℃, the growth of Armillaria mellea and Gastrodia elata was inhibited, which was easy to produce aconitum. Therefore, attention should be paid to heat prevention and cooling in high temperature season. When the temperature was lower than 15 ℃, the growth rate of Gastrodia elata slowed down and gradually stagnated into overwintering dormancy. Gastrodia elata is more resistant to cold, as long as the soil temperature is higher than-4 ℃, it can survive the winter normally, but if it is lower than-5 ℃, it will cause the tuber of Gastrodia elata to suffer frost injury and rot, which will affect its safety in winter.

Gastrodia elata (Gastrodia elata for short) needs a certain low temperature dormancy in winter before it can germinate normally in spring. At the low temperature of 2 ℃-5 ℃, it takes about two months for seed hemp to pass through the dormancy period. If the low temperature time is not enough, even if the germination conditions are suitable, the seed hemp will not germinate. The speed of germination after the release of dormancy is also related to the low temperature conditions accepted during dormancy. The longer the low temperature treatment time is, the faster the germination speed is, and vice versa.

Wild Gastrodia elata is generally distributed in areas with annual precipitation of more than 1000 mm, air relative humidity of about 80% and soil water content of 50% Mel 55%. The rainy, rainy and humid climate is the most suitable for the growth of Gastrodia elata, especially in the peak growing season from June to August, the nutrient accumulation of Gastrodia elata reaches its peak and needs more water. Abundant rainfall in this period is the key to ensure the high yield of Gastrodia elata. In September, the nutrition accumulation of Gastrodia elata entered the later stage and reached the physiological mature stage, when the soil moisture should be controlled below 40%. If Rain Water is too much, Armillaria mellea grows vigorously, invades the new hemp and decomposes the Gastrodia elata tissue as nutrition, it will cause the rot of Gastrodia elata tubers, resulting in reduced yield or reduced quality.

Because Gastrodia elata is a non-green plant, the whole process of asexual reproduction is carried out underground from planting to harvest, so light has no direct effect on the growth and reproduction of underground tubers, but can only indirectly affect the change of soil temperature. If Gastrodia elata is cultivated in cool areas, increasing the exposure of direct light can increase the ground temperature. Gastrodia elata needs some scattered light after bolting (about two months), but avoid strong light, strong direct light will cause sunburn, harm the stem of Gastrodia elata, and easily lead to plant death. At the same time, direct sunlight will increase the evaporation of soil water, reduce soil moisture and affect the growth of tubers. Therefore, attention should be paid to setting up a shed for shade to reduce the exposure of direct light. The strong wind is only harmful to the bolting and flowering Gastrodia elata, which can break or blow down the flower and affect the seed yield. Therefore, the unearthed flower bolts should pay attention to the strong wind, such as kidnapping the unearthed flowers and so on.