(Hu Wukuan)

Glycyrrhiza uralensis Fisch. is also known as sweet grass, sweet root, sweet licorice, etc. It is a perennial herb of the Leguminosae family. It is mainly produced in Xinjiang, Inner Mongolia, Gansu and other provinces and regions; in addition, it is also distributed in Qinghai, Shaanxi, Shanxi, Hebei and Northeast China. The roots and rhizomes are used as medicine. Contains glycyrrhizic acid (glycyrrhizin), glycyrrhetinic acid, liquiritigenin, isoliquiritigenin, liquiritin, licorice benzofuran, etc. Sweet in taste and neutral in nature. It has the functions of nourishing the spleen and replenishing qi, clearing away heat and detoxifying, relieving cough and phlegm, relieving anxiety and relieving pain, and reconciling various medicines. It is used for weak spleen and stomach, insufficient Qi, cough and asthma, carbuncle sores, acute abdominal cramps and pain, to alleviate the potency of drugs, and to detoxify drugs, etc. In the food industry and light industry, it can be used as an ingredient in cigarettes and candied foods. The quantity is large for internal use and export. Although the reserves are abundant, wild licorice resources have been severely damaged due to large-scale mining over the years. In recent years, Heilongjiang, Xinjiang, Shaanxi and other places have carried out domestic cultivation trials of licorice and achieved initial success.

The following licorice species are also purchased for medicinal purposes: G.glabra L., G.inflata Batal., G.aspera Pall., and Yellow Glycyrrhizae (G. .korshinskyi G.Hrig.), Yunnan Glycyrrhizae (G.yunnanensis Cheng, f.et L.K.Tai), G.squamulosa Franch., G.pallidiflora Maxim.

1. Morphological characteristics

Plant height is 50-150cm, and the whole plant is covered with white pubescence and glandular hairs. The rhizome is cylindrical and often runs horizontally; the main root is long and thick, with a reddish-brown to dark brown outer skin. Stem erect, lower part lignified. The leaves are alternate, odd-numbered pinnately compound leaves, with 5-17 leaflets, obovate, ovoid or broad elliptical, 2.5cm long and 2cm wide, with entire margin, both sides covered with glandular scales and white hairs, and the lower side is densely hairy. The racemes are axillary, the calyx is bell-shaped; the corolla is butterfly-shaped, purple-red or blue-purple, with 9+1 stamens, the ovary is sessile, and the upper part tapers into a short style. The pods are flat, mostly densely arranged in a globular shape, bent into a sickle shape or annular shape, brown, densely covered with spiny glandular hairs, and contain 6-8 seeds inside. Seeds are flat, oval, brown (Figure 14-60).

Figure 14-60 Licorice morphology diagram

1. Plant 2. Root

2. Biological characteristics

(1) Growth Development and its requirements for environmental conditions

The above-ground parts of licorice die in late autumn every year, and overwinter with roots and rhizomes in the soil. New buds grow from the rhizomes in early spring of the following year from March to April, and the buds grow upward for a long time. Fast, with long branches and leaves, luxuriant branches and leaves from May to June, flowers and fruits from June to July, and pods mature and fall to the ground in September. In the wild, seedlings propagated from seeds are rarely seen because the drought in the land is not conducive to seed germination. Licorice rhizomes have strong germination power and extend horizontally around the old plants tens of meters below the surface. One licorice plant can produce dozens of new plants in several years. Three years after planting, new plants can be seen growing 3-4m away from the mother plant.

Both its vertical rhizomes and horizontal rhizomes can grow roots. The depth of the root system varies depending on the soil quality and the depth of the groundwater level. It is generally in the range of 1-2m, and some are as deep as 10m or more, and even very deep. The root system absorbs groundwater to adapt to arid environmental conditions.

The place where licorice is distributed belongs to the continental climate zone, which is mainly characterized by drought, large temperature differences, severe cold in winter, with temperatures ranging from -40 to -30°C, and a permafrost layer of more than 1m deep. In summer, it is extremely hot. Open desert and semi-desert areas, strong light, little rain, and relative air humidity of 30-40%. Because licorice has the characteristics of cold resistance, drought resistance, light preference, and heat resistance, it grows well under the above ecological conditions. It is an indicator plant for calcareous soil and is also a plant with strong salt resistance. The soil salt content should not exceed about 0.2%.

(2) Accumulation dynamics of active ingredients

Licorice roots and rhizomes contain glycyrrhizin, glycyrrhizic acid, etc. According to research, the content of glycyrrhizin is higher in rhizomes than in roots, and in the bark of rhizomes than in the center column, with the highest content in rhizomes that have not yet been suberized. There is a kind of peeled licorice called pink grass. After peeling, the glycyrrhizin content is greatly reduced. The content of glycyrrhizic acid is higher in autumn, and the content of roots grown in 3-4 years is higher than that of roots grown in 1-2 years. The above information provides the suitable harvesting years and seasons for cultivated licorice.

3. Cultivation technology

(1) Selection of land and preparation

General soil can be grown, and slightly alkaline soil with a pH value of 8 is suitable. It must have good drainage. To facilitate irrigation and other operations, the land should be formed into small borders and basal fertilizer should be applied.

