Why is Angelica bolting ahead of time?

Why is Angelica bolting ahead of time? Please introduce the reasons 1, the reason for early bolting of Angelica 1.1 the seeds are too full, or the seedlings are raised with seeds (commonly known as gunpowder seeds, [flower] seeds or fire seeds), which are easy to bolt in advance after transplanting. According to the experience of drug farmers, Angelica seedlings have very strict requirements on seeds. Different seedlings are produced with different seeds, and seeds with head ear, mature seeds, wax-ripe seeds, and some drug farmers even mix the seeds with bolting plants in advance and sow them after sowing. And in the case of the same cultivation conditions, the bolting period of (flower) seedlings is 10 min 15 days earlier than that of leaving seeds, and the bolting rate is 30% and 40% higher. Because mature seeds, (flower) seeds and head ear seeds are strongly developed seeds, which are the important basis for forming large and strong seedlings, and have the conditions for stage development, which speeds up the speed of qualitative change in vernalization and light stages, so the bolting rate is high. 1.2 if the seedling is raised too early, the seedling age is too long, the seedling root is too large, and the overweight and sufficient nutrition are easy to develop into bolting plants ahead of time. The growth period of Angelica sinensis in seedling stage is generally 90ml 110 days, and the fresh weight of 100 roots is 40ml 70g. Sowing and raising seedlings are generally from mid-June to mid-July, that is, between the Summer Solstice and Greater Heat, and sowing is more suitable. Generally, from the first to the middle of October, that is, when the temperature drops to 0 ℃ when Cold Dew and Frosts Descent, the seedlings gradually enter the dormant period and can be raised and stored for transplanting in the coming year. Such as raising seedlings too late, the growth period is too short, insufficient nutrition, tender seedlings, easy to rot, not easy to store over the winter. Therefore, after mastering the appropriate sowing time, sow a few days later. 1.3 Seedling size is related to early bolting, large seedlings, forked seedlings, old seedlings and overwintering seedlings in the field, seedlings that rise too late all have the conditions to accept vernalization stage and low temperature in winter, so they are easy to bolt in advance. When transplanting, the bolting rate of seedlings suitable for seedling age is very low, while that of large seedlings is high. For this reason, drug farmers in Minxian County mostly use seedlings with a diameter of less than 0.50 cm. However, the seedling size should correspond to the seedling age, if the seedling weight is very small, but the seedling age is old, the bolting rate of the seedling is still very high; on the contrary, the large seedling with large seedling age seldom bolts. 1.4 the cultivation conditions also affect the adverse external conditions such as bolting, drought, thinness, lack of fertilizer, low mountains, shady slopes, flat land planting, early planting, serious diseases and insect pests, which are easy to cause Angelica plants to accelerate the development of the two stages of transition and bolting in advance. Because there are obvious stages in the process of ontogeny of Angelica sinensis, when it changes from vegetative growth to reproductive growth, that is, bolting and flowering. Must go through the vernalization stage and the light stage. The main development condition of vernalization stage is low temperature of 5 ℃ in Murray, and the main development condition of light stage is long sunshine of more than 12 hours. When the environmental conditions such as water, fertilizer and temperature are superior, the vegetative growth of the plant is dominant, and the development process is delayed accordingly; when the environmental conditions are disadvantageous to its growth, the plant turns to the reproductive growth stage early, bolting, blooming and fruiting ahead of time. This is a kind of adaptability of plants to environmental conditions. 1.5 the sowing density also affects the sowing rate of bolting Angelica sinensis in advance. Generally, the sowing rate of Angelica sinensis is 5kg, sometimes up to 7.50kg. If the sowing rate is too small, the emergence of seedlings is large and sparse, it is easy to grow into large seedlings and forked seedlings, and the number of seedlings is small, and the rate of bolting ahead of time is high. If the sowing rate is too large, the emergence of seedlings is too dense, although there are many mature seedlings, but the proportion of seedlings that can not be used is high, most of them can not meet the requirements of transplanting seedlings, and it is not easy to survive after planting, or survive but return to green slowly. Therefore, the sowing rate should be adjusted according to the germination rate. 2. Prevention and control of early bolting of Angelica sinensis according to the reasons of early bolting of Angelica sinensis, targeted measures can be taken to control it. The main measures are as follows: 2.1 starting with stage development, it is the main condition to control stage qualitative change. As long as we control the normal progress of qualitative change in vernalization stage or light stage, we can control bolting in advance. It is much easier to control vernalization stage than to control light stage in production. Because the vernalization stage can be controlled during the period of seedling storage in winter, the seedlings are more concentrated and easy to carry out. That is, the seedlings are first sterilized, the humidity of the seedlings is controlled at 60% Murray 65%, and the temperature is preferably at-7-10 ℃. 2.2 starting from the nutritional conditions, control the seedling size according to the fat and thin soil fertility, apply less or more phosphorus and potassium fertilizer, and control the seedling diameter at 0.20 Mel 0.50 cm. 2.3 Comprehensive measures should be taken to control the three production links of seedling storage, seed retention and seedling raising. When keeping seeds, the remaining plants will pick off the main stem at the early stage of moss, so as to promote the development of a large number of basal lateral branches and form a large number of stems with equal growth, so as to reduce the individual differences between seeds and make the degree of seed development more moderate and homogeneous. on the other hand, it is necessary to control the maturity of seeds and select mature milky seeds by stages. The temperature of seedling storage was controlled at-7 Mel 10 ℃. At the same time, improving the conditions of raising seedlings, making the weight of one hundred mu 40 ~ 70g, the diameter of seedlings 0.20 ~ 0.50cm, or changing the cultivation system, direct seeding in autumn, winter or spring, and transplanting after raising seedlings in solar greenhouse can prevent Angelica sinensis from bolting in advance. 2.4 advocate keeping seeds and raising seedlings because at present, Chinese angelica seedlings are still raised mainly in wasteland, while some Sichuan drug farmers can only buy seedlings from the market, or seed seedlings, but the origin of the seeds and seedlings purchased in the market is unknown, so it is impossible to guarantee their low bolting rate, so it is best to keep seeds and raise seedlings every year. If you buy from the market, it is best to contact acquaintances to ensure that they are seedlings and seeds with low bolting rate. 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