The origin of the tea tree is about the Oligocene. Due to the geological evolution from the third century, the ascending movement in the Himalayas and the rise of the Hengduan Mountains in the southwestern terraces have emerged, so that the origin of the tea tree in the fourth century is in the main part of the Yunnan-Guizhou Plateau. Due to the rise of the terrain and the emergence of glaciers and floods, the fractured mountain valleys have formed a vertical climatic zone in the same climate zone, namely tropical, subtropical and temperate zones. Tea trees are also forced to have homologous branches. Because of their long history in different geographical conditions and climatic conditions, the morphological structure, physiological characteristics and material metabolism of tea trees have gradually changed to adapt to the new environment.
The evolution of tea trees is mainly manifested in the fact that the tree type changes from arbor to small arbor and shrub, the trunk and the central axis become the axis, the leaves from the large leaves to the small leaves, the crowns of tree from small to large, and the petals from the plexus to the single lobes, the shell is from thick to thin, and the seed coat is from rough to smooth mesophyll cells. This process includes three types: wild type, intermediate type and cultivated type, and produces a wide variety of genotypes; introduction, domestication and selection on cultivation also lead to the formation of numerous horticultural varieties. The evolution of tea traits is irreversible. For example, the small leaf tea trees in the shrubs do not have the characteristics of the large leaves tea trees even if they grow under tropical hot and humid conditions.
1 Wild type tea plant. Also known as the original tea tree. It has primitive characteristics during phylogeny: arbor and small tree. Overwinter bud scales 3-5. The leaves are large, 10-25 cm long, the stratum corneum is thick, the leaves are flat or slightly ridged, and the leaf margins are blunt teeth. The amino acids, tea polyphenols, catechins, and caffeine in the leaves are all available. The finished tea has a low aroma, a low taste and a lack of freshness. Long-term growth under specific relatively stable ecological conditions, due to strong conservation, artificial reproduction, migration success rate is low.
2 Cultivated tea plant (cultural type tea plant). Also known as evolutionary tea tree. The main characteristics are: shrubs, small tree trees, tree postures open or semi-open. Overwinter bud scales 2-3. The leaves are 6-15 cm long, the leaves are mostly green or dark green, and the leaves have fine sharp teeth. The amino acids, tea polyphenols, catechins, and caffeine in the leaves are all available. The quality of finished tea is mostly excellent. Cultivated tea trees are formed under long-term natural selection and artificial cultivation conditions.
