Rheum tanguticum, also known as Rheum calyx.
Tall perennial herb, about 2 meters high, similar to previous species. Stems glabrous or hairy. Rhizome leaves are slightly round or broadly heart-shaped, with a diameter of 40-70 cm, 3-7 palmately parted, long and narrow lobes, often feathery and shallow, with a sharp apex and a heart-shaped base; Cauline leaves are smaller and stems are shorter. Panicle is large, mostly dark purple when young, but also green and white, with tight branches and straight branchlets; Flowers are small and have long pedicels; Perianth 6, 2 rounds; Stamens are generally 9; Ovary triangular, style 3. Achenes are triangular, winged, rounded or slightly concave at the top and heart-shaped at the base. The flowering period is from June to July. The fruiting period is from July to September.
Born in a humid place on the edge of a mountain forest. Distributed in Qinghai, Gansu and Sichuan. Tibet and other places.
Medicinal rhubarb, also known as Nandahuang.
Tall perennial herb, about 1.5m high. Stems erect, sparsely pubescent, with dense nodes. Long petiole with roots, round to ovoid leaves, 40-70 cm in diameter, palmately lobed, or only notched and coarsely serrated, with acute apex and heart-shaped base, usually 5 main veins, basal, hairless above, or sparse papillae near the state veins, with hairs below, mostly distributed in veins and leaf margins; Cauline leaves are small and stems are short; Leaf sheaths are solitary, sparsely short-haired, and cracked at the base. Panicle, large, many branches, small flowers, 3 ~ 4 mm in diameter, 4 ~ 10 flower cluster; Perianth 6, light green or yellowish white, 2-whorled, inner whorl oblong, about 2 mm long, apex rounded, edge irregular, outer whorl slightly shorter; Stamens 9, not exserted; Ovary triangular, flowers on 3. Achene is triangular, winged, about 8 ~ 10 mm long and 6 ~ 9 mm wide, with a concave top and red color. The flowering and fruiting period is June-July. Most of them grow in mountainous areas with good drainage. Distributed in Hubei, Sichuan, Yunnan, Guizhou and other places.
The stems or seedlings of the above plants are collectively called rhubarb stems and can also be used as medicine.
morphological character
Rhubarb is a perennial herb of Polygonaceae. Its roots are fleshy, lignified, fork-free, radish-shaped, and some have several forks, showing the shape of a bull's head. The stem is erect, unbranched, 90- 120 cm high, hollow, with longitudinal grooves and pubescence. Rhizome leaves are large, suborbicular and palmately divided. Inflorescence conical, closely branched, branchlets straight, several clustered at each node. Flowers are small, clustered, green and white or deep purple. Achene is red, triangular, rectangular, with 3 edges, rounded or slightly concave at the top and heart-shaped at the base.
Growth habit
Sexual preference for cold climate, cold tolerance and avoidance of high temperature. Wild in the mountainous areas with an altitude of about 2000 meters in the northwest and southwest of China; The family is planted in the area above 1400 meters. Climatic conditions: the lowest temperature in winter should be above-10℃, the temperature in summer should not exceed 30℃, the frost-free period is 50- 180 days, and the annual rainfall is 55-1000 mm. The requirements for soil are strict. Generally, it is best to use soil or sandy soil with deep soil layer, rich humus and good drainage. Planting in sticky and acidic soil will cause poor growth of rhizomes and affect yield. Plots with poor drainage and high groundwater level are not suitable for planting. Continuous cropping of rhubarb should be avoided and replanted after 4-5 years. It is suitable to rotate with leguminous and Gramineae crops, or take Codonopsis pilosula and Coptis chinensis as the previous crops.
Rhubarb seeds germinate easily. At the temperature of 15-25℃, the germination rate can reach more than 85%, and the seed life is l-2 years.
Planting techniques of rhubarb
1. Land selection and preparation
Rhubarb is a deep-rooted plant, the taproot can penetrate 30-45 cm into the soil layer, so it is better to choose loose and well-drained sandy sloping land. After harvesting the previous crops such as corn and potato, combine deep ploughing and apply sufficient base fertilizer, and apply 4,000-5,000 kg of manure per mu. In poor soil, the amount of fertilizer can be increased.
