1.根原茎的性状与块根的形成:根是形成茎、叶和薯块的基础,栽插的苗,通常是从苗的切口或节的部位发根,成为块根的主要是后者.节内部根的起源,即形成根原基的位置在叶痕或枝痕的部位有靠近茎的维管束.根原基第一次形成在展开叶近上位节左右,从下位节依次增加根原基的数目,在展开叶下5～6节大致一定节的左右同时是4条左右.根原基首先增粗,随后增粗并增长,最后只增长,但和苗床的发根情况有区别,通常是有各种程度的 1. Roots stem traits and root formation: The root is the formation of stems, leaves and tubers, planted seedlings, usually from the seedlings cut or section of the root hair, the root is the root of the latter section. The root of the inner root, which forms the root primordium, has a vascular bundle close to the stem at the location of the leaf scar or branch scar. The root primordium is formed for the first time around the upper epidermis of the expanded leaf and in turn increases the number of root primordium from the lower stalk, In the development of leaf about 5 to 6 about a certain section of the left and right at the same time is about 4. Root primordia first thickening, then thickening and growth, and finally only growth, but the seedling bed and hair root conditions are different, usually there are various Degree