Environmental Conditions for the Growth of Gastrodia elata

1. Effect of temperature on the growth of Gastrodia elata

Effect of temperature on growth of Gastrodia elata: temperature is the main factor affecting the growth of Gastrodia elata. Gastrodia elata likes to grow in cooler summer and not very cold in winter. The longer the temperature suitable for its growth, the more beneficial to the growth of Gastrodia elata.

(1) effect of temperature on asexual reproduction of Gastrodia elata.

The underground tuber of Gastrodia elata began to grow when the ground temperature was about 14 ℃. The growth of 20 ℃ was faster and that of 30 ℃ was inhibited. The total accumulated temperature of the whole growing season in one year is about 3800 ℃. About 1000 meters above sea level, it is the most suitable for the growth of Gastrodia elata and Armillaria mellea.

When Gastrodia elata was introduced in low altitude or plain area, the ground temperature should be kept below 25 ℃. In the hot summer, the soil temperature lasted more than 25 ℃, the growth of Armillaria mellea and Gastrodia elata was inhibited, which affected the yield of Gastrodia elata. At the same time, the continuous high temperature also promoted the process of seed degradation of Gastrodia elata. Therefore, Gastrodia elata is cultivated in low altitude areas, and the summer high temperature season should be protected against heat and cool down.

Although Gastrodia elata can withstand cold, but there is a certain limit, can not suddenly cool down or continue ultra-low temperature. If the temperature suddenly decreases in early winter, Gastrodia elata will suffer frost damage. With the arrival of cold season, the temperature gradually decreases, the newborn tissue gradually ages, the water in the tuber cells of Gastrodia elata decreases, the concentration of cell sap increases, the freezing point of plants is reduced, the protoplast atrophy and protein solidification are prevented, and the cold resistance of Gastrodia elata is increased after cold resistance training. Gastrodia elata was under the condition of low temperature below zero for a long time, and no freezing injury was observed after a long time of low temperature training. Gastrodia elata, which grows in the cold northeast region, has a certain resistance to low temperature. For example, in Fusong County, Jilin Province, at an altitude of 774.2 meters above sea level, the average temperature in January is-15.7, and the lowest temperature can reach-34.7 ℃. Gastrodia elata is still distributed, but under these frozen environmental conditions, there must be thick snow cover for a long time, and the soil temperature in the distribution layer of Gastrodia elata is not lower than-5 ℃ before Gastrodia elata can survive the winter normally. If the snow is removed, Gastrodia elata will suffer frost damage.

In the process of systematic development, Gastrodia elata overwinters at a low temperature of about 0 ℃ for a long time in winter, so it needs low temperature during the overwintering period, and low temperature can break dormancy, so when the low temperature condition can not meet its requirements, the growth potential of buds after germination is weak, even if it is not rotten or germinated after planting. Low temperature treatment with 0 ℃-2 ℃ for 40 days broke dormancy and continued to germinate and grow. The experimental results of Shen Dongxia et al showed that after entering the dormancy period, the hemp tuber did not meet a certain low temperature time, even if the germination conditions were suitable, it would not germinate. Once the requirement of low temperature is met, when there is no suitable temperature condition, the tuber still does not germinate, but it can germinate when it meets the suitable germination condition. This is the crux of the problem that Gastrodia elata can hibernate for several months under natural conditions. Wan Huilan's test results show that white flax and rice hemp need 10 ℃ low temperature and 30 li 60 days to pass the dormancy stage. However, the size of seed hemp requires different time at low temperature and low temperature. Large, medium and white flax is about to enter the stage of reproductive growth, it is better to treat it at low temperature of 5 ℃ and 60 days, while small white hemp and rice hemp belong to vegetative growth stage. Dormancy can be broken with 10 ℃ and 30 ℃.

(2) the effect of temperature on the growth of flower stem.

In Hanzhong area of Shaanxi Province, when the local temperature rose to more than 10 ℃ in spring, the stem of Artemisia oleifera began to sprout, the soil 10cm soil temperature in the first ten days of May was about 15 ℃, and flowered when the temperature rose to 19.4 ℃-29.9 ℃ from late May to early June. The seed maturity period was from June 14 to the end of June, when the average temperature increased to 21.7mol-22.4℃. It took nearly 70 days for the temperature to rise from 15 ℃ to 22 ℃, and it took Gastrodia elata nearly 70 days to complete the whole process from emergence to seed maturation. The northwestern suburbs of Beijing are 50 meters above sea level. The stem buds of Gastrodia elata were unearthed when the 10cm soil temperature was about 15 ℃ in late April, and the temperature rose to 22.9 ℃ in mid-late May. It also took nearly 50 days for Gastrodia elata seeds to mature. There was a certain correlation between the length of flower stem growth cycle and the temperature rise.

In autumn, the flower stem of arrow hemp differentiates and forms, enters the reproductive growth stage, and must go through a low temperature stage to break dormancy. The dormancy period of arrow hemp is longer than that of white flax and rice flax, if it can not meet its requirements for low temperature, it can not bolt after planting, occasionally emerge seedlings, and the plant growth is not normal. In general, arrow hemp should be stored at a low temperature of 3 ℃ and 5 min for 2.5 months before it can successfully bolt, blossom and seed.

(3) effect of temperature on seed germination.

Gastrodia elata seeds can germinate between 15 ℃ and 28 ℃, but the most suitable temperature for germination is 25 ℃, and seed germination is restrained. It is a hot day in the producing area after sowing in June and July. The ground temperature of 25 ℃ is suitable for seed germination. Due to different geographical locations and climatic conditions, the maturity period of Gastrodia elata seeds is different, and the sowing time is early and late. There are also differences in the growth rate of protocorms. For example, Fubao Mountain in Lichuan City, Hubei Province, is 1550 meters above sea level. The seeds matured and sowed in mid-late July and germinated in late August. In mid-October, the ground temperature dropped to 13.2 ℃, the protocorm stopped growing, and the growing season was only 40 ℃ and 50 days.

Small hemp rice can be received, while at the experimental site of Gastrodia elata Research Institute at an altitude of 1050 meters in Ningqiang County, Shaanxi Province, the protocorm growing season after seed germination reaches 70m for 90 days, and finger-sized white flax can be obtained in the same year of sowing. There is a big difference in the size of white and rice and hemp harvested in the two places that year. In the new introduction area of Gastrodia elata in southern Shaanxi, after seed maturation and sowing in June, it is the seed germination season from late June to July, the ground temperature is more than 30 ℃, and the temperature is generally high, so cooling measures should be taken to improve seed germination rate and protocorm growth rate.

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