2. Breeding method
Mainly by seeds, but also by buds. Seed propagation is divided into direct seeding and seedling transplanting.
(1) The live broadcast is conducted in early autumn or early spring. For live broadcast, the row spacing is 70cm×60cm and the hole depth is about 3 cm. Sow 5-6 seeds in each hole and cover it with soil for about 2 cm. The amount of seeds used per mu is 2-2.5 kg.
(2) Seeding and transplanting In order to save seeds and improve land utilization, or in areas where direct seeding is not suitable in spring drought, seeding and transplanting are often adopted. The method is to make a high ridge with a width of 1.2 m and a length of 2 1 m on the whole land, with drainage ditches on all sides. Seeding horizontally in the border with row spacing of12cm and depth of 5cm. Spread the seeds evenly into the ditch, cover them with soil for 2-3 cm, and then cover them with a layer of grass. Expose the grass after germination and digging holes. Pay attention to weeding, and apply some diluted human excrement and urine topdressing in May and June. In winter, in late June, 3-5 cm of soil was cultivated on rhubarb seedlings in 438+1October to prevent the seedlings from being damaged, and the seedlings were transplanted in the next year.
Transplanting in mid-April (Grain Rain) or late August (summer) in the second year of seedling raising. After digging out the seedlings, cut off the lateral roots of the seedlings, plant the whole plant in time, with the row spacing of 60 cm, dig holes 15-30 cm deep, each hole 1 plant, cover the soil, bury the reed head, and compact the soil to make the roots and soil closely combine.
When transplanting, "curved root planting" can be adopted, that is, when planting, the root tip of the seedling is bent upward into an L shape, which can greatly reduce the bolting rate of the plant.
(3) Propagation of sub-buds When harvesting rhubarb, pick and plant robust and large sub-buds sprouting from the roots of the mother plant. Buds that are too small can be planted in seedbeds and then planted in the following autumn. In order to prevent the wound from rotting, plant ash can be applied to the wound when planting.
3. Tian Tuan management
(1) In the first year of intertillage weeding, rhubarb seedlings are small and weeds are easy to grow. Weeding often combined with loosening soil, planting soybeans and corn between rows to inhibit the growth of weeds. Weed and loosen the soil in the second year to the third year, early May and mid-July, and cultivate more soil at the roots.
(2) Fertilized rhubarb is a fertilizer-loving plant, and it needs topdressing 2-3 times a year besides base fertilizer. In June of the first year, 50 kg of cake fertilizer and 0/0-20 kg of calcium superphosphate/kloc were used. In the second year, topdressing was conducted twice. In May and June, human excrement and urine, or 20-30 kg of calcium superphosphate and 0/0-20 kg of potassium chloride/kloc were applied to the furrows between rows, and then covered with soil and watered.
(3) After planting rhubarb, bolting and flowering began in the second year. Except for planting, all other plants should be plucked, and bolting should be carried out on sunny days.
4. Pest control
The main disease is root rot, which mostly occurs in the rainy season from August to September, or when it is hot and humid, and mostly occurs in the year or the year before the rhubarb harvest. The top of the root began to turn black and rot, and the leaves turned yellow at the same time, even died. The prevention method is to pay attention to the elimination of stagnant water and loosen the soil in time. After dressing, melt the soil of the wound or disinfect it with quicklime water. Pull out the diseased plants as soon as possible after the onset of the disease, collect and burn the litter in autumn, and reduce the source of germs. Insect pests are aphids, which are more serious in June and July. dimethoate EC can be sprayed 2000 times. Rodents can be captured or culled manually.
5. Harvest and processing
After planting rhubarb for 2-3 years, harvest it in September-65438+1October when the aboveground parts wither. When harvesting, cut off the above-ground parts first, dig out all the roots and rhizomes, and shake off the soil carefully. Extra-large roots can be cut into several pieces, and small ones can be cut into pieces and dried or dried. After drying, put it into a wooden box or a drug collider for collision, and knock off the rough epidermis to show yellow color. About 400 Jin of dry goods can be collected per mu.