Yunnan has the natural conditions to develop tea tree system. Tea trees like warm and humid climate, semi-hidden ecological environment and slightly acidic soil. Yunnan is located at high altitude and low latitude, and the Tropic of Cancer runs through the east and west, with mountains and rivers in the north and south. It has a tropical and subtropical climate, with no severe cold and heat, and abundant rainfall. Under the towering broad-leaved forest, a natural and hidden ecological environment has been formed. According to the law of phase distribution and the correlation with ocean distance, Yunnan soil is located between 97 39'-65 438+006 65 438+02' east longitude, close to the South China Sea. Therefore, this soil belongs to the fourth kind of forest soil-red soil. But most of them are latosol and latosol distributed in the south and southwest of Yunnan, with PH value of 4-5. These are all suitable conditions for the development of tea tree system. But this only shows the modern physical geography and climate, as for the ancient times.
From the perspective of paleogeography, paleoclimate and paleontology, Yunnan was located on the southern edge of the Laoya ancient land about 250 million years ago, facing the Tethys Sea. It has a flat terrain, mild climate and abundant rainfall. After a long geological period of Permian, Triassic, Cretaceous and Tertiary. Many angiosperms occur, grow and evolve here. Tropical and subtropical angiosperms such as tea trees are more suitable for their reproduction. Later, in several ice ages since the Quaternary, many plants on the earth were severely damaged. Only the southwest of China is less affected. Especially in the south and southwest of Yunnan, it has not been attacked by glaciers. The original species of many plants, such as Manglietia, Tilia amurensis, Pinion, Cycas, Bitter Lotus, have been preserved and are known as "living fossils". There are more than 15000 kinds of higher plants in Yunnan, accounting for more than half of the country, so Yunnan is called the "plant kingdom". Whether tea tree is one of the preserved plants. Can be investigated from related plants.
The distribution of related plants of tea tree is an important symbol to investigate the origin of tea tree. Yunnan is a place where related plants of tea tree are widely distributed and rich. There is a saying that "Yunshan tea is the best in the world". There are more than 380 species belonging to 23 genera in the world, and there are more than 260 species distributed in southwest China, of which Yunnan is the largest. According to the survey of "780" project of China Academy of Sciences, there are more than 70 species belonging to 8 genera in Tengchong County. According to the research of Professor Zhang Hongda, a plant taxonomist in China, tea plants are divided into Camelliaceae, Camellia, Camellia Subgenus and Camellia Group. There are 40 species of camellia in the world, 39 species in China and 33 species in Yunnan. It shows that Yunnan tea variety resources are very rich. At the same time, it can also be confirmed by the distribution of existing wild tea trees.
Wild tea trees in Yunnan are widely distributed. There are wild and cultivated tea trees in the deep forests of more than 40 counties in Yunnan. There is a wild tea tree in Mouding County, central Yunnan, with a height of 10.3m and a trunk circumference of 245cm. Hundreds of big tea trees have been found in Xinping County, one of which is 7.2m high, with a trunk diameter of114cm and a tree age of hundreds of years. The wild tea tree in Qianjiazhai, zhenyuan county is18.5m high,143.5cm in diameter at the base and 1000 years old. There are tea trees with a diameter of 1.2 1 m and a height of 34 m in Bada District, Menghai County, southern Yunnan Province, with a history of 1700 years. Nannuoshan tea tree is known as the king of tea trees. There are more than 200 tea trees in Xinyuan Township, Yaojie District, Fengqing County, southwest Yunnan, all of which are 50-70 cm in diameter. The trees are tall and widely distributed, which is amazing. Whether these big tea trees have the biological characteristics of ancient tea trees needs biochemical analysis.
Yunnan tea tree has the biological characteristics of ancient tea tree, and the biological evolution has gone through the evolution process from simple to complex and from low to high from occurrence, development to reproduction. The metabolism of tea tree is mainly the change of catechol quality and quantity. Through biochemical analysis, Yunnan Daye tea, whether wild or cultivated, synthesized more L- epicatechin gallate than L- epicatechin gallate. This proves that Yunnan big-leaf tea tree belongs to simple low-level metabolism and has the biological characteristics of ancient tea trees.
Based on this, scientists have investigated and demonstrated that "Yunnan is the origin of tea trees", which is an indisputable fact.