ginkgo

ginkgo

synonym

White fruit trees generally refer to Ginkgo biloba (deciduous trees of ginkgo family)

This entry is compiled and applied by "popular science China" Science Encyclopedia

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Ginkgo biloba (scientific name: < I Ginkgo biloba < / I L.) is a plant of ginkgo family and genus. Tree, up to 40 meters high, diameter at breast height up to 4 meters; young tree bark shallow longitudinal crack, big tree bark is gray brown, deep longitudinal crack, rough; young and middle-aged crown conical, old wide oval. Leaves fan-shaped, long petiole, light green, glabrous, with many forked parallel veinlets, 5-8 cm wide at the top, often undulate notched on the short branch, often 2-lobed on the long branch, and broadly cuneate at the base. Strobils dioecious, unisexual, clustered in axils of scalelike leaves at the top of short branches; male strobils catkin like, pendulous. Seeds with long stalks, pendulous, often elliptic, long obovate, ovoid or nearly spherical.

Ginkgo biloba is a rare species left in Mesozoic era. It is a special product of China. Only in Tianmu Mountain of Zhejiang Province, there are wild trees. It grows vigorously in the natural forest of 500-1000 meters above sea level, acidic (pH value 5-5.5) yellow soil and good drainage zone. It often grows together with Cryptomeria fortunei, Torreya grandis, blueberry and other coniferous and broad-leaved trees. It is cultivated in gardens of Korea, Japan, Europe and America.

Ginkgo biloba is a fast-growing and precious timber species. Its sapwood is light yellow and heartwood is light yellow brown. It has fine structure, light and soft quality, rich elasticity, easy processing and luster. Its specific gravity is 0.45-0.48. It is not easy to crack and flex. It is an excellent timber for architecture, furniture, interior decoration, carving, drawing board, etc. The seeds are used for food and medicine. The leaves can be used as medicine, insecticide and fertilizer. The fleshy exotesta of the seed is poisonous and contains acid, alcohol and phenol. The bark contains tannins. Ginkgo has a beautiful shape. Its leaves are green in spring and summer and yellow in autumn. It can be used as garden tree and street tree.

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morphological character

Tree, up to 40 meters high, diameter at breast height up to 4 meters; bark of young tree is shallow longitudinal crack, bark of big tree is gray brown, deep longitudinal crack, rough; crown of young and middle-aged tree is cone-shaped, old tree is wide ovate; branches are nearly whorled, oblique upward extension (big branches of female plant are often more developed than male plant); annual long branches are light brown yellow, gray above biennial, with fine longitudinal cracks; short branches are densely covered with leaf marks, black gray The winter buds are yellowish brown, usually oval, with blunt apex.

The leaves are fan-shaped, long petiole, light green, glabrous, with many forked parallel veinlets, 5-8 cm wide at the top, often with wavy notches on the short branches, 2-lobed on the long branches, wide cuneate at the base, 3-10 (mostly 5-8) cm long at the petiole. The leaves on the saplings and sprouting branches are often more deeply lobed (the leaves are 13 cm long and 15 cm wide), and sometimes the lobes split again (this is similar to the leaves of more primitive fossil species) The leaves are scattered spirally on the annual branches, 3-8 in clusters on the short branches, and turn yellow before falling leaves in autumn.

Cones dioecious, unisexual, in the axils of scaly leaves at the top of short branches, in clusters; male cones catkin like, drooping, stamens loosely arranged, with short stalks, anthers often 2, long elliptic, anther locules longitudinally split, connective not hairy; female cones with long stalks, stalks often bifurcated, sparse 3-5 forked or not forked, each forked terminal disc-shaped ovule, usually only one ovule The ovules at the two forks develop into seeds, which are pollinated by wind.

The seed is long stemmed, pendulous, usually elliptic, long obovate, ovoid or nearly spherical, 2.5-3.5 cm long and 2 cm in diameter. The outer testa is fleshy, yellow or orange yellow when ripe, with white powder outside and stinky leaves. The middle testa is white, bony, with 2-3 longitudinal ridges. The inner testa is membranous, reddish brown. The endosperm is fleshy, sweet and slightly bitter. The cotyledons are 2 and 3, which are not unearthed when germinating, and the first seed is fresh Leaves 2-5, broad strip, ca. 5 mm long, ca. 2 mm wide, apex slightly concave, 4th or 5th leaf fan-shaped, apex with a deep fissure and irregular wavy notch, petiole 0.9-2.5 cm long; taproot.