(2) Propagation

1. Seed propagation

In order to expand the area, seed propagation should be used. Licorice seeds collected from the wild have an insect-eaten rate of 60-80% and must be selected before sowing. Untreated seeds are partly hard and do not absorb water. The germination test was conducted at room temperature of 15-20°C. The germination rate of seeds one year after harvest was 45%, and the germination rate three years after harvest was 30%. In order to increase the germination rate, you can soak it in warm water at 60°C for several hours. In Heilongjiang, equal parts of broken glass slag and seeds are mixed and ground for half an hour, and the germination rate reaches about 85%; in the Soviet Union, seeds are soaked in concentrated sulfuric acid (concentrated sulfuric acid: water is 1:1.5). The germination rate was 60% after 30 minutes of treatment and 94% after 60 minutes.

It is divided into two types: live broadcast and seedling transplanting. Spring sowing is from March to April, and autumn sowing is from August to September. The drill sower opens a shallow trench with a row spacing of 50cm and a trench depth of 3cm. The seeds are evenly spread into the trench and then covered with soil. Hole sowers open holes at a distance of 10-15cm, sow 3-5 seeds in each hole, and use 2-3kg of seeds per acre. To keep the soil moist after sowing, cover the seedbed with grass. Water when the soil is dry. Seedlings will emerge two or three weeks after sowing.

Annual seedlings can be transplanted with row spacing of 50cm and plant spacing of 30cm, both in spring and autumn.

2. Rhizome propagation

Licorice has a strong ability to reproduce vegetatively. In spring and autumn, dig out the rhizomes and cut them into 5-10cm sections. Each section has 1-2 buds. Buried underground, the depth is about 20cm depending on the soil moisture, and it can grow into a new plant.

3. Propagation by divisions

Many new plants can sprout next to the old licorice plants, which can be dug out and planted in spring and autumn.

(3) Field management

After all the seedlings have emerged, the seedlings can be thinned once. When the seedlings are 5-6cm high, the seedlings should be fixed and the plant spacing should be 10-15cm. The seedlings are small in the first year, so weeding must be done diligently. When the plant grows up, new plants will grow from the rhizomes around it, which means it is not suitable for cultivating and weeding. At the end of autumn, the seedlings wither and turn yellow, and they overwinter naturally in the open field. Proper management after returning to green the following spring.

(4) Pests and diseases and their control

(1) Rust disease

[Uromyces glycyrrhizae (Rabenh.) Magn.] and (U.punctatus Schrot.)

Both species damage leaves and stems, forming yellow-brown summer spore piles, and later dark-brown teliospore piles, causing leaves to turn yellow and fall off in severe cases, affecting yields. Prevention and control methods: Apply more phosphorus and potassium fertilizers to improve plant disease resistance; pay attention to ventilation and light transmission, and the plants should not be too dense; spray 1000 times of Fenxinin 1000 times liquid for prevention and control in the early stage of the disease.

(2) Gray leaf spot disease

(Cercospora astragali Woron)

It damages the leaves and forms nearly round brown lesions with gray in the middle. Clear the garden in winter and dispose of the remains; spray Bordeaux mixture or chlorothalonil for control in the early stages of the disease.

(3) Powdery mildew

(Erysiphe polygoni DC.)

The front of the leaves is covered with white powder, which will cause the leaves to turn yellow in the later stage, affecting growth and yield. For prevention and treatment methods, see Astragalus powdery mildew.

(4) Licorice seed wasp

(Bruchophagus sp.)

It is a broad-shouldered wasp. Adults lay eggs on the seed coat of green fruits. After hatching, the larvae eat the seeds and pupate within the seed. After the adults emerge, they bite through the seed coat and escape. The damaged seeds are eaten away, leaving small round emergence holes on the seed coat and pods. This insect has a great impact on seed yield. For prevention and control methods, see Astragalus seed wasp.

(5) Aphids

(Aphis craccivora Koch)

Damage twigs, leaves, flowers and fruits. Adults and nymphs pierce and suck sap. In severe cases, the leaves may turn yellow and fall off, affecting fruit set and commercial yield. For prevention and control methods, please refer to Astragalus Aphid Control 4. Harvesting and Processing

(1) Seed Saving

Seeds are collected from wild licorice. When the seeds mature from July to August, they are cut, dried and threshed. . Licorice grown at home will bloom and bear fruit in the fourth year if it is sown by direct seeding, and if it is propagated by rhizomes and ramets, it will bloom and bear fruit in the same year.

(2) Harvesting

Home-grown licorice can be harvested in the fourth year of direct seeding, the second to third year of transplanting, and the third year of rhizomes and ramets propagation. The seasonal habit of harvesting licorice is in late autumn, early winter and before it germinates in spring. According to experiments, it is better to harvest licorice in autumn because it is hard and high in content.

(3) Processing

Dig out the licorice, remove the soil, cut it into different specifications, dry and package it in the sun, with a dry to fresh ratio of 1:2-2.5.

Process the cut licorice scraps and boil them into licorice paste. The licorice extract contains not less than 20% glycyrrhizic acid, and the licorice liquid extract contains not less than 7% glycyrrhizic acid.

(4) Specifications

According to the standards promulgated by the Ministry of Health, it is divided into the following grades:

Xinjiang licorice is divided into the following grades:

Session - about 10cm long and 0.6-3.5cm thick.

Original grass - regardless of length, thickness shall not exceed 3.5cm.

The above-mentioned various specifications of licorice are required to be dry, free of impurities, insects, and mildew.

Store in a dry and cool place, do not get wet.

For medicinal purposes, cut into slices and use them raw or roasted with honey. According to research, 0.2-0.5cm thick licorice powder has a higher content of glycyrrhizic acid than the active ingredient glycyrrhizic acid when sliced ??and fried. It is recommended to grind licorice into coarse powder and use it as medicine.