Longan is a plant of the genus Longan in the Sapindus family. Evergreen tree, usually more than 10 meters high; branchlets are stout, puberulent, and scattered with pale lenticels. The petiole is 15-30 cm or longer; 4-5 pairs of leaflets, thinly leathery, oblong-elliptic to oblong-lanceolate, often asymmetrical on both sides; petiole length usually does not exceed 5 mm. The inflorescence is large and multi-branched; the pedicel is short; the sepals are nearly leathery, triangular-ovate; the petals are milky white, lanceolate, nearly as long as the sepals, only puberulent on the outside; the filaments are short bristles. The fruit is nearly spherical, usually yellowish-brown or sometimes grayish-yellow, slightly rough on the outside, or rarely with small convex tumors. The seeds of longan are dark brown, shiny, and all are wrapped in fleshy arils. Flowering in spring and summer, fruiting in summer.
Longan is native to southern China, distributed in Fujian, Taiwan, Hainan, Guangdong, Guangxi, Yunnan, Guizhou, Sichuan and other provinces, and mainly produced in Fujian, Taiwan, and Guangxi. It grows in the south subtropical region, likes warm and humid climate, can tolerate short-term frost, and will not freeze to death in a short period under low-temperature conditions of 0-4℃.
The economic use of longan is mainly as a fruit. Because its aril is rich in vitamins and phosphorus, it is beneficial to the spleen and brain, so it is also used as medicine; the seeds contain starch, after proper treatment, they can be used for wine; the wood is firm and heavy, Dark reddish-brown, resistant to water and humidity, is an excellent material for shipbuilding, furniture, craftsmanship, etc.
Longan morphological characteristics
Longan is an evergreen tree, usually more than 10 meters in height, with large trees up to 40 meters in height and 1 meter in diameter at breast height with buttresses in between. The branchlets are thick, puberulent, and scattered with pale lenticels. The petiole is 15-30 cm or longer. Longan has 4-5 pairs of small leaves, rarely 3 or 6, thinly leathery, oblong-elliptic to oblong-lanceolate, often asymmetrical on both sides, 6-15 cm long, 2.5-5 cm wide, short tip Pointy, sometimes slightly blunt head, extremely asymmetrical at base, broad wedge-shaped to truncated on the upper side, almost parallel to the leaf axis, narrow wedge-pointed underside, dark green on the ventral surface, shiny, pinkish green on the back, hairless on both sides. Longan has 12-15 pairs of lateral veins, bulging only on the back; petiole length is usually no more than 5 mm.
The inflorescence of longan is large, multi-branched, terminal and near branch axillary, densely covered with stellate hairs; pedicel is short; sepals are nearly leathery, triangular-ovate, about 2.5 mm in length, both sides are covered with brown and yellow hairs and bunches Stellate hairs; petals milky white, lanceolate, nearly as long as sepals, only puberulent on the outside; filaments short bristles. The fruit is nearly spherical, 1.2-2.5 cm in diameter, usually yellowish-brown or sometimes grayish-yellow, slightly rough on the outside, or rarely with small convex tumors; the seeds are dark brown, bright, and all are wrapped in fleshy arils. The flowering period of the longan is between spring and summer, and the fruit period is summer.
Longan growth habit and growing environment and distribution
Longan grows in the south subtropical region. It likes a warm and humid climate and can tolerate short-term frost. It will not freeze to death in the short term under low-temperature conditions of 0-4°C. The annual average temperature in the main producing areas of Putian, Fujian, China is 20-22℃, and the annual average temperature in Sichuan producing areas is about 18℃; the short-term low temperature in winter is conducive to the differentiation and formation of longan flower buds.
Longan producing areas generally have an annual rainfall of 1200-1600 mm.
Longan is a positive tree species and requires sufficient sunlight.
Longan is very adaptable to the soil. In the main production area of Putian, Fujian, China, red sandy soil and clay can grow. As long as the topsoil layer is deep and the drainage is good, almost all kinds of soil can adapt. Sandy loam is the best, followed by sandy red soil and clay. The soil pH is 5.4-6.5 to grow best, and alkaline soil is not suitable for planting.
Longan is native to southern China, distributed in Fujian, Taiwan, Hainan, Guangdong, Guangxi, Yunnan, Guizhou, Sichuan and other provinces (regions), mainly produced in Fujian, Taiwan, and Guangxi. It is also often cultivated in southern and southeastern Asia.
Longan efficacy and role
Medicinal use: The fruit is rich in nutrition and is a valuable advanced tonic. Longan has a sweet taste and has the functions of nourishing the heart and spleen, nourishing blood and calming the nerves. Indications include deficiency of Qi and blood, restless heart palpitations, forgetfulness and insomnia, blood deficiency and chlorosis, as well as middle-aged and elderly weakness, hypertension, hyperlipidemia and coronary heart disease.
Economy: Longan is mainly used as a fruit for economic purposes. The seeds contain starch and can be used for wine after proper treatment. The wood of longan is solid, heavy, dark reddish-brown, water-resistant, and is an excellent material for shipbuilding, furniture, and craftsmanship.
Longan propagation methods include grafting, high pressure and seedling. Due to the large variation of seedlings cultivated by seeds and the uneven quality, it takes 15-20 years to bloom and bear fruit after planting. The economic benefits are poor, and seedlings are generally not used in production. In order to ensure the excellent characteristics of the variety and put it into production as soon as possible, grafting and high-pressure seedling breeding are more common in production.
There are many methods of grafting, including sprout attachment, tongue splicing, abdominal splicing, insertion splicing, cutting splicing, docking and sprout anvil grafting. The methods of sticking buds, tongues, and sprouts with anvils are simple and easy, and the survival rate is high. In addition, some areas have also adopted high grafting to transform seed trees with small fruits, poor quality, and low yields to improve economic benefits. The embedded method is generally used. Grafting seedling breeding has a high propagation coefficient, can maintain the characteristics of famous and high-quality varieties, early fruit, high yield, developed root system, adapt to mountain cultivation, strong typhoon resistance, and suitable for development and promotion of coastal hilly land.
Generally, from late March to early April when the longan sap is flowing, choose the mature plants with no pests and diseases, strong growth, and good quality. The oblique branches and stems are about 4 cm. The base of the branches and stems is peeled in a ring of about 2.5 cm. -7 days later, wrap the girdle with two specially made pots or bamboo tubes with holes and tie them with ropes, then fill the bowl or bamboo with viscous slurry to evenly wrap the girdle around and keep it moist. After 3-4 months, when the new roots are full of the bowl, they can be sawn off and separated, transplanted in the shade and cultivated for 1-2 years before being planted in the nursery. It can also be planted directly with good management conditions. In addition, there are also moss and straw dipped in mud to directly wrap the girdling area, and then wrap it with a plastic sheet for heat preservation. New roots can grow after 5-6 weeks. It can be cut off and transplanted. The materials can be taken locally, which is more convenient. The high-pressure seedling raising method is simple, can maintain the excellent quality of famous, special and high-quality varieties, put into production early, and has a short crown, which is convenient for operation and management. But its reproduction coefficient is low, the root system is shallow, the wind resistance is poor, and the drought resistance of uphill cultivation is also weak, so it is suitable for cultivation under the hill and on the sides.