Today’s Pu’er teas are almost all big-leaf teas, and the biggest difference in appearance from small-leaf teas is the leaves. Generally speaking, large, medium and small-leaf tea trees are distinguished according to the size of the mature leaves of the tea tree type.
Calculation formula: Leaf area = leaf length (excluding petiole and leaf tip) × leaf width (the middle part after the leaf base and leaf tip are folded in half) × 0.7 (Note: 0.7 is the leaf area coefficient), according to the calculation formula:
- If the leaf area is more than 60 square centimeters, it is called extra large leaf tea tree;
- The leaf area ≥ 40-60 square centimeters is called big-leaf tea tree;
- If the leaf area is more than 20-40 square centimeters, it is called middle-leaf tea tree;
- The leaf area ≥ 20 square centimeters is called small-leaf tea tree.
The leaves of small-leaved species are small, brittle and hard, and the leathery layer on the leaf surface is thicker. The thickness of the cuticle of the large-leaved species is 2-4 μm. The leaves are soft and the leathery layer on the leaf surface is also relatively thin; . The palisade tissue of large-leaf species usually has only one layer, which will increase under shade; there are more chloroplasts in the cells of large-leaf species, with 60-100 sheets, the photosynthetic rate is higher, the cell tissue is more loose, and the stomata on the back of the leaves are large and thick. Thin, yellow-green leaves, sharp and long leaf tips, long stems and internodes, fewer stomata per unit leaf area, larger guard cells in the stomata, and faster transpiration.
Small-leaved species have fewer chloroplasts in the cells, with 20-40 layers, lower photosynthetic rate, more and dense stomata on the back of the leaves, dark green leaves: blunter leaf tips. According to Yan Xuecheng’s research, the stomatal density of large-leaf tea trees is about 100/m², and the maximum is 150-180/m㎡; the medium- and small-leaf tea trees are about 200-260/m㎡.
Judging from the high-yield examples in the national red and green tea production areas, the weight of buds and leaves of large-leaf species is 0.4-0.5g, and the number of buds and leaves per 0.11㎡ of mining surface should be 200-250; . There must be 400 to 500 buds and leaves per 0.11 square meters of mining surface. The average weight of buds and leaves depends on the species of the tea tree. For example, under normal cultivation of Yunnan big-leaf species, there are generally 400-500 mixed buds with 1 bud and 2-3 leaves, and 500g; while the middle-leaf moss tea variety requires 2000. It only reaches 500g, and the leaflet type needs more than 3000 pieces to reach 500g.
Big-leaf tea is more durable than small-leaf tea, and more fragrant than small-leaf tea. In contrast, the sponge tissue cells of large-leaf tea are smaller, and the chemical composition of large-leaf tea and small-leaf tea are different. High-quality leaf tea contains more effective substances such as tea polyphenols and caffeine, and the tea made has a strong taste.
