(2) Tea trees need to absorb water and inorganic salts from the soil during the growth process, and the main part of root tip absorbing water and inorganic salts is the mature area, and some epidermal cells in the mature area protrude outward to form root hairs.
(3)① Cutting belongs to asexual propagation. ② Experimental name: The relationship between the rooting number of cutting branches and the direction of incision under branches. ③ Unreasonable point: the number of selected materials is too small, and both groups should keep the same number of blades.
So the answer is: (1) organ; Quilt;
(2) moisture and inorganic salts; There are a lot of root hairs in the mature area of root tip;
(3) The first answer: ① asexual love; (2) The relationship between the rooting number of cutting branches and the direction of incision under branches; ③ The number of selected materials is too small, and both groups should keep the same number of blades.