Cultivar

In the process of long-term cultivation of Ginkgo biloba in China, many excellent varieties with large seeds and good kernel quality have been bred to produce dried fruits. The main cultivated varieties are as follows:

Growth environment

Ginkgo biloba grows vigorously in the natural forest with 500-1000 meters above sea level, acidic (pH 5-5.5) yellow soil and good drainage area, and often mixed with coniferous and broad-leaved trees such as Cryptomeria fortunei, Torreya grandis and blueberry. Ginkgo biloba is a light loving tree species with deep roots and wide adaptability to climate and soil. It can grow slowly or poorly in areas with high temperature and rainy, little rainfall and cold winter. It can grow in acidic soil (pH 4.5), calcareous soil (pH 8) and neutral soil, but it is not tolerant to saline alkali soil and over wet soil. The best growing areas live peacefully in the areas where the altitude is less than 1000 meters (Yunnan 1500-2000 meters), the climate is warm and humid, the annual precipitation is 700-1500 mm, the soil layer is deep, fertile and humid, and the drainage is good. They do not live late or grow poorly in the places where the soil is barren and dry, and the rocky hillside is excessively humid.

Distribution range

Ginkgo biloba is a rare species left in Mesozoic era. It is a special product of China. There are only wild trees in Tianmu Mountain of Zhejiang Province. Ginkgo biloba is cultivated in a wide range of areas: Shenyang in the north, Guangzhou in the south, 40-1000 meters above sea level in East China in the East, and below 2000 meters above sea level in Guizhou and Western Yunnan (Tengchong) in the southwest. It is mainly cultivated in Pizhou City of Jiangsu Province for the purpose of seed production or as a garden tree species. It is cultivated in gardens of Korea, Japan, Europe and America.

Growth habit

The initial growth of Ginkgo biloba is longer and the sprouting ability is stronger. Ginkgo biloba trees are divided into male and female plants. Male plants do not bear fruit, while female plants usually begin to bear fruit after 20 years of growth. Ginkgo biloba trees usually begin to sprout and spread leaves from March to April, bloom from April to may, and mature seeds from September to October, and leave leaves after October.

In the cultivation area, seedling, stem transplanting seedling or root tillering seedling are commonly used for grafting, which can blossom and bear seeds at the age of 8-10 years in advance (seedling usually begins to bear seeds after 20 years). Ginkgo biloba cultivated in various places has hundreds of years or more old trees.

Methods of reproduction

Ginkgo biloba can be propagated sexually and asexually by sowing, hardwood cutting and tillering. In order to obtain seeds, dioecious Ginkgo biloba can also be grafted on the branches of female plants by budding, which can make the plants blossom and bear fruit in advance and propagate seedlings in large quantities.

sow

When Ginkgo biloba leaves enter the reproductive growth stage, artificial or natural pollination can be used to make it bear more fruits. The seeds were harvested and dried from September to October, stored in a ventilated place with gauze bags, and sowed and propagated in April to May of the next year when the temperature was stable at about 20 ℃. When sowing, the seedbed should be deeply raked, leveled as a border, and the furrow depth should be 4-6cm with the row spacing of 30-40cm, and then the seeds should be sown in the soil ditch one by one with the spacing of 6-8cm. After sowing, water was poured once and covered with fine soil or sandy soil. In order to maintain moisture and good ventilation, the seedbed can be covered with a layer of straw. After the seedlings are unearthed, remove the straw, and transplant before the sprouts germinate in the next spring to cultivate strong seedlings for garden and courtyard greening.

cuttage

Propagation of Ginkgo biloba by cutting is a common method in horticultural cultivation. This method is easy to operate and the technology is not complicated. It can be tried out in general families.

The cutting time of Ginkgo should be in early spring or late autumn. During the operation, select the strong branches that have been growing for one year, take out the middle and upper parts, and cut them into 10-15cm segments for cutting. In order to promote the early germination of new roots, the base of cuttings can be soaked in 0.2/10000-0.8/10000 aqueous solution of indoleacetic acid or naphthylacetic acid for 12-14 hours, and then inserted into the seedbed made of fine sand or vermiculite. When cutting, most of the cuttings should be inserted into the soil, leaving only one bud node on the ground, and its length should not exceed 3cm at most. The cuttings were watered once after cutting.

In order to maintain the ground temperature, bamboo can be used to build arch on the seedbed, covered with plastic film to strengthen water management and maintain the relative humidity of the space. If the light is strong and the temperature is too high, pay attention to ventilation. When the cuttings germinate new buds, the film should be removed to increase the light intensity and promote the robust growth of seedlings. Generally, transplanting can be carried out in the early spring of the next year. Expand the spacing between plants and rows to make the seedlings grow healthily.

Ramet

After several years of Ginkgo biloba growth, tiller buds sometimes germinate at the base of the plant. The grower can cut the cortex at the base of the bud in spring and backwater the soil to make the base take root. After defoliation in autumn, the tiller buds of underground roots can be cut off from the mother plant in the middle and late September in the Yangtze River Basin and its south.

The root system should be protected when cutting. The incision can be disinfected with sulfur yellow powder or 1% copper sulfate solution. When cultivating, you can erect or slant according to your own needs. However, the root system should be natural, not too bent root injury, planted in slightly acidic or neutral soil

Chinese PinYin : Bai Guo Shu