Ginkgo

The first scientific mention of ginkgo was made by Engelbert Kempfer in Amoenitatum exoticarum (1712) ^[2] . He mistakenly recorded it as Ginkgo, Itsjo instead of Ginkjo, Itsjo . Later, Karl Linney repeated this mistake in Mantissa plantarum II (1771) ^[3] , and the name Ginkgo was assigned to the tree.

The species epithet bíloba in Latin means “bilobate”, because most of the leaves are divided into two halves.

In Japan, the name of the ginkgo tree ( Jap. 銀杏 ) is pronounced ityo: - this pronunciation comes from the Chinese phrase “duck legs” ( Chinese trad. 鴨 脚 , ex. 鸭 脚 , pinyin : yājiǎo ), since the leaves of the tree resemble them in shape ^[4] . The hieroglyphic name for the seed means "silver apricot" and is read as "ginnan."

Ginkgo is considered a "living fossil" and is a sister group in relation to gymnosperms , although it is very different from conifers . It is believed that the ginkgs are the immediate descendants of one of the groups of ancient seed ferns , or pteridosperms ^{[5] [6]} .

Ginkgo fossils arose at the beginning of the late Permian period , and reached their maximum diversity in the middle of the Jurassic period , when at least 15 different genera of Ginkgoae were growing ^[7] .

Ginkgoaceae plants were widely distributed on Earth in the Mesozoic era . In the temperate polar forests of Siberia in the Jurassic and Early Cretaceous, the Ginkgo were so common that they are found in most sediments of that time, in the autumn the land was often covered with a continuous carpet of Ginkgo leaves ^[8] , like modern carpets from maple and linden leaves in the European part of the former USSR. At the end of the Jurassic period approx. 150 million liters n in Laurasia and Gondwana, the ginkgoids were distributed almost everywhere. On the border of the Early and Late Cretaceous approx. 100 million liters n most of the ginkgo genera die out, and from the second half of the Cretaceous, almost one ginkgo genus remains. 7 million liters n ginkgo disappeared in North America, and 2.5 million liters. n disappeared in Europe ^[9] .

Previously, Mount Tianmu (Tianmushan), located in the urban district of Hangzhou , which is located near Shanghai, was considered the modern homeland of the Ginkgo bilobate ^[12] . Genetic studies indicated the cultural origin of this population. It is believed that Buddhist monks planted trees near their temples ^[11] . New plants sprang from them, a forest was formed, in which Chinese partisans hid during the Second World War ^[13] .

Scientists agreed that Ginkgo survived the Pleistocene glaciations on the territory of the Yunnan-Guizhou plateau , in more detail, in the Dalou mountains (Daloushan), which rose on the border of Guizhou province and Chongqing urban district ^[14] . Most haplotypes are concentrated there, there are several endemic ones ^[11] .

In Daloushan, a living fossil grows in three types of forests that have a partial floristic similarity with the Pleistocene and Pliocene ginkgo fossils of southwestern Japan ^{[14] [15]} .

• Ginkgo forests dominated by ginkgo bilobate.
• Mixed forests of ginkgo and weeping cypress .
• Complex mixed forests of ginkgo, cunningamia, weeping cypress, liquidambara formosa and evergreen oak ( Cyclobalanopsis glauca ).

In all three forest types, yew Wallich and the evergreen species of linder ( Lindera megaphylla ) are found ^[15] . An unusual tree from the madder family, Emmenopterys henryi, was found in ginkgo-containing forests ^[14] . Some species of monkeys, for example, the Tonkin Gulman (Langur Francois), have chosen the same places as Ginkgo ^[10] .

Ginkgo prefers valleys, crevices between rocks and the lower parts of mountain slopes. It settles on limestone outcrops, survives on thin soils ^[14] . Altitude range in the mountains: 500-1500 m ^[16] . The climate has subtropical similarities and monsoon differences from Sochi ^[14] . Winter hardiness zones: 3-8.

Over the many millions of years of its existence, ginkgo has developed protective mechanisms against diseases and pests. Resistant to air pollution ^[17] .

Currently cultivated in most botanical gardens ^[8] . Often universally distributed in plantings as an ornamental plant .

Ginkgo bilobate - a tree up to 40 m high and a trunk diameter of up to 4.5 m ^[6] . The crown is initially pyramidal, grows with age.

This is a deciduous plant with a unique leaf form for modern gymnosperms - a fan-shaped bilobate plate 5–8 cm wide ^[18] , on a thin petiole up to 10 cm long. Veins with dichotomous branching. Leaves develop on long shoots individually and quickly, or on shortened groups of two to four slowly ^[8] .

The plant is dioecious ; pollen develops on male plants in the sergeiform collections of sporangia (spikelets). On female plants, two ovules develop on long legs. Both processes first occur in the 25-30 year of a tree’s life, only then it becomes possible to say whether it is female or male. Plants are pollinated by the wind in late spring. A few months after this, in the fall, fertilization occurs in pollinated ovules, yellowish seeds ripen from them and fall off, the embryo develops in them after decay. Seeds are somewhat reminiscent of apricot seeds, however, they have an unpleasant odor of rancid oil ( butyric acid gives it), they are round ^[8] . Seed peel consists of three layers: the outer one is fleshy, yellowish-amber, the middle one is hard, with longitudinal ribs and the inner one is thin paper-like ^[19] .

Usually they have a well-developed root system , are well resistant to strong winds and snow drifts. Some trees reach the age of 2500 years. In autumn, the leaves turn yellow and quickly fall off.

According to various sources, the ginkgo karyotype corresponds to the di-, tri- and tetraploid state, tetraploid plants predominate. n = 8, 4n = 32 ^[20] .

Boiled or fried ginkgo seeds have long been eaten in the areas of its growth and are used in Chinese medicine ^[8] .

Appreciated in decorative gardening for the beauty of the crown and openwork foliage. Often used as a tapeworm in landscaping.

In medicine

Recently, Ginkgo has become a "fashionable" drug, increasingly used as part of biologically active additives (BAA). Due to lower licensing requirements and control of the production of dietary supplements, as well as the absence of any control over the use of such additives, the number of registered unwanted side effects ( allergies , etc.) has gradually increased.

There are many opinions on the effectiveness of drugs containing ginkgo leaf compounds, from positive to critical articles in medical journals. A number of researchers believe that these drugs do not bring a noticeable improvement in memory ^[21] , although they increase the microcirculation of blood in tissues and organs. There are data from clinical studies indicating that prolonged use of the drug increases the risk of stroke ^{[22] [23]} . When used simultaneously with indirect anticoagulants and antiplatelet agents (including acetylsalicylic acid, aspirin , warfarin ), the risk of hemorrhagic strokes increases ^[24] , therefore, the appointment of ginkgo preparations without consulting a doctor is undesirable.

There are studies showing the absence of a noticeable effect of improving cognitive abilities in healthy people ^[25] ; also, in the course of a very extensive study carried out in collaboration with several American medical institutes, no positive effect was found on the likelihood of dementia in old age ^[26] .

The use of any ginkgo preparations (including dietary supplements) during pregnancy and breastfeeding is contraindicated.

FDA Position

The Ginkgo biloba product, extracted from the green leaves of Ginkgo, has not been approved by the American Food and Drug Administration (FDA) as safe and effective against any disease ^[27] .

In culture, several dozen forms differ in the shape of the crown, leaves and branching features ^[28] .

• ' Chris' Dwarf' (syn .: ' Chris s Dwarf' , ' Munchkin' ). Dwarf small-leaved form.
• ' Fastigiata Blagon' . French variety with conical crown. The leaves are green, yellow in the fall. It grows relatively slowly, an increase of 30-40 cm per year. Adult specimens can exceed 10 m, with a width of 2-3 m. Zones of frost resistance : from 3 ^[29] .

A tree grows in the Tokyo Botanical Garden, from which he took samples of Sakugoro Hirase , a Japanese scientist who discovered motile sperm in ginkgo. A memorial plate ^{[30] is} installed near the tree.

According to the results of the campaign "Alley of Russia" ^{[31], the} two-bladed ginkgo ^[32] was chosen as a symbol of the Perm Territory ^[33] .

On an interactive map of New York street trees, accounts were created with panoramic images for each of the 21,480 ginkgo specimens. It is estimated that ginkga plantations bring ecological benefits to the city of approximately $ 2 million per year ^[34] .

• Ginkgo // Great Soviet Encyclopedia : [in 30 vol.] / Ch. ed. A.M. Prokhorov . - 3rd ed. - M .: Soviet Encyclopedia, 1969-1978.
• Meyen S.V. Ginkgo - modern pteridosperm: (position of the ginkgoids in the gymnosperms) // Phylogeny of higher plants. M .: Nauka, 1982. S. 93-96.

• Ginkgo biloba (English) : information on the GRIN website.
• Ginkgo biloba (English) : information on the IPNI